Java中创建线程的三种方式及其优缺点

1.自定义一个继承Thread的类，由于Java的单继承特性，限制了该类的扩展性。

2.实现Runnable接口，重写run()方法。

3.实现Callable接口，重写call方法。线程执行体可以有返回值，并且可以抛出异常。

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

public class Main {
    public static void main(String[] args) {
        // 1.继承Thread类
        new DefineThread().start();
        // 2.实现Runnable接口
        new Thread(new DefineRunnable()).start();
        // 3.实现Callable接口
        new Thread(futureTask).start();
        String result = "";
        try {
            result = futureTask.get();
        } catch (InterruptedException e) {
            e.printStackTrace();
        } catch (ExecutionException e) {
            //ExecutionException封装了call()方法抛出的异常
            e.printStackTrace();
            e.getCause();
            //getCause()方法把被包装的原始异常提取出来
        }
        System.out.println(result);
    }

    static class DefineThread extends Thread {

        @Override
        public void run() {
            for (int i = 0; i < 100; i++) {
                String name2 = getName();
                try {
                    sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(name2 + ": " + i);
            }
        }
    }

    static class DefineRunnable implements Runnable {

        @Override
        public void run() {
            for (int i = 0; i < 100; i++) {
                // String name2 = getName();
                String name = Thread.currentThread().getName(); // 实现runnable接口，使用Thread类的currentThread()获取当前线程对象
                try {
                    Thread.currentThread().sleep(100);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
                System.out.println(name + ": " + i);
            }
        }
    }

    static FutureTask<String> futureTask = new FutureTask<>(new Callable<String>() {

        @Override
        public String call() throws InterruptedException {
            String name = "";
            int i = 0;
            for (; i < 100; i++) {
                name = Thread.currentThread().getName();
                Thread.currentThread().sleep(100);
                System.out.println(name + ": " + i);
            }
            return name + " ----->Result=" + i;
        }
    });
}