一、CompletableFuture
1.1 supplyAsync异步执行，不取返回值-指定线程池
代码
public class SupplyAsyncTest {
/**
* supplyAsync异步执行，不取返回值-指定线程池
*/
public static void main(String[] args) {
System.out.println(Thread.currentThread() + " 主线程-开始,time->" + getTime());
CompletableFuture.supplyAsync(() -> {
System.out.println("子线程-是否为守护线程:" + Thread.currentThread().isDaemon());
System.out.println(Thread.currentThread() + " 子线程-开始,time->" + getTime());
try {
Thread.sleep(2000);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread() + " 子线程-退出,time->" + getTime());
return "AlanChen";
}, GlobalThreadPool.getExecutor());
System.out.println(Thread.currentThread() + " 主线程-退出,time->" + getTime());
}
private static String getTime() {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");
return formatter.format(new Date());
}
}
执行结果
Thread[main,5,main] 主线程-开始,time->2022-02-16 17:58:52 557
Thread[main,5,main] 主线程-退出,time->2022-02-16 17:58:52 594
子线程-是否为守护线程:false
Thread[pool-1-thread-1,5,main] 子线程-开始,time->2022-02-16 17:58:52 595
Thread[pool-1-thread-1,5,main] 子线程-退出,time->2022-02-16 17:58:54 600
Process finished with exit code 0
supplyAsync()方法和runAsync()方法一样有守护线程的问题，因此我们调用时指定线程池，而不用默认的线程池。
1.2 supplyAsync异步执行，同步取返回值-get
代码
public class SupplyAsyncTest2 {
/**
* supplyAsync异步执行，同步取返回值
*/
public static void main(String[] args) {
System.out.println(Thread.currentThread() + " 主线程-开始,time->" + getTime());
CompletableFuture<String> completableFuture =CompletableFuture.supplyAsync(() -> {
System.out.println("子线程-是否为守护线程:" + Thread.currentThread().isDaemon());
System.out.println(Thread.currentThread() + " 子线程-开始,time->" + getTime());
try {
Thread.sleep(2000);
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread() + " 子线程-退出,time->" + getTime());
return "AlanChen";
}, GlobalThreadPool.getExecutor());
// 中间可以先执行一堆逻辑，再阻塞获取返回结果
System.out.println("中间可以先执行一堆逻辑，再阻塞获取返回结果");
try {
//阻塞获取返回结果
System.out.println("异步执行返回结果:" + completableFuture.get());
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread() + " 主线程-退出,time->" + getTime());
}
private static String getTime() {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");
return formatter.format(new Date());
}
}
执行结果
Thread[main,5,main] 主线程-开始,time->2022-02-16 18:02:45 956
中间可以先执行一堆逻辑，再阻塞获取返回结果
子线程-是否为守护线程:false
Thread[pool-1-thread-1,5,main] 子线程-开始,time->2022-02-16 18:02:46 000
Thread[pool-1-thread-1,5,main] 子线程-退出,time->2022-02-16 18:02:48 008
异步执行返回结果:AlanChen
Thread[main,5,main] 主线程-退出,time->2022-02-16 18:02:48 009
1.3 supplyAsync异步执行，异步取返回值-whenCompleteAsync
代码
public class SupplyAsyncTest3 {
/**
* supplyAsync异步执行，异步取返回值
*/
public static void main(String[] args) {
System.out.println(Thread.currentThread() + " 主线程-开始,time->" + getTime());
CompletableFuture<String> completableFuture = CompletableFuture.supplyAsync(() -> {
System.out.println("子线程-是否为守护线程:" + Thread.currentThread().isDaemon());
System.out.println(Thread.currentThread() + " 子线程-开始,time->" + getTime());
try {
Thread.sleep(2000);
} catch (Exception e) {
e.printStackTrace();
}
//int a=1/0;
System.out.println(Thread.currentThread() + " 子线程-退出,time->" + getTime());
return "AlanChen";
}, GlobalThreadPool.getExecutor());
// 中间可以执行一堆逻辑
System.out.println("中间可以执行一堆逻辑");
//异步回调获取返回值
completableFuture.whenCompleteAsync((result, e) -> {
System.out.println("-------异步执行返回结果:" + result);
System.out.println("-------e=" + e);
}).exceptionally(f -> {
System.out.println("-----exception:" + f.getMessage());
return "出现异常后的返回值";
});
System.out.println(Thread.currentThread() + " 主线程-退出,time->" + getTime());
}
private static String getTime() {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");
return formatter.format(new Date());
}
}
执行结果
Thread[main,5,main] 主线程-开始,time->2022-02-16 18:12:45 109
中间可以执行一堆逻辑
子线程-是否为守护线程:false
Thread[pool-1-thread-1,5,main] 子线程-开始,time->2022-02-16 18:12:45 149
Thread[main,5,main] 主线程-退出,time->2022-02-16 18:12:45 150
Thread[pool-1-thread-1,5,main] 子线程-退出,time->2022-02-16 18:12:47 159
-------异步执行返回结果:AlanChen
-------e=null
二、Future
2.1 Future异步执行，不需要取返回值
代码
public class FutureTest {
/**
* Future异步执行，不需要取返回值
*/
public static void main(String[] args) {
System.out.println(Thread.currentThread() + " 主线程-开始,time->" + getTime());
ExecutorService executor = Executors.newFixedThreadPool(3);
executor.submit(() -> {
System.out.println("子线程-是否为守护线程:" + Thread.currentThread().isDaemon());
System.out.println(Thread.currentThread() + " 子线程-开始,time->" + getTime());
Thread.sleep(2000);
System.out.println(Thread.currentThread() + " 子线程-退出,time->" + getTime());
return "AlanChen";
});
System.out.println(Thread.currentThread() + " 主线程-退出,time->" + getTime());
}
private static String getTime() {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");
return formatter.format(new Date());
}
}
执行结果
Thread[main,5,main] 主线程-开始,time->2022-02-16 16:44:29 719
子线程-是否为守护线程:false
Thread[main,5,main] 主线程-退出,time->2022-02-16 16:44:29 756
Thread[pool-1-thread-1,5,main] 子线程-开始,time->2022-02-16 16:44:29 756
Thread[pool-1-thread-1,5,main] 子线程-退出,time->2022-02-16 16:44:31 761
2.2 Future异步执行，取返回值
代码
public class FutureTest2 {
/**
* Future异步执行，取返回值
*/
public static void main(String[] args) {
System.out.println(Thread.currentThread() + " 主线程-开始,time->" + getTime());
ExecutorService executor = Executors.newFixedThreadPool(3);
Future future = executor.submit(() -> {
System.out.println("子线程-是否为守护线程:" + Thread.currentThread().isDaemon());
System.out.println(Thread.currentThread() + " 子线程-开始,time->" + getTime());
Thread.sleep(2000);
System.out.println(Thread.currentThread() + " 子线程-退出,time->" + getTime());
return "AlanChen";
});
// 中间可以先执行一堆逻辑，再阻塞获取返回结果
System.out.println("中间可以先执行一堆逻辑，再阻塞获取返回结果");
try {
//阻塞获取返回结果
System.out.println("异步执行返回结果:" + future.get());
} catch (Exception e) {
e.printStackTrace();
}
System.out.println(Thread.currentThread() + " 主线程-退出,time->" + getTime());
}
private static String getTime() {
SimpleDateFormat formatter = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss SSS");
return formatter.format(new Date());
}
}
执行结果
Thread[main,5,main] 主线程-开始,time->2022-02-16 16:49:19 027
中间可以先执行一堆逻辑，再阻塞获取返回结果
子线程-是否为守护线程:false
Thread[pool-1-thread-1,5,main] 子线程-开始,time->2022-02-16 16:49:19 070
Thread[pool-1-thread-1,5,main] 子线程-退出,time->2022-02-16 16:49:21 079
异步执行返回结果:AlanChen
Thread[main,5,main] 主线程-退出,time->2022-02-16 16:49:21 080
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