多线程的入门（二）线程实现与初步使用

1.实现Runable接口

实现Runable接口，实现run方法；

这种方式创建的线程实现类执行时需要创建Thread实例去运行该任务

示例如下：

package com.example.springbootdamo.Thread;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

public class RunnableTest implements Runnable{
    static Logger log = LogManager.getLogger();
    @Override
    public void run() {
        log.info("实现Runable接口的线程任务执行中");
    }
}

public static void runable(ThreadPoolExecutor poolExecutor) {
    //创建线程任务对象
    RunnableTest runnableTest = new RunnableTest();
    //调用方法的线程执行
    runnableTest.run();
    //线程调用
    Thread thread = new Thread(runnableTest);
    //重开线程执行
    thread.start();
    //调用方法的线程执行
    thread.run();
    //无返回值的线程池运行任务
    poolExecutor.execute(runnableTest);
    //有返回值的线程池运行任务
    Future<?> submit = poolExecutor.submit(runnableTest);
}

运行图如下：

1.继承Thread类

继承Thread类，重写run方法；直接运行run方法，调用start()，或者交由线程池执行

package com.example.springbootdamo.Thread;

import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.concurrent.TimeUnit;

/**
 * @ClassName ThreadTest
 * @Description TODO
 * @Author zoro
 * @Date 2024/4/4 22:24
 */
public class ThreadTest extends Thread{

    static Logger log = LogManager.getLogger();

    @Override
    public void run(){
        log.info(this.getName()+"继承Thread类的线程任务执行开始");
        try {
            //睡五秒
            this.sleep(5);
            log.info(this.getName()+"继承Thread类的线程任务执行了五秒钟");
        } catch (InterruptedException e) {
            e.printStackTrace();
        }
        log.info(this.getName()+"继承Thread类的线程任务执行结束");
    }

}

运行示例图如下：由日志是被那个线程所以打印的可知当前执行线程为何

3.实现Callable接口

实现Callable接口，实现call方法，利用FutureTask的构造器（入参为callable对象的实现类）创建实例，调用该对象的run方法或者直接用线程池执行该实例，FutureTask实现了RunnableFuture接口，RunnableFuture实现了Runnable与Future接口。

方法实现：

public static void callable(ThreadPoolExecutor poolExecutor) {
    CallableTest callable = new CallableTest();
    FutureTask futureTask = new FutureTask<>(callable);
    //运调用方法的线程行
    futureTask.run();
    //线程池调用
    poolExecutor.execute(futureTask);
    //线程池运行时，调用方法的线程等待返回值
    //方式一
    Future<ResponseBO> submit = poolExecutor.submit(callable);
    //方式二
    poolExecutor.submit(futureTask);
    try {
        //方式一
        ResponseBO responseBO = submit.get();
        log.info(responseBO.getReturnMessage());
        //方式二
        ResponseBO responseBO2 = (ResponseBO) futureTask.get();
        log.info(responseBO2.getReturnMessage()+"+++");
    } catch (InterruptedException e) {
        e.printStackTrace();
    } catch (ExecutionException e) {
        e.printStackTrace();
    }

运行结果：因为返回值问题，所以调用线程会等待线程执行完任务后继续执行。从下方线程池的工作任务队列workers可知三次都是重新创建的线程

4.线程池创建线程

主要是通过线程池工厂创建
public void threadPool(){
    //默认线程池工厂
    ThreadPoolExecutor poolExecutor = new ThreadPoolExecutor(5, 5, 5000, TimeUnit.SECONDS, new LinkedBlockingDeque<>());
    //自定义线程池工厂
    ThreadPoolExecutor poolExecutor1 = new ThreadPoolExecutor(5, 5, 5000, TimeUnit.SECONDS, new LinkedBlockingDeque<>(),new ThreadFactoryTest());
}
线程池创建的线程需要有执行任务对象该对象一般要实现Runable接口或者Callable接口

执行方法有 submit()和execute()两种方式，前者有返回值，后者没有返回值

示例如下：

package com.example.springbootdamo.Thread;

import com.example.springbootdamo.ResponseBO;
import org.apache.logging.log4j.LogManager;
import org.apache.logging.log4j.Logger;

import java.util.concurrent.*;

public class ThreadPoolTest {

    static Logger log = LogManager.getLogger();

    public static void main(String[] args) {
        //创建线程池
        ThreadPoolExecutor poolExecutor = new ThreadPoolExecutor(5, 5, 5000, TimeUnit.SECONDS, new LinkedBlockingDeque<>());
        callable(poolExecutor);
        runable(poolExecutor);
        thread(poolExecutor);
        log.info("日志打印测试");
    }

    public static void callable(ThreadPoolExecutor poolExecutor) {
        CallableTest callable = new CallableTest();
        FutureTask futureTask = new FutureTask<>(callable);
        //线程池调用
        poolExecutor.execute(futureTask);
        //线程池运行时，调用方法的线程等待返回值
        //方式一
        Future<ResponseBO> submit = poolExecutor.submit(callable);
        //方式二
        poolExecutor.submit(futureTask);
        try {
            //方式一
            ResponseBO responseBO = submit.get();
            log.info(responseBO.getReturnMessage());
            //方式二
            ResponseBO responseBO2 = (ResponseBO) futureTask.get();
            log.info(responseBO2.getReturnMessage()+"+++");
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            e.printStackTrace();
        }
    }


    public static void runable(ThreadPoolExecutor poolExecutor) {
        //创建线程任务对象
        RunnableTest runnableTest = new RunnableTest();
        //无返回值的线程池运行任务
        poolExecutor.execute(runnableTest);
        //有返回值的线程池运行任务
        Future<?> submit = poolExecutor.submit(runnableTest);
    }
    public static void thread(ThreadPoolExecutor poolExecutor) {
        //创建线程任务对象
        ThreadTest threadTest = new ThreadTest();
        //线程池运行任务
        poolExecutor.execute(threadTest);
        // 执行的是线程的任务
        poolExecutor.submit(threadTest, new ResponseBO());
    }

}