1.继承Thread类创建线程
- 定义Thread类的子类,并重写该类的run()方法,该方法的方法体就是线程需要完成的任务,run()方法也称为线程执行体
- 创建Thread子类的实例,也就是创建了线程对象
- 启动线程,即调用线程的start()方法
package com.practise.thread;
public class InheritThread extends Thread {
@Override
public void run() {
for (int i = 1; i <= 20; i++) {
System.out.println(Thread.currentThread().getName() + ":" + i);
}
}
}
package com.practise.thread;
public class ThreadTest {
public static void main(String[] args) {
//线程类
InheritThread inheritThread = new InheritThread();
inheritThread.setName("线程一");//设置线程名称
inheritThread.start();
//主线程
Thread.currentThread().setName("主线程");
for (int i = 1; i <= 20; i++) {
System.out.println(Thread.currentThread().getName() + ":" + i);
}
}
}
2.实现Runnable接口创建线程
- 定义Runnable接口的实现类,一样要重写run()方法,这个run()方法和Thread中的run()方法一样是线程的执行体
- 创建Runnable实现类的实例,并用这个实例作为Thread的target来创建Thread对象,这个Thread对象才是真正的线程对象
- 调用线程对象的start()方法来启动线程
package com.practise.thread;
public class ImplementRunnable implements Runnable {
@Override
public void run() {
for (int i = 1; i <= 20; i++) {
System.out.println(Thread.currentThread().getName() + ":" + i);
}
}
}
package com.practise.thread;
public class ThreadTest {
public static void main(String[] args) {
//实现Runnable接口
ImplementRunnable implementRunnable=new ImplementRunnable();
Thread thread=new Thread(implementRunnable);
thread.setName("线程二");
thread.start();
//主线程
Thread.currentThread().setName("主线程");
for (int i = 1; i <= 20; i++) {
System.out.println(Thread.currentThread().getName() + ":" + i);
}
}
}
3.使用Callable和Future创建线程
- 创建Callable接口的实现类,并实现call()方法,然后创建该实现类的实例(从java8开始可以直接使用Lambda表达式创建Callable对象)
- 使用FutureTask类来包装Callable对象,该FutureTask对象封装了Callable对象的call()方法的返回值
- 使用FutureTask对象作为Thread对象的target创建并启动线程(因为FutureTask实现了Runnable接口)
- 调用FutureTask对象的get()方法来获得子线程执行结束后的返回值
package com.practise.createthread;
import java.util.concurrent.Callable;
public class ImplementCallable implements Callable<Integer> {
@Override
public Integer call() {
Integer total = 0;
try {
for (int i = 1; i <= 50; i++) {
total += i;
}
return total;
} catch (Exception ex) {
ex.printStackTrace();
}
return null;
}
}
package com.practise.createthread;
import java.util.concurrent.ExecutionException;
import java.util.concurrent.FutureTask;
public class ThreadTest {
public static void main(String[] args) {
ImplementCallable implementCallable=new ImplementCallable();
FutureTask<Integer> task=new FutureTask<Integer>(implementCallable);
Thread thread=new Thread(task,"有返回值的线程");
thread.start();
try {
System.out.println(task.get());
} catch (Exception ex) {
ex.printStackTrace();
}
Thread.currentThread().setName("主线程");
for (int i = 1; i <= 20; i++) {
System.out.println(Thread.currentThread().getName() + ":" + i);
}
}
}