spring boot using asynchronous tasks @Async

Disclaimer: This article is a blogger original article, please indicate the source. Welcome to public concern number: Java Notes Share (xiaosen_javashare) https://blog.csdn.net/qq_36447151/article/details/87362013

github project Address: https://github.com/lgsdaredevil/asyncTest

Open asynchronous tasks

Add @EnableAsync notes in the application main class

Write asynchronous task methods

	@Async
    public Future<String> ansync(String name){
        try {
            Thread.sleep(10000);
            logger.info("这里是异步方法");
            logger.info("传过来的名字是：" + name);
            name = "修改的名字";
            logger.info("修改后的名字是：" + name);
            return new AsyncResult<>("name: " + name);
        }catch (Exception e){
            return new AsyncResult<>("异常");
        }
    }

Asynchronous method call

• 1, by acquiring the return value Future

public String requestAnsync(String name){
        try {
            Long start = System.currentTimeMillis();
            Future<String> result = ansync(name);
            if (result.isDone()){
                name = result.get();
                logger.info("异步方法结束，名字改为：" + name);
            }
            Long end = System.currentTimeMillis();
            logger.info("耗时：" + (int)(end-start));
            return "hello " + name;
        }catch (Exception e){
            logger.error("异常");
            return "异常";
        }
    }

If you want to get a return value, you should get the polling method, otherwise it will not go Ruoguo no isDone the following methods, or you can use CompletableFuture:

2018-07-17 11:31:55.390  INFO 5232 --- [nio-8080-exec-6] c.e.async.service.AsyncTestService       : 耗时：0
2018-07-17 11:32:05.394  INFO 5232 --- [cTaskExecutor-3] com.example.async.service.AsyncTest      : 这里是异步方法
2018-07-17 11:32:05.394  INFO 5232 --- [cTaskExecutor-3] com.example.async.service.AsyncTest      : 传过来的名字是：ling
2018-07-17 11:32:05.394  INFO 5232 --- [cTaskExecutor-3] com.example.async.service.AsyncTest      : 修改后的名字是：修改的名字

If you use future.get () method blocks the thread until I got the results.

• 2, do not use Future.get () method, asynchronous method is not used to return Future

    @Async
    public void noReturnAsync(String name){
        try {
            Thread.sleep(10000);
            logger.info("这里是异步方法");
            logger.info("传过来的名字是：" + name);
            name = "修改的名字";
            logger.info("修改后的名字是：" + name);
        }catch (Exception e){
        }
    }

Asynchronous method call

public String noReturn(String name){
        Long start = System.currentTimeMillis();
        asyncTest.noReturnAsync(name);
        Long end = System.currentTimeMillis();
        logger.info("耗时：" + (int)(end-start));
        return "hello " + name;
    }

Note specific region:

If the asynchronous method to synchronous method blocks, possibly because of the asynchronous method calls and ordinary methods in the same class, the solution is an asynchronous method into a separate class.
Reason: When spring when @Transactional for annotation have similar problems, have @Transactional annotation classes when spring scanning method, is to generate a proxy class by proxy class to open and close the transaction, while in the same class, method calls in , spring can not intercept the call to execute the method of the class body.
Referring specifically: the Spring @Async asynchronous call using the Boot