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arthas简单使用

作者:互联网

arthas 解决了哪些问题?看看官方的回答

这个类从哪个 jar 包加载的?为什么会报各种类相关的 Exception?

我改的代码为什么没有执行到?难道是我没 commit?分支搞错了?

遇到问题无法在线上 debug,难道只能通过加日志再重新发布吗?

线上遇到某个用户的数据处理有问题,但线上同样无法 debug,线下无法重现!

是否有一个全局视角来查看系统的运行状况?

有什么办法可以监控到JVM的实时运行状态?

怎么快速定位应用的热点,生成火焰图?

怎样直接从JVM内查找某个类的实例

案例

线程相关

//启动方式
//java -Xms27M -Xmx27M -XX:+UseParallelGC -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGC -XX:+PrintGCDetails BlockTest
//参数不怎么了解的可以看下jvm篇
public class BlockTest {
    public static void main(String[] args) throws Exception {
        CountDownLatch latch = new CountDownLatch(2);
        Object o1 = new Object();
        Object o2 = new Object();
        Thread t1 = new Thread(() -> {
            synchronized (o1) {
                System.out.println("t1 o1");
                 synchronized (o2){
                      System.out.println("t1 o2");
                 }
            }
            latch.countDown();
        });
        Thread t2 = new Thread(()->{
             synchronized (o2){
                  System.out.println("t2 o2");
                  synchronized (o1){
                       System.out.println("t2 o1");
                  }
             }
             latch.countDown();
        });
        t1.start();
        t2.start();
        latch.await();
    }
}

内存相关

// 启动命令 nohup java -Xms27M -Xmx27M -XX:+UseParallelGC -XX:+HeapDumpOnOutOfMemoryError -XX:+PrintGC -XX:+PrintGCDetails MemoryTest 2>&1 &
public class MemoryTest {
    public static List list = new LinkedList();
    public static void main(String[] args) throws InterruptedException {
        while(true){
                list.add(new MemoryObj("1",1, new int[]{1}));
                Thread.sleep(10);
        }

    }
    static class MemoryObj{
        private String str;
        private Integer integer;
        private int[] arr;
        public MemoryObj(String str, Integer integer, int[] arr) {
            this.str = str;
            this.integer = integer;
            this.arr = arr;
        }
    }
}

官方提供的SpringBoot

# 访问的时候比较慢
# 也可以直接在官方提供的虚拟机上操作
# https://arthas.aliyun.com/doc/arthas-tutorials.html?language=cn&id=arthas-advanced
wget https://github.com/hengyunabc/spring-boot-inside/raw/master/demo-arthas-spring-boot/demo-arthas-spring-boot.jar
java -jar demo-arthas-spring-boot.jar

操作

下载arthas-boot.jar

https://github.com/alibaba/arthas/releases

启动

java -jar arthas-boot.jar --target-ip 0.0.0.0 --telnet-port 9998 --http-port 9999
# 自动获取java程序(类似jps命令),然后排号,使用者输入对应的需要可进行监控
--target-ip 指定外部访问ip,默认未127.0.0.1
--use-version 3.1.0 指定使用版本
--telnet-port 9999 监听telnet端口
--http-port 监听http端口
-v 打印运行时详情

命令

dashboard 列出系统中线程、内存、os等线管信息在这里插入图片描述

列说明
ID: Java级别的线程ID,注意这个ID不能跟jstack中的nativeID一一对应。
NAME: 线程名
GROUP: 线程组名
PRIORITY: 线程优先级, 1~10之间的数字,越大表示优先级越高
STATE: 线程的状态
CPU%: 线程的cpu使用率。比如采样间隔1000ms,某个线程的增量cpu时间为100ms,则cpu使用率=100/1000=10%
DELTA_TIME: 上次采样之后线程运行增量CPU时间,数据格式为秒
TIME: 线程运行总CPU时间,数据格式为分:秒
INTERRUPTED: 线程当前的中断位状态
DAEMON: 是否是daemon线程

thread 查看当前线程信息,查看线程的堆栈

thread -n 3 : 打印出前几个最忙的线程
thread -b : 查看程序中被阻塞的线程(线程状态为Blocked状态)
thread all :查看进程中所有的线程
thread tid :查看具体线程堆栈信息
thread -i ms : 指定特定时间采样,毫秒 
thread --state threadstate : 指定线程状态查找列表
thread -n 3 -i 5000 :查看5秒内的CPU使用率top n线程栈
id为-1的线程为JVM内部线程
JIT编译线程: 如 C1 CompilerThread0, C2 CompilerThread0
GC线程: 如GC Thread0, G1 Young RemSet Sampling
其它内部线程: 如VM Periodic Task Thread, VM Thread, Service Thread

JVM 查看当前JVM信息

RUNTIME  运行信息                                                                                                                                                                                   
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MACHINE-NAME                                          21058@worker2                                                                                                                        
 JVM-START-TIME                                        2022-01-04 14:34:22                                                                                                                  
 MANAGEMENT-SPEC-VERSION                               1.2                                                                                                                                  
 SPEC-NAME                                             Java Virtual Machine Specification                                                                                                   
 SPEC-VENDOR                                           Oracle Corporation                                                                                                                   
 SPEC-VERSION                                          1.8                                                                                                                                  
 VM-NAME                                               Java HotSpot(TM) 64-Bit Server VM                                                                                                    
 VM-VENDOR                                             Oracle Corporation                                                                                                                   
 VM-VERSION                                            25.221-b11                                                                                                                           
 INPUT-ARGUMENTS                                       []                                                                                                                                   
 CLASS-PATH                                            .:/home/jdk1.8.0_221/lib/dt.jar:/home/jdk1.8.0_221/lib/tools.jar                                                                     
 BOOT-CLASS-PATH                                       /home/jdk1.8.0_221/jre/lib/resources.jar:/home/jdk1.8.0_221/jre/lib/rt.jar:/home/jdk1.8.0_221/jre/lib/sunrsasign.jar:/home/jdk1.8.0_ 
                                                       221/jre/lib/jsse.jar:/home/jdk1.8.0_221/jre/lib/jce.jar:/home/jdk1.8.0_221/jre/lib/charsets.jar:/home/jdk1.8.0_221/jre/lib/jfr.jar:/ 
                                                       home/jdk1.8.0_221/jre/classes                                                                                                        
 LIBRARY-PATH                                          /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib                                                                         
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 CLASS-LOADING    类加载                                                                                                                                                                          
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 LOADED-CLASS-COUNT                                    3500                                                                                                                                 
 TOTAL-LOADED-CLASS-COUNT                              3500                                                                                                                                 
 UNLOADED-CLASS-COUNT                                  0                                                                                                                                    
 IS-VERBOSE                                            false                                                                                                                                
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 COMPILATION    虚拟机                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 NAME                                                  HotSpot 64-Bit Tiered Compilers                                                                                                      
 TOTAL-COMPILE-TIME                                    2517                                                                                                                                 
 [time (ms)]                                                                                                                                                                                
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 GARBAGE-COLLECTORS   垃圾回收器                                                                                                                                                                      
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 PS Scavenge                                           name : PS Scavenge                                                                                                                   
 [count/time (ms)]                                     collectionCount : 1                                                                                                                  
                                                       collectionTime : 18                                                                                                                  
                                                                                                                                                                                            
 PS MarkSweep                                          name : PS MarkSweep                                                                                                                  
 [count/time (ms)]                                     collectionCount : 0                                                                                                                  
                                                       collectionTime : 0                                                                                                                   
                                                                                                                                                                                            
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MEMORY-MANAGERS   内存管理                                                                                                                                                                         
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 CodeCacheManager                                      Code Cache                                                                                                                           
                                                                                                                                                                                            
 Metaspace Manager                                     Metaspace                                                                                                                            
                                                       Compressed Class Space                                                                                                               
                                                                                                                                                                                            
 PS Scavenge                                           PS Eden Space                                                                                                                        
                                                       PS Survivor Space                                                                                                                    
                                                                                                                                                                                            
 PS MarkSweep                                          PS Eden Space                                                                                                                        
                                                       PS Survivor Space                                                                                                                    
                                                       PS Old Gen                                                                                                                           
                                                                                                                                                                                            
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MEMORY       内存                                                                                                                                                                              
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 HEAP-MEMORY-USAGE                                     init : 262144000(250.0 MiB)                                                                                                          
 [memory in bytes]                                     used : 53054408(50.6 MiB)                                                                                                            
                                                       committed : 251658240(240.0 MiB)                                                                                                     
                                                       max : 3702521856(3.4 GiB)                                                                                                            
                                                                                                                                                                                            
 NO-HEAP-MEMORY-USAGE                                  init : 2555904(2.4 MiB)                                                                                                              
 [memory in bytes]                                     used : 29251568(27.9 MiB)                                                                                                            
                                                       committed : 29949952(28.6 MiB)                                                                                                       
                                                       max : -1(-1 B)                                                                                                                       
                                                                                                                                                                                            
 PENDING-FINALIZE-COUNT                                0                                                                                                                                    
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 OPERATING-SYSTEM     操作系统                                                                                                                                                                      
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 OS                                                    Linux                                                                                                                                
 ARCH                                                  amd64                                                                                                                                
 PROCESSORS-COUNT                                      8                                                                                                                                    
 LOAD-AVERAGE                                          4.22                                                                                                                                 
 VERSION                                               3.10.0-1127.13.1.el7.x86_64                                                                                                          
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 THREAD     线程                                                                                                                                                                                
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 COUNT                                                 18                                                                                                                                   
 DAEMON-COUNT                                          13                                                                                                                                   
 PEAK-COUNT                                            19                                                                                                                                   
 STARTED-COUNT                                         22                                                                                                                                   
 DEADLOCK-COUNT                                        0                                                                                                                                    
                                                                                                                                                                                            
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 FILE-DESCRIPTOR     文件描述                                                                                                                                                                       
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 MAX-FILE-DESCRIPTOR-COUNT                             65535                                                                                                                                
 OPEN-FILE-DESCRIPTOR-COUNT                            174 

THREAD相关
COUNT: JVM当前活跃的线程数
DAEMON-COUNT: JVM当前活跃的守护线程数
PEAK-COUNT: 从JVM启动开始曾经活着的最大线程数
STARTED-COUNT: 从JVM启动开始总共启动过的线程次数
DEADLOCK-COUNT: JVM当前死锁的线程数
文件描述符相关
MAX-FILE-DESCRIPTOR-COUNT:JVM进程最大可以打开的文件描述符数
OPEN-FILE-DESCRIPTOR-COUNT:JVM当前打开的文件描述符数

sysprop 系统属性


 KEY                                   VALUE                                                                                                                                                
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 awt.toolkit                           sun.awt.X11.XToolkit                                                                                                                                 
 file.encoding.pkg                     sun.io                                                                                                                                               
 java.specification.version            1.8                                                                                                                                                  
 sun.cpu.isalist                                                                                                                                                                            
 sun.jnu.encoding                      UTF-8                                                                                                                                                
 java.class.path                       .:/home/jdk1.8.0_221/lib/dt.jar:/home/jdk1.8.0_221/lib/tools.jar                                                                                     
 java.vm.vendor                        Oracle Corporation                                                                                                                                   
 sun.arch.data.model                   64                                                                                                                                                   
 java.vendor.url                       http://java.oracle.com/                                                                                                                              
 user.timezone                         Asia/Shanghai                                                                                                                                        
 os.name                               Linux                                                                                                                                                
 java.vm.specification.version         1.8                                                                                                                                                  
 user.country                          CN                                                                                                                                                   
 sun.java.launcher                     SUN_STANDARD                                                                                                                                         
 sun.boot.library.path                 /home/jdk1.8.0_221/jre/lib/amd64                                                                                                                     
 sun.java.command                      CpuTest                                                                                                                                              
 sun.cpu.endian                        little                                                                                                                                               
 user.home                             /root                                                                                                                                                
 user.language                         zh                                                                                                                                                   
 java.specification.vendor             Oracle Corporation                                                                                                                                   
 java.home                             /home/jdk1.8.0_221/jre                                                                                                                               
 file.separator                        /                                                                                                                                                    
 line.separator                                                                                                                                                                             
                                                                                                                                                                                            
 java.vm.specification.vendor          Oracle Corporation                                                                                                                                   
 java.specification.name               Java Platform API Specification                                                                                                                      
 java.awt.graphicsenv                  sun.awt.X11GraphicsEnvironment                                                                                                                       
 sun.boot.class.path                   /home/jdk1.8.0_221/jre/lib/resources.jar:/home/jdk1.8.0_221/jre/lib/rt.jar:/home/jdk1.8.0_221/jre/lib/sunrsasign.jar:/home/jdk1.8.0_221/jre/lib/jsse 
                                       .jar:/home/jdk1.8.0_221/jre/lib/jce.jar:/home/jdk1.8.0_221/jre/lib/charsets.jar:/home/jdk1.8.0_221/jre/lib/jfr.jar:/home/jdk1.8.0_221/jre/classes    
 sun.management.compiler               HotSpot 64-Bit Tiered Compilers                                                                                                                      
 java.runtime.version                  1.8.0_221-b11                                                                                                                                        
 user.name                             root                                                                                                                                                 
 path.separator                        :                                                                                                                                                    
 os.version                            3.10.0-1127.13.1.el7.x86_64                                                                                                                          
 java.endorsed.dirs                    /home/jdk1.8.0_221/jre/lib/endorsed                                                                                                                  
 java.runtime.name                     Java(TM) SE Runtime Environment                                                                                                                      
 file.encoding                         UTF-8                                                                                                                                                
 sun.nio.ch.bugLevel                                                                                                                                                                        
 java.vm.name                          Java HotSpot(TM) 64-Bit Server VM                                                                                                                    
 java.vendor.url.bug                   http://bugreport.sun.com/bugreport/                                                                                                                  
 java.io.tmpdir                        /tmp                                                                                                                                                 
 java.version                          1.8.0_221                                                                                                                                            
 user.dir                              /opt/arthas                                                                                                                                          
 os.arch                               amd64                                                                                                                                                
 java.vm.specification.name            Java Virtual Machine Specification                                                                                                                   
 java.awt.printerjob                   sun.print.PSPrinterJob                                                                                                                               
 sun.os.patch.level                    unknown                                                                                                                                              
 java.library.path                     /usr/java/packages/lib/amd64:/usr/lib64:/lib64:/lib:/usr/lib                                                                                         
 java.vm.info                          mixed mode                                                                                                                                           
 java.vendor                           Oracle Corporation                                                                                                                                   
 java.vm.version                       25.221-b11                                                                                                                                           
 java.ext.dirs                         /home/jdk1.8.0_221/jre/lib/ext:/usr/java/packages/lib/ext                                                                                            
 sun.io.unicode.encoding               UnicodeLittle                                                                                                                                        
 java.class.version                    52.0        

sysenv
环境属性
 KEY                                   VALUE                                                                                                                                                
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 PATH                                  /home/jdk1.8.0_221/bin:/usr/local/sbin:/usr/local/bin:/usr/sbin:/usr/bin:/opt/rocketmq4.7/bin:/opt/mysql5.7/bin:/root/bin                            
 HISTCONTROL                           ignoredups                                                                                                                                           
 HISTSIZE                              1000                                                                                                                                                 
 JAVA_HOME                             /home/jdk1.8.0_221                                                                                                                                   
 TERM                                  xterm                                                                                                                                                
 LANG                                  zh_CN.UTF-8                                                                                                                                          
 XDG_SESSION_ID                        761                                                                                                                                                  
 SELINUX_LEVEL_REQUESTED                                                                                                                                                                    
 SELINUX_ROLE_REQUESTED                                                                                                                                                                     
 ROCKETMQ_HOME                         /opt/rocketmq4.7                                                                                                                                     
 MAIL                                  /var/spool/mail/root                                                                                                                                 
 LOGNAME                               root                                                                                                                                                 
 PWD                                   /opt/arthas                                                                                                                                          
 _                                     /usr/bin/nohup                                                                                                                                       
 LESSOPEN                              ||/usr/bin/lesspipe.sh %s                                                                                                                            
 SHELL                                 /bin/bash                                                                                                                                            
 SELINUX_USE_CURRENT_RANGE                                                                                                                                                                  
 SSH_TTY                               /dev/pts/3                                                                                                                                           
 SSH_CLIENT                            172.16.193.6 12543 22                                                                                                                                
 OLDPWD                                /root                                                                                                                                                
 USER                                  root                                                                                                                                                 
 CLASSPATH                             .:/home/jdk1.8.0_221/lib/dt.jar:/home/jdk1.8.0_221/lib/tools.jar                                                                                     
 SSH_CONNECTION                        172.16.193.6 12543 172.16.14.108 22                                                                                                                  
 HOSTNAME                              worker2                                                                                                                                              
 XDG_RUNTIME_DIR                       /run/user/0                                                                                                                                          
 LS_COLORS                             rs=0:di=01;34:ln=01;36:mh=00:pi=40;33:so=01;35:do=01;35:bd=40;33;01:cd=40;33;01:or=40;31;01:mi=01;05;37;41:su=37;41:sg=30;43:ca=30;41:tw=30;42:ow=34 
                                       ;42:st=37;44:ex=01;32:*.tar=01;31:*.tgz=01;31:*.arc=01;31:*.arj=01;31:*.taz=01;31:*.lha=01;31:*.lz4=01;31:*.lzh=01;31:*.lzma=01;31:*.tlz=01;31:*.txz 
                                       =01;31:*.tzo=01;31:*.t7z=01;31:*.zip=01;31:*.z=01;31:*.Z=01;31:*.dz=01;31:*.gz=01;31:*.lrz=01;31:*.lz=01;31:*.lzo=01;31:*.xz=01;31:*.bz2=01;31:*.bz= 
                                       01;31:*.tbz=01;31:*.tbz2=01;31:*.tz=01;31:*.deb=01;31:*.rpm=01;31:*.jar=01;31:*.war=01;31:*.ear=01;31:*.sar=01;31:*.rar=01;31:*.alz=01;31:*.ace=01;3 
                                       1:*.zoo=01;31:*.cpio=01;31:*.7z=01;31:*.rz=01;31:*.cab=01;31:*.jpg=01;35:*.jpeg=01;35:*.gif=01;35:*.bmp=01;35:*.pbm=01;35:*.pgm=01;35:*.ppm=01;35:*. 
                                       tga=01;35:*.xbm=01;35:*.xpm=01;35:*.tif=01;35:*.tiff=01;35:*.png=01;35:*.svg=01;35:*.svgz=01;35:*.mng=01;35:*.pcx=01;35:*.mov=01;35:*.mpg=01;35:*.mp 
                                       eg=01;35:*.m2v=01;35:*.mkv=01;35:*.webm=01;35:*.ogm=01;35:*.mp4=01;35:*.m4v=01;35:*.mp4v=01;35:*.vob=01;35:*.qt=01;35:*.nuv=01;35:*.wmv=01;35:*.asf= 
                                       01;35:*.rm=01;35:*.rmvb=01;35:*.flc=01;35:*.avi=01;35:*.fli=01;35:*.flv=01;35:*.gl=01;35:*.dl=01;35:*.xcf=01;35:*.xwd=01;35:*.yuv=01;35:*.cgm=01;35: 
                                       *.emf=01;35:*.axv=01;35:*.anx=01;35:*.ogv=01;35:*.ogx=01;35:*.aac=01;36:*.au=01;36:*.flac=01;36:*.mid=01;36:*.midi=01;36:*.mka=01;36:*.mp3=01;36:*.m 
                                       pc=01;36:*.ogg=01;36:*.ra=01;36:*.wav=01;36:*.axa=01;36:*.oga=01;36:*.spx=01;36:*.xspf=01;36:                                                        
 HOME                                  /root                                                                                                                                                
 SHLVL                                 1 

vmoption 参数
 KEY                                            VALUE                                          ORIGIN                                         WRITEABLE                                     
--------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------------
 HeapDumpBeforeFullGC                           false                                          DEFAULT                                        true                                          
 HeapDumpAfterFullGC                            false                                          DEFAULT                                        true                                          
 HeapDumpOnOutOfMemoryError                     false                                          DEFAULT                                        true                                          
 HeapDumpPath                                                                                  DEFAULT                                        true                                          
 CMSAbortablePrecleanWaitMillis                 100                                            DEFAULT                                        true                                          
 CMSWaitDuration                                2000                                           DEFAULT                                        true                                          
 CMSTriggerInterval                             -1                                             DEFAULT                                        true                                          
 PrintGC                                        false                                          DEFAULT                                        true                                          
 PrintGCDetails                                 false                                          DEFAULT                                        true                                          
 PrintGCDateStamps                              false                                          DEFAULT                                        true                                          
 PrintGCTimeStamps                              false                                          DEFAULT                                        true                                          
 PrintGCID                                      false                                          DEFAULT                                        true                                          
 PrintClassHistogramBeforeFullGC                false                                          DEFAULT                                        true                                          
 PrintClassHistogramAfterFullGC                 false                                          DEFAULT                                        true                                          
 PrintClassHistogram                            false                                          DEFAULT                                        true                                          
 MinHeapFreeRatio                               0                                              DEFAULT                                        true                                          
 MaxHeapFreeRatio                               100                                            DEFAULT                                        true                                          
 PrintConcurrentLocks                           false                                          DEFAULT                                        true                                          
 UnlockCommercialFeatures                       false                                          DEFAULT                                        true                                          

perfcounter 性能监控

perfcounter -d 打印更详细信息

mbean 查看或监控 Mbean 的属性信息

每隔一秒打印一次Threading信息
mbean -i 1000 java.lang:type=Threading *Count
打印出Runtime信息(运行时信息,如运行时参数)
mbean java.lang:type=Runtime

java.lang:type=MemoryPool,name=Metaspace
java.lang:type=MemoryPool,name=PS Old Gen
java.lang:type=GarbageCollector,name=PS Scavenge
java.lang:type=MemoryPool,name=PS Eden Space
JMImplementation:type=MBeanServerDelegate
java.lang:type=Runtime
java.lang:type=Threading
java.lang:type=OperatingSystem
java.lang:type=MemoryPool,name=Code Cache
java.nio:type=BufferPool,name=direct
java.lang:type=Compilation
java.lang:type=MemoryManager,name=CodeCacheManager
java.lang:type=MemoryPool,name=Compressed Class Space
java.lang:type=Memory
java.nio:type=BufferPool,name=mapped
java.util.logging:type=Logging
java.lang:type=MemoryPool,name=PS Survivor Space
java.lang:type=ClassLoading
java.lang:type=MemoryManager,name=Metaspace Manager
com.sun.management:type=DiagnosticCommand
java.lang:type=GarbageCollector,name=PS MarkSweep
com.sun.management:type=HotSpotDiagnostic

getstatic 查看类的静态属性

sc 查看JVM已加载的类信息

sc -d -f BlockTest
-d 打印详细信息
-f 打印类得Field

sm 查看已加载类的方法信息

和sc使用方法一致

dump 已加载类的 bytecode

dump -d ./temp BlockTest
-d 指定导出的路径

heapdump 导出堆

heapdump ./temp/block.hprof

vmtool 查询内存对象,强制GC

vmtool --action getInstances --classLoaderClass sun.misc.Launcher$ExtClassLoader --className java.util.concurrent.CountDownLatch --limit 100
--limit 100 指定返回条数
vmtool --action getInstances --classLoaderClass sun.misc.Launcher$AppClassLoader --className BlockTest
--classLoaderClass 指定类加载器

vmtool --action forceGc 强制GC

jad 反编译

jad --source-only BlockTest main
--source-only 只展示自己的代码
--lineNumber false 隐藏行号
--main 指定类的方法

classloader 查看类加载器

classloader 
-t 列出继承树
-l 详情

mc 内存编译器,编译.java文件生成.class

mc --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader /tmp/UserController.java -d /tmp

redefine 热替换

redefine /tmp/com/example/demo/arthas/user/UserController.class

热替换流程
1、找到对应的类进行反编译
    jad --source-only com.example.demo.arthas.user.UserController > /tmp/UserController.java
2、修改class文件
3、找到对应class文件类加载器哈希code
    sc -d *UserController | grep classLoaderHash
    classLoaderHash   728938a9
4、重新编译目标类
    mc --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader /tmp/UserController.java -d /tmp
    /tmp/com/example/demo/arthas/user/UserController.class
5、使用redefine命令重新加载新编译好的UserController.class
    redefine /tmp/com/example/demo/arthas/user/UserController.class
6、再次验证对应的代码是否已经更改

watch 函数执行数据观测(捕获异常)

watch com.example.demo.arthas.user.UserController * '{params, throwExp}' -x 2
-x 2 展开

watch com.example.demo.arthas.user.UserController * "{params[0],throwExp}" -e
-e 只捕获抛出异常的请求

动态更改应用日志级别
1、查询类加载器哈希code
    sc -d com.example.demo.arthas.user.UserController | grep classLoaderHash
    classLoaderHash   728938a9
2、用ognl获取logger
    ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger'
3、单独设置UserController的日志级别
    ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger.setLevel(@ch.qos.logback.classic.Level@DEBUG)'
4、再次获取
    ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@com.example.demo.arthas.user.UserController@logger' 
5、设置全局level等级
    ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '@org.slf4j.LoggerFactory@getLogger("root").setLevel(@ch.qos.logback.classic.Level@DEBUG)'
-----------logger冲突排查-------------------
6、获取实际的logger配置文件
    ognl --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader '#map1=@org.slf4j.LoggerFactory@getLogger("root").loggerContext.objectMap, #map1.get("CONFIGURATION_WATCH_LIST")'
7、查找可能存在的logger配置文件
    classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback-spring.xml
8、可以尝试加载容易冲突的文件
    classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r logback.xml
    classloader --classLoaderClass org.springframework.boot.loader.LaunchedURLClassLoader -r log4j.properties

tt 记录下指定方法每次调用的入参和返回信息,并能对这些不同的时间下调用进行观测

获取请求
  tt -t org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter invokeHandlerMethod
获取spring应用上下文
  tt -i 1000 -w 'target.getApplicationContext()'
获取spring中bean并调用方法
  tt -i 1000 -w 'target.getApplicationContext().getBean("helloWorldService").getHelloMessage()'

trace方法内部调用路径,并输出方法路径上的每个节点上耗时

如访问接口401时
  trace javax.servlet.Filter *
    +---[0.162227ms] javax.servlet.FilterChain:doFilter() #99
        |               |               |               |       |   `---[0.093406ms] com.example.demo.arthas.AdminFilterConfig$AdminFilter:doFilter()
        |               |               |               |       |       `---[0.049584ms] javax.servlet.http.HttpServletResponse:sendError() #38

通过stack获取调用栈
	stack javax.servlet.http.HttpServletResponse sendError 'params[0]==401'
和打印异常调用栈一样的清晰

profiler 应用热点火焰图

开启
    profiler start
查看统计数量
    profiler getSamples
查看状态及统计的时间
    profiler status
结束并生成html页面
    profiler stop --format html
    生成文件位置
      profiler output file: /opt/arthas/app/arthas-output/20220224-175834.html
访问
    http://localhost:${http-port}/arthas-output

在这里插入图片描述

标签:01,java,--,31,使用,35,arthas,线程,简单
来源: https://blog.csdn.net/xiaomengxin521/article/details/123197229