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Spring boot 工程中的异步
SpringBoot 工程中默认反对异步操作,然而咱们须要首先在启动类的下面,增加启动异步操作的注解 (@EnableAsync) 形容,代码如下:
@EnableAsync
@SpringBootApplication
public class DbpmsApplication {public static void main(String[] args) {SpringApplication.run(DbpmsApplication.class, args);
}
}
如果此时某个业务办法须要执行异步操作,能够应用 @Async 注解对办法进行形容,例如写日志的业务,要害代码如下
@Async// 次注解形容的办法为异步切入点办法
@Override
public void saveLog(SysLog sysLog) {
try {Thread.sleep(10000);
} catch (InterruptedException e) {e.printStackTrace();
}
System.out.println("findLogs.thread="+Thread.currentThread().getName());
sysLogDao.insertLog(sysLog);
}
其中,@Async 注解形容的办法,在 spring 中会认为这是一个异步切入点办法,在这个切入点办法执行时,底层会通过告诉办法获取线程池中的线程,通过池中的线程调用切入点办法(底层默认池类 ThreadPoolExecutor 类型)
简略应用 ThreadPoolExecutor 创立线程池
package com.cy;
import java.util.concurrent.*;
import java.util.concurrent.atomic.AtomicLong;
public class ThreadPoolExecutorTests {
// 创立工作队列,存储执行的工作
static BlockingQueue<Runnable> workQueue=
new ArrayBlockingQueue<>(1);
// 构建线程工厂
static ThreadFactory threadFactory=new ThreadFactory() {
// 线程前缀
private String prefix="pool-thread-task-";
// 定义一个提供自增自减机制的对象
private AtomicLong atomicLong=new AtomicLong(1);
@Override
public Thread newThread(Runnable r) {return new Thread(r, prefix+atomicLong.getAndIncrement());
}
};
public static void main(String[] args) {
// 初始化一个线程池
ThreadPoolExecutor tpool=
new ThreadPoolExecutor(1,
2,
3,
TimeUnit.SECONDS,
workQueue,
threadFactory,
new ThreadPoolExecutor.AbortPolicy());
tpool.execute(new Runnable() {
@Override
public void run() {String task=Thread.currentThread().getName()+"->task01";
System.out.println(task);
try {Thread.sleep(3000);
} catch (InterruptedException e) {e.printStackTrace();
}
}
});
tpool.execute(new Runnable() {
@Override
public void run() {String task=Thread.currentThread().getName()+"->task02";
System.out.println(task);
try{Thread.sleep(3000);}catch (Exception e){}}
});
tpool.execute(new Runnable() {
@Override
public void run() {String task=Thread.currentThread().getName()+"->task03";
System.out.println(task);
try{Thread.sleep(3000);}catch (Exception e){}}
});
tpool.execute(new Runnable() {
@Override
public void run() {String task=Thread.currentThread().getName()+"->task04";
System.out.println(task);
try{Thread.sleep(3000);}catch (Exception e){}}
});
}
}
后果:
pool-thread-task-1->task01
pool-thread-task-2->task03
pool-thread-task-1->task02// 期待 3 秒呈现
Java 多线程:彻底搞懂线程池
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