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();@Overridepublic 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();@Overridepublic 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());}}

运行结果图如下：