使用SPRING中的线程池ThreadPoolTaskExecutor实现JAVA并发

使用SPRING中的线程池ThreadPoolTaskExecutor实现JAVA并发

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• Java

SpringJava多线程JDKthread

使用SPRING中的线程池ThreadPoolTaskExecutor实现并发。

一：不需要返回值的情况
1，初始化线程池

ThreadPoolTaskExecutor poolTaskExecutor = new ThreadPoolTaskExecutor();
poolTaskExecutor.setQueueCapacity(10000);
poolTaskExecutor.setCorePoolSize(5);
poolTaskExecutor.setMaxPoolSize(10);
poolTaskExecutor.setKeepAliveSeconds(5000);
poolTaskExecutor.initialize();

ThreadPoolTaskExecutor poolTaskExecutor = new ThreadPoolTaskExecutor();
poolTaskExecutor.setQueueCapacity(10000);
poolTaskExecutor.setCorePoolSize(5);
poolTaskExecutor.setMaxPoolSize(10);
poolTaskExecutor.setKeepAliveSeconds(5000);
poolTaskExecutor.initialize();

 

2，在线程池中执行某个线程

poolTaskExecutor.execute(new Thread(Objct...){...});

poolTaskExecutor.execute(new Thread(Objct...){...});

 

二：需要返回值的情况
1，初始化线程池poolTaskExecutor，同上

 

2，新建一个类，实现Callable接口

class GetFromDB implements Callable<User> {
private UserDao userDao;
private Long userId;

public GetFromDB(UserDao userDao, Long userId) {
this.userDao = userDao;
this.userId = userId;
}

public User call() throws DaoException {
User user = userDao.getUserById(userId);
return user;
}
}

class GetFromDB implements Callable<User> {
    private UserDao userDao;
    private Long userId;

    public GetFromDB(UserDao userDao, Long userId) {
        this.userDao = userDao;
        this.userId = userId;
    }

    public User call() throws DaoException {
        User user = userDao.getUserById(userId);
        return user;
    }
}

 

3，用之前的GetFromDB类构造一个FutureTask类

FutureTask<User> dbtask = new FutureTask<User>(GetFromDB);

FutureTask<User> dbtask = new FutureTask<User>(GetFromDB);

 

4，提交并执行

threadpool.submit(dbtask);

threadpool.submit(dbtask);

 

5，得到返回值

try {
User user = dbtask.get();
} catch (Exception e) {
if (e instanceof ExecutionException
&& ((ExecutionException) e).getCause() instanceof DaoException) {
throw (DaoException) ((ExecutionException) e).getCause();
} else {
其他处理方式
}
}

try {
    User user = dbtask.get();
} catch (Exception e) {
    if (e instanceof ExecutionException
            && ((ExecutionException) e).getCause() instanceof DaoException) {
        throw (DaoException) ((ExecutionException) e).getCause();
    } else {
        其他处理方式
    }
}

 

注：一旦调用了get()方法，如果线程还未产生返回值，则将阻塞get()方法，直到得到返回值。基于此，如果你想确保线程执行完后才执行下一步操作，即使你不想得到返回值也可以调用一下此方法。当然这与多线程的初衷不符。