CountDownLatch 部分加载和同时并发业务。

按顺序部分加载：

import java.util.concurrent.CountDownLatch;

/**
 * @Title: ThreadCountDownTest.java
 * @Description:
 * @author: wuwenjie
 * @date: 2019.07.17 16:43
 *
 */
public class ThreadCountDownTest {

    public static void main(String[] args) {
// 初始化闭锁，并设置资源个数
        CountDownLatch latch = new CountDownLatch(2);

        Thread t1 =new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(1000);
　　　　　　　　　　　　//加载1
                    latch.countDown();
                    System.out.println(111);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });

        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(12000);
　　　　　　　　　　　　//加载2
                    latch.countDown();
                    System.out.println(222);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });

        Thread t3 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
　　　　　　　　　　　　
                    latch.await();
　　　　　　　　　　　　　//加载完成业务使用
                    System.out.println(333);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });
        t1.start();
        t2.start();
        t3.start();

    }

}

2.同时业务并发处

import java.util.concurrent.CountDownLatch;

public class ThreadCountDownTest {

    public static void main(String[] args) {
// 初始化闭锁，并设置资源个数
        CountDownLatch latch = new CountDownLatch(2);

        Thread t1 =new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(1000);
                    latch.countDown();
　　　　　　　　　　　　//等待所有执行完，并发
                    latch.await();
                    System.out.println(111);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });

        Thread t2 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    Thread.sleep(12000);
                    latch.countDown();
                    latch.await();
                    System.out.println(222);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });

        Thread t3 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    latch.await();
                    System.out.println(333);
                } catch (InterruptedException e) {
                    e.printStackTrace();
                }
            }
        });
        t1.start();
        t2.start();
        t3.start();

    }

}