力扣多线程练习----交替打印FooBar
作者:互联网
交替打印FooBar
题目
两个不同的线程将会共用一个 FooBar 实例。其中一个线程将会调用 foo() 方法,另一个线程将会调用 bar() 方法。
请设计修改程序,以确保 “foobar” 被输出 n 次。
Semaphore
代码
import java.util.concurrent.Semaphore;
public class FooBar {
private int n;
public FooBar(int n) {
this.n = n;
}
Semaphore semaphoreFoo=new Semaphore(1);
Semaphore semaphoreBar=new Semaphore(0);
public void foo(Runnable printFoo) throws InterruptedException {
for (int i = 0; i < n; i++) {
semaphoreFoo.acquire();
printFoo.run();
semaphoreBar.release();
}
}
public void bar(Runnable printBar) throws InterruptedException {
for (int i = 0; i < n; i++) {
semaphoreBar.acquire();
printBar.run();
semaphoreFoo.release();
}
}
public static void main(String[] args) throws InterruptedException {
FooBar fooBar=new FooBar(10);
new Thread(()->{
try {
fooBar.foo(new PrintFoo());
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
new Thread(()->{
try {
fooBar.bar(new PrintFar());
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
}
class PrintFoo implements Runnable{
@Override
public void run() {
System.out.print("foo");
}
}
class PrintFar implements Runnable{
@Override
public void run() {
System.out.print("bar");
}
}
Lock公平锁
public class FooBar {
private int n;
public FooBar(int n) {
this.n = n;
}
Lock lock=new ReentrantLock(true);
static volatile boolean flag=true;
public void foo(Runnable printFoo) throws InterruptedException {
for (int i = 0; i < n; ) {
lock.lock();
try {
if(flag){
printFoo.run();
i++;
flag=false;
}
}finally {
lock.unlock();
}
}
}
public void bar(Runnable printBar) throws InterruptedException {
for (int i = 0; i < n; ) {
lock.lock();
try {
if(!flag){
printBar.run();
i++;
flag=true;
}
}finally {
lock.unlock();
}
}
}
public static void main(String[] args) throws InterruptedException {
FooBar fooBar=new FooBar(10);
new Thread(()->{
try {
fooBar.foo(new PrintFoo());
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
new Thread(()->{
try {
fooBar.bar(new PrintFar());
} catch (InterruptedException e) {
e.printStackTrace();
}
}).start();
}
}
class PrintFoo implements Runnable{
@Override
public void run() {
System.out.print("foo");
}
}
class PrintFar implements Runnable{
@Override
public void run() {
System.out.print("bar");
}
}
标签:int,FooBar,void,InterruptedException,----,new,多线程,public 来源: https://blog.csdn.net/qq_22130209/article/details/115041803