java创建线程的四种方式

java创建线程的三种方式

1. 继承Thread类创建线程类

package com.thread;
public class FirstThreadTest extends Thread{
int i = 0;
//重写run方法，run方法的方法体就是现场执行体
public void run()
{
for(;i<100;i++){
System.out.println(getName()+" "+i);
}
}
public static void main(String[] args)
{
for(int i = 0;i< 100;i++)
{
System.out.println(Thread.currentThread().getName()+" : "+i);
if(i==20)
{
new FirstThreadTest().run();
new FirstThreadTest().run();
}
}
}
}

2. 通过Runable接口创建线程类

package com.thread;
public class RunnableThreadTest implements Runnable
{
private int i;
public void run()
{
for(i = 0;i <100;i++)
{
System.out.println(Thread.currentThread().getName()+" "+i);
}
}
public static void main(String[] args)
{
for(int i = 0;i < 100;i++)
{
System.out.println(Thread.currentThread().getName()+" "+i);
if(i==20)
{
RunnableThreadTest rtt = new RunnableThreadTest();
new Thread(rtt,"新线程1").start();
new Thread(rtt,"新线程2").start();
}
}
}
}

3. 通过Callable和FutureTask创建线程

   a. 创建Callable接口的实现类，并实现call()方法；
   b. 创建Callable实现类的实例，使用FutureTask类来包装Callable对象，该FutureTask对象封装了该Callback对象的call()方法的返回值；
   c. 使用FutureTask对象作为Thread对象的target创建并启动新线程；

d. 调用FutureTask对象的get()方法来获得子线程执行结束后的返回值。

[java] view plain copy

package com.demo;
import java.util.concurrent.Callable;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;
public class CallableThreadTest implements Callable<Integer>
{
public static void main(String[] args)
{
CallableThreadTest ctt = new CallableThreadTest();
FutureTask<Integer> ft = new FutureTask<Integer>(ctt);
// Thread thread = new Thread(ft,"有返回值的线程");
// thread.start();
for(int i = 0;i < 100;i++)
{
System.out.println(Thread.currentThread().getName()+" 的循环变量i的值"+i);
if(i==20)
{
new Thread(ft,"有返回值的线程").start();
}
}
try
{
System.out.println("子线程的返回值："+ft.get());
} catch (InterruptedException e)
{
e.printStackTrace();
} catch (ExecutionException e)
{
e.printStackTrace();
}
}
@Override
public Integer call() throws Exception
{
int i = 0;
for(;i<100;i++)
{
System.out.println(Thread.currentThread().getName()+" "+i);
}
return i;
}
}

4. 通过线程池创建线程

[java] view plain copy

/**
*
*/
package com.demo;
import java.util.concurrent.ExecutorService;
import java.util.concurrent.Executors;
/**
* @author Maggie
*
*/
public class ThreadPool
{
/* POOL_NUM */
private static int POOL_NUM = 10;
/**
* Main function
*/
public static void main(String[] args)
{
ExecutorService executorService = Executors.newFixedThreadPool(5);
for(int i = 0; i<POOL_NUM; i++)
{
RunnableThread thread = new RunnableThread();
executorService.execute(thread);
}
}
}
class RunnableThread implements Runnable
{
private int THREAD_NUM = 10;
public void run()
{
for(int i = 0; i<THREAD_NUM; i++)
{
System.out.println("线程" + Thread.currentThread() + " " + i);
}
}
}

java创建线程的四种方式

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