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六十三、Spark-读取数据并写入数据库

2022-01-26 11:59:48 作者：互联网

支持的数据源-JDBC

需求说明：使用Spark流式计算将数据写入MySQL，并读取数据库信息进行打印

文章目录

项目主体架构

pom.xml依赖

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>cn.itcast</groupId>
    <artifactId>SparkDemo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <repositories>
        <repository>
            <id>aliyun</id>
            <url>http://maven.aliyun.com/nexus/content/groups/public/</url>
        </repository>
        <repository>
            <id>apache</id>
            <url>https://repository.apache.org/content/repositories/snapshots/</url>
        </repository>
        <repository>
            <id>cloudera</id>
            <url>https://repository.cloudera.com/artifactory/cloudera-repos/</url>
        </repository>
    </repositories>
    <properties>
        <encoding>UTF-8</encoding>
        <maven.compiler.source>1.8</maven.compiler.source>
        <maven.compiler.target>1.8</maven.compiler.target>
        <scala.version>2.12.11</scala.version>
        <spark.version>3.0.1</spark.version>
        <hadoop.version>2.7.5</hadoop.version>
    </properties>
    <dependencies>
        <!--依赖Scala语言-->
        <dependency>
            <groupId>org.scala-lang</groupId>
            <artifactId>scala-library</artifactId>
            <version>${scala.version}</version>
        </dependency>

        <!--SparkCore依赖-->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <!-- spark-streaming-->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-streaming_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <!--spark-streaming+Kafka依赖-->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-streaming-kafka-0-10_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <!--SparkSQL依赖-->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <!--SparkSQL+ Hive依赖-->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-hive_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-hive-thriftserver_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <!--StructuredStreaming+Kafka依赖-->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-sql-kafka-0-10_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <!-- SparkMlLib机器学习模块,里面有ALS推荐算法-->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-mllib_2.12</artifactId>
            <version>${spark.version}</version>
        </dependency>

        <dependency>
            <groupId>org.apache.hadoop</groupId>
            <artifactId>hadoop-client</artifactId>
            <version>2.7.5</version>
        </dependency>

        <dependency>
            <groupId>com.hankcs</groupId>
            <artifactId>hanlp</artifactId>
            <version>portable-1.7.7</version>
        </dependency>

        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <version>8.0.23</version>
        </dependency>

        <dependency>
            <groupId>redis.clients</groupId>
            <artifactId>jedis</artifactId>
            <version>2.9.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.47</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.2</version>
            <scope>provided</scope>
        </dependency>
    </dependencies>

    <build>
        <sourceDirectory>src/main/scala</sourceDirectory>
        <plugins>
            <!-- 指定编译java的插件 -->
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.5.1</version>
            </plugin>
            <!-- 指定编译scala的插件 -->
            <plugin>
                <groupId>net.alchim31.maven</groupId>
                <artifactId>scala-maven-plugin</artifactId>
                <version>3.2.2</version>
                <executions>
                    <execution>
                        <goals>
                            <goal>compile</goal>
                            <goal>testCompile</goal>
                        </goals>
                        <configuration>
                            <args>
                                <arg>-dependencyfile</arg>
                                <arg>${project.build.directory}/.scala_dependencies</arg>
                            </args>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-surefire-plugin</artifactId>
                <version>2.18.1</version>
                <configuration>
                    <useFile>false</useFile>
                    <disableXmlReport>true</disableXmlReport>
                    <includes>
                        <include>**/*Test.*</include>
                        <include>**/*Suite.*</include>
                    </includes>
                </configuration>
            </plugin>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-shade-plugin</artifactId>
                <version>2.3</version>
                <executions>
                    <execution>
                        <phase>package</phase>
                        <goals>
                            <goal>shade</goal>
                        </goals>
                        <configuration>
                            <filters>
                                <filter>
                                    <artifact>*:*</artifact>
                                    <excludes>
                                        <exclude>META-INF/*.SF</exclude>
                                        <exclude>META-INF/*.DSA</exclude>
                                        <exclude>META-INF/*.RSA</exclude>
                                    </excludes>
                                </filter>
                            </filters>
                            <transformers>
                                <transformer
                                        implementation="org.apache.maven.plugins.shade.resource.ManifestResourceTransformer">
                                    <mainClass></mainClass>
                                </transformer>
                            </transformers>
                        </configuration>
                    </execution>
                </executions>
            </plugin>
        </plugins>
    </build>
</project>

注：pom依赖在业务实施中是极其重要的一环，相当于配置文件，例如可能需要的 jar 包，可能需要的 Scala 语言版本都在此处进行配置等等

创建数据库

CREATE TABLE `data` (
  `id` int(11) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL,
  `age` int(11) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB DEFAULT CHARSET=utf8;

业务逻辑

1、创建本地环境，并设置日志提示级别

val conf: SparkConf = new SparkConf().setAppName("spark").setMaster("local[*]")
val sc: SparkContext = new SparkContext(conf)
sc.setLogLevel("WARN")

2、加载数据，创建RDD

val dataRDD: RDD[(String, Int)] = sc.makeRDD(List(("tuomasi", 21), ("孙悟空", 19), ("猪八戒", 20)))

3、分区迭代

dataRDD.foreachPartition(iter => {
})

4、加载驱动

val conn: Connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/bigdata?characterEncoding=UTF-8", "root", "123456")

5、封装SQL语句

val sql: String = "INSERT INTO `data` (`id`, `name`, `age`) VALUES (NULL, ?, ?);"

val ps: PreparedStatement = conn.prepareStatement(sql)

6、数据处理

iter.foreach(t => { //t就表示每一条数据
val name: String = t._1
val age: Int = t._2
ps.setString(1, name)
ps.setInt(2, age)
ps.addBatch()
})
ps.executeBatch()

7、关闭连接

if (conn != null) conn.close()
if (ps != null) ps.close()

8、读取数据库

val getConnection = () => DriverManager.getConnection("jdbc:mysql://localhost:3306/bigdata?characterEncoding=UTF-8", "root", "123456")

9、SQL语句上下界设定以及分区数设置

val studentTupleRDD: JdbcRDD[(Int, String, Int)] = new JdbcRDD[(Int, String, Int)](
      sc,
      getConnection,
      sql,
      1,      //id为1~20之间的记录进行提取
      20,
      1,
      mapRow
    )

10、结果集处理函数

val mapRow: ResultSet => (Int, String, Int) = (r: ResultSet) => {
      val id: Int = r.getInt("id")
      val name: String = r.getString("name")
      val age: Int = r.getInt("age")
      (id, name, age)
    }

11、遍历打印数据

studentTupleRDD.foreach(println)

完整代码

package org.example.spark

import java.sql.{Connection, DriverManager, PreparedStatement, ResultSet}

import org.apache.spark.rdd.{JdbcRDD, RDD}
import org.apache.spark.{SparkConf, SparkContext}

object RDD_DataSource {
  def main(args: Array[String]): Unit = {
    //TODO 0.env/创建环境
    val conf: SparkConf = new SparkConf().setAppName("spark").setMaster("local[*]")
    val sc: SparkContext = new SparkContext(conf)
    sc.setLogLevel("WARN")

    //TODO 1.source/加载数据/创建RDD
    //RDD[(姓名, 年龄)]
    val dataRDD: RDD[(String, Int)] = sc.makeRDD(List(("tuomasi", 21), ("孙悟空", 19), ("猪八戒", 20)))

    //TODO 2.transformation
    //TODO 3.sink/输出
    //需求:将数据写入到MySQL,再从MySQL读出来
    dataRDD.foreachPartition(iter => {
      //加载驱动
      val conn: Connection = DriverManager.getConnection("jdbc:mysql://localhost:3306/bigdata?characterEncoding=UTF-8", "root", "123456")

      val sql: String = "INSERT INTO `data` (`id`, `name`, `age`) VALUES (NULL, ?, ?);"

      val ps: PreparedStatement = conn.prepareStatement(sql)

      iter.foreach(t => { //t就表示每一条数据
        val name: String = t._1
        val age: Int = t._2
        ps.setString(1, name)
        ps.setInt(2, age)
        ps.addBatch()
        //ps.executeUpdate()
      })
      ps.executeBatch()
      //关闭连接
      if (conn != null) conn.close()
      if (ps != null) ps.close()
    })

    //    //从MySQL读取
    val getConnection = () => DriverManager.getConnection("jdbc:mysql://localhost:3306/bigdata?characterEncoding=UTF-8", "root", "123456")
    val sql: String = "select id,name,age from data where id >= ? and id <= ?"
    val mapRow: ResultSet => (Int, String, Int) = (r: ResultSet) => {
      val id: Int = r.getInt("id")
      val name: String = r.getString("name")
      val age: Int = r.getInt("age")
      (id, name, age)
    }
    val studentTupleRDD: JdbcRDD[(Int, String, Int)] = new JdbcRDD[(Int, String, Int)](
      sc,
      getConnection,
      sql,
      1,
      20,
      1,
      mapRow
    )
    studentTupleRDD.foreach(println)
  }
}

程序运行

控制台打印

数据库查看

注：此为实验案例，在真实的场景中往往数据都是数以万计级别或者更多，优秀的代码往往体现在数据量极大的场景下，调优不失为一种升职加薪的必备技能

项目总结

总结：在代码编写过程中，难免出现知识匮乏，在遇到问题时，养成多看源码的好习惯，在以后的开发书写过程中会有事半功倍的效果，当然日志，及其 debug 的作用在开发中也不容小觑。

标签：读取数据,val,Int,apache,六十三,org,Spark,spark,String
来源： https://blog.csdn.net/m0_54925305/article/details/122579557