Java创建多线程的几种方式实现

//方式1
package cn.itcats.thread.Test1;

public class Demo1 extends Thread{
 
 //重写的是父类Thread的run()
 public void run() {
  System.out.println(getName()+"is running...");
 }
 
 
 public static void main(String[] args) {
  Demo1 demo1 = new Demo1();
  Demo1 demo2 = new Demo1();
  demo1.start();
  demo2.start();
 }
}

//Thread类源码中的run()方法
//target为Thread 成员变量中的 private Runnable target;

 @Override
 public void run() {
  if (target != null) {
   target.run();
  }
 }

package cn.itcats.thread.Test1;

/**
 * 第二种创建启动线程的方式
 * 实现Runnale接口
 * @author fatah
 */
public class Demo2 implements Runnable{

  //重写的是Runnable接口的run()
  public void run() {
      System.out.println("implements Runnable is running");
  }
  
  public static void main(String[] args) {
    Thread thread1 = new Thread(new Demo2());
    Thread thread2 = new Thread(new Demo2());
    thread1.start();
    thread2.start();
  }

 
}

package cn.itcats.thread.Test1;
/**
 * 创建启动线程的第三种方式————匿名内部类
 * @author fatah
 */
public class Demo3 {
  public static void main(String[] args) {
    //方式1：相当于继承了Thread类，作为子类重写run()实现
    new Thread() {
      public void run() {
        System.out.println("匿名内部类创建线程方式1...");
      };
    }.start();
    
    
    
    //方式2:实现Runnable,Runnable作为匿名内部类
    new Thread(new Runnable() {
      public void run() {
        System.out.println("匿名内部类创建线程方式2...");
      }
    } ).start();
  }
}

package cn.itcats.thread.Test1;

import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;
import java.util.concurrent.FutureTask;
import java.util.concurrent.RunnableFuture;

/**
 * 方式4:实现Callable<T> 接口
 * 含返回值且可抛出异常的线程创建启动方式
 * @author fatah
 */
public class Demo5 implements Callable<String>{

  public String call() throws Exception {
    System.out.println("正在执行新建线程任务");
    Thread.sleep(2000);
    return "新建线程睡了2s后返回执行结果";
  }

  public static void main(String[] args) throws InterruptedException, ExecutionException {
    Demo5 d = new Demo5();
    /*  call()只是线程任务,对线程任务进行封装
      class FutureTask<V> implements RunnableFuture<V>
      interface RunnableFuture<V> extends Runnable, Future<V>
    */
    FutureTask<String> task = new FutureTask<>(d);
    Thread t = new Thread(task);
    t.start();
    System.out.println("提前完成任务...");
    //获取任务执行后返回的结果
    String result = task.get();
    System.out.println("线程执行结果为"+result);
  }
  
}

package cn.itcats.thread.Test1;

import java.util.Timer;
import java.util.TimerTask;

/**
 * 方法5：创建启动线程之Timer定时任务
 * @author fatah
 */
public class Demo6 {
  public static void main(String[] args) {
    Timer timer = new Timer();
    timer.schedule(new TimerTask() {
      @Override
      public void run() {
        System.out.println("定时任务延迟0(即立刻执行),每隔1000ms执行一次");
      }
    }, 0, 1000);
  }
  
}

package cn.itcats.thread.Test1;

import java.util.concurrent.Executor;
import java.util.concurrent.Executors;

public class Demo7 {
  public static void main(String[] args) {
    //创建带有5个线程的线程池
    //返回的实际上是ExecutorService,而ExecutorService是Executor的子接口
    Executor threadPool = Executors.newFixedThreadPool(5);
    for(int i = 0 ;i < 10 ; i++) {
      threadPool.execute(new Runnable() {
        public void run() {
          System.out.println(Thread.currentThread().getName()+" is running");
        }
      });
    }
    
  }
}

package cn.itcats.thread.Test1;

import java.util.ArrayList;
import java.util.Arrays;
import java.util.List;

/**
 * 使用Lambda表达式并行计算
 * parallelStream
 * @author fatah
 */
public class Demo8 {
  public static void main(String[] args) {
    List<Integer> list = Arrays.asList(1,2,3,4,5,6);
    Demo8 demo = new Demo8();
    int result = demo.add(list);
    System.out.println("计算后的结果为"+result);
  }
  
  public int add(List<Integer> list) {
    //若Lambda是串行执行,则应顺序打印
    list.parallelStream().forEach(System.out :: println);
    //Lambda有stream和parallelSteam(并行)
    return list.parallelStream().mapToInt(i -> i).sum();
  }
}

package cn.itcats.thread;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.annotation.EnableAsync;

@Configuration
@ComponentScan("cn.itcats.thread")
@EnableAsync
public class Config {
  
}

package cn.itcats.thread;

import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;

@Service
public class AsyncService {
  
  @Async
  public void Async_A() {
    System.out.println("Async_A is running");
  }
  
  @Async
  public void Async_B() {
    System.out.println("Async_B is running");
  }
}

package cn.itcats.thread;

import org.springframework.context.annotation.AnnotationConfigApplicationContext;

public class Run {
  public static void main(String[] args) {
    //构造方法传递Java配置类Config.class
    AnnotationConfigApplicationContext ac = new AnnotationConfigApplicationContext(Config.class);
    AsyncService bean = ac.getBean(AsyncService.class);
    bean.Async_A();
    bean.Async_B();
  }
}