Spring Boot中线程池使用

说明：在一些场景，如导入数据，批量插入数据库，使用常规方法，需要等待较长时间，而使用线程池可以提高效率。本文介绍如何在Spring Boot中使用线程池来批量插入数据。

搭建环境

首先，创建一个Spring Boot项目，pom文件如下：

<?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>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>2.7.12</version>
        <relativePath/>
    </parent>

    <groupId>com.hezy</groupId>
    <artifactId>thread_pool_demo</artifactId>
    <version>1.0-SNAPSHOT</version>

    <properties>
        <maven.compiler.source>11</maven.compiler.source>
        <maven.compiler.target>11</maven.compiler.target>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-web</artifactId>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>druid-spring-boot-starter</artifactId>
            <version>1.2.8</version>
        </dependency>

        <dependency>
            <groupId>com.mysql</groupId>
            <artifactId>mysql-connector-j</artifactId>
            <scope>runtime</scope>
        </dependency>

        <dependency>
            <groupId>org.mybatis.spring.boot</groupId>
            <artifactId>mybatis-spring-boot-starter</artifactId>
            <version>2.2.2</version>
        </dependency>

        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter-test</artifactId>
            <scope>test</scope>
        </dependency>

        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.8.6</version>
        </dependency>
    </dependencies>
</project>

写一个插入数据的Mapper方法

java">import com.hezy.pojo.User;
import org.apache.ibatis.annotations.Insert;
import org.apache.ibatis.annotations.Mapper;
import org.apache.ibatis.annotations.Param;

@Mapper
public interface UserMapper {

    @Insert("insert into i_users (username, password) values (#{user.username}, #{user.password})")
    void insert(@Param("user") User user);
}

写一个接口，用来插入20万条记录，如下：

java">import com.hezy.pojo.User;
import com.hezy.service.AsyncService;
import com.hezy.service.UserService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

import java.util.ArrayList;

@RestController
@RequestMapping("user")
public class UserController {

    /**
     * 总记录数
     */
    private final static int SIZE = 40 * 10000;

    @Autowired
    private UserService userService;

    @Autowired
    private AsyncService asyncService;

    @GetMapping("insert1")
    public void insert1() {
        ArrayList<User> list = new ArrayList<>(SIZE);
        for (int i = 0; i < SIZE; i++) {
            User user = new User();
            user.setUsername("user" + i);
            user.setPassword("password" + i);
            list.add(user);
        }

        long startTime = System.currentTimeMillis();
        // 批量插入
        for (User user : list) {
            userService.insert(user);
        }
        long endTime = System.currentTimeMillis();
        System.out.println("不用线程池===插入40万条记录耗时:" + ((endTime - startTime) / 1000) + "s");
    }
}

启动项目，测试一下，看要多长时间……11分钟

在这里插入图片描述

使用线程池

Spring Boot有自动注入的线程池（threadPoolTaskExecutor），可以手动设置一些属性，为我们所用。

java">import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

@Configuration
@EnableAsync
public class ThreadPoolConfig {

    @Bean(name = "threadPoolTaskExecutor")
    public Executor threadPoolTaskExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setCorePoolSize(20);
        executor.setMaxPoolSize(40);
        executor.setQueueCapacity(500);
        executor.setKeepAliveSeconds(60);
        executor.setThreadNamePrefix("hezy-");
        executor.setRejectedExecutionHandler(new ThreadPoolExecutor.CallerRunsPolicy());
        executor.initialize();
        return executor;
    }
}

使用线程池来完成上面插入数据的操作，如下：

java">    @GetMapping("insert2")
    public void insert2() {
        ArrayList<User> list = new ArrayList<>(SIZE);
        for (int i = 0; i < SIZE; i++) {
            User user = new User();
            user.setUsername("user" + i);
            user.setPassword("password" + i);
            list.add(user);
        }
        // 将数据分成4000批，每批插入100条
        List<List<User>> batchList = new ArrayList<>();
        for (int i = 0; i < list.size(); i += 100) {
            batchList.add(list.subList(i, i + 100));
        }

        long startTime = System.currentTimeMillis();
        CountDownLatch countDownLatch = new CountDownLatch(batchList.size());
        // 线程池分批插入
        for (List<User> batch : batchList) {
            asyncService.executeAsync(batch, userService, countDownLatch);
        }
        try {
            countDownLatch.await();
        } catch (InterruptedException e) {
            throw new RuntimeException(e);
        }
        long endTime = System.currentTimeMillis();
        System.out.println("使用线程池===插入40万条记录耗时:" + ((endTime - startTime) / 1000) + "s");
    }

AsyncService实现类

java">import com.hezy.pojo.User;
import com.hezy.service.AsyncService;
import com.hezy.service.UserService;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

import java.util.List;
import java.util.concurrent.CountDownLatch;

@Service
public class AsyncServiceImpl implements AsyncService {

    @Async("threadPoolTaskExecutor")
    @Override
    public void executeAsync(List<User> batch, UserService userService, CountDownLatch countDownLatch) {
        try {
            for (User user : batch) {
                userService.insert(user);
            }
        } finally {
            countDownLatch.countDown();
        }
    }
}