Spring4的@configure
1,生成自定义的bean，纳入spring管理
2,覆盖默认的同名bean
3,对于集成抽象类或实现接口的，这个实现类就是代替默认抽象类或接口
下面以异步线程为例：
本文记录@Async的基本使用以及通过实现ThreadFactory来实现对线程的命名。
@Async的基本使用
业务场景需要进行批量更新，已有数据id主键、更新的状态。单条更新性能太慢，所以使用in进行批量更新。但是会导致锁表使得其他业务无法访问该表，in的量级太低又导致性能太慢。
龙道友提出了一个解决方案，把要处理的数据分成几个list之后使用多线程进行数据更新。提到多线程可直接使用@Async注解来进行异步操作。
好的，接下来上面的问题我们不予解答，来说下@Async的简单使用
@Async在SpringBoot中的使用较为简单，所在位置如下：
一.启动类加入注解@EnableAsync
第一步就是在启动类中加入@EnableAsync注解 启动类代码如下：
@SpringBootApplication
@EnableAsync//可以写在具体配置类上
public class EurekaApplication {
public static void main(String[] args) {
SpringApplication.run(EurekaApplication.class, args);
}
}
二.编写MyAsyncConfigurer类
MyAsyncConfigurer类实现了AsyncConfigurer接口，重写AsyncConfigurer接口的两个重要方法：
1.getAsyncExecutor：自定义线程池，若不重写会使用默认的线程池。
2.getAsyncUncaughtExceptionHandler:捕捉IllegalArgumentException异常.
一方法很好理解。二方法中提到的IllegalArgumentException异常在之后会说明。代码如下：
/**
* @author hsw
* @Date 20:12 2018/8/23
*/
@Slf4j
@Component
public class MyAsyncConfigurer implements AsyncConfigurer {
@Override
public Executor getAsyncExecutor() {
//定义一个最大为10个线程数量的线程池
ExecutorService service = Executors.newFixedThreadPool(10);
return service;
}
@Override
public AsyncUncaughtExceptionHandler getAsyncUncaughtExceptionHandler() {
return new MyAsyncExceptionHandler();
}
class MyAsyncExceptionHandler implements AsyncUncaughtExceptionHandler {
@Override
public void handleUncaughtException(Throwable throwable, Method method, Object... objects) {
log.info("Exception message - " + throwable.getMessage());
log.info("Method name - " + method.getName());
for (Object param : objects) {
log.info("Parameter value - " + param);
}
}
}
}
三.三种测试方法
1.无参无返回值方法
2.有参无返回值方法
3.有参有返回值方法
具体代码如下：
/**
* @author hsw
* @Date 20:07 2018/8/23
*/
@Slf4j
@Component
public class AsyncExceptionDemo {
@Async
public void simple() {
log.info("this is a void method");
}
@Async
public void inputDemo (String s) {
log.info("this is a input method,{}",s);
throw new IllegalArgumentException("inputError");
}
@Async
public Future hardDemo (String s) {
log.info("this is a hard method,{}",s);
Future future;
try {
Thread.sleep(3000);
throw new IllegalArgumentException();
}catch (InterruptedException e){
future = new AsyncResult("InterruptedException error");
}catch (IllegalArgumentException e){
future = new AsyncResult("i am throw IllegalArgumentException error");
}
return future;
}
}
在第二种方法中，抛出了一种名为IllegalArgumentException的异常，在上述第二步中，我们已经通过重写getAsyncUncaughtExceptionHandler方法，完成了对产生该异常时的处理。在处理方法中我们简单列出了异常的各个信息。ok，现在该做的准备工作都已完成，加个测试方法看看结果如何
/**
* @author hsw
* @Date 20:16 2018/8/23
*/
@RunWith(SpringRunner.class)
@SpringBootTest
@Slf4j
public class AsyncExceptionDemoTest {
@Autowired
private AsyncExceptionDemo asyncExceptionDemo;
@Test
public void simple() {
for (int i=0;i<3;i++){
try {
asyncExceptionDemo.simple();
asyncExceptionDemo.inputDemo("input");
Future future = asyncExceptionDemo.hardDemo("hard");
log.info(future.get());
} catch (InterruptedException e) {
e.printStackTrace();
} catch (ExecutionException e) {
e.printStackTrace();
}
}
}
}
测试结果如下：
2018-08-25 16:25:03.856 INFO 4396 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : Started AsyncExceptionDemoTest in 3.315 seconds (JVM running for 4.184)
2018-08-25 16:25:03.947 INFO 4396 --- [pool-1-thread-1] com.hsw.test.async.AsyncExceptionDemo : this is a void method
2018-08-25 16:25:03.947 INFO 4396 --- [pool-1-thread-3] com.hsw.test.async.AsyncExceptionDemo : this is a hard method,hard
2018-08-25 16:25:03.947 INFO 4396 --- [pool-1-thread-2] com.hsw.test.async.AsyncExceptionDemo : this is a input method,input
2018-08-25 16:25:03.947 INFO 4396 --- [pool-1-thread-2] com.hsw.test.async.MyAsyncConfigurer : Exception message - inputError
2018-08-25 16:25:03.947 INFO 4396 --- [pool-1-thread-2] com.hsw.test.async.MyAsyncConfigurer : Method name - inputDemo
2018-08-25 16:25:03.947 INFO 4396 --- [pool-1-thread-2] com.hsw.test.async.MyAsyncConfigurer : Parameter value - input
2018-08-25 16:25:06.947 INFO 4396 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : i am throw IllegalArgumentException error
2018-08-25 16:25:06.948 INFO 4396 --- [pool-1-thread-4] com.hsw.test.async.AsyncExceptionDemo : this is a void method
2018-08-25 16:25:06.948 INFO 4396 --- [pool-1-thread-6] com.hsw.test.async.AsyncExceptionDemo : this is a hard method,hard
2018-08-25 16:25:06.948 INFO 4396 --- [pool-1-thread-5] com.hsw.test.async.AsyncExceptionDemo : this is a input method,input
2018-08-25 16:25:06.948 INFO 4396 --- [pool-1-thread-5] com.hsw.test.async.MyAsyncConfigurer : Exception message - inputError
2018-08-25 16:25:06.948 INFO 4396 --- [pool-1-thread-5] com.hsw.test.async.MyAsyncConfigurer : Method name - inputDemo
2018-08-25 16:25:06.948 INFO 4396 --- [pool-1-thread-5] com.hsw.test.async.MyAsyncConfigurer : Parameter value - input
2018-08-25 16:25:09.949 INFO 4396 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : i am throw IllegalArgumentException error
2018-08-25 16:25:09.950 INFO 4396 --- [pool-1-thread-7] com.hsw.test.async.AsyncExceptionDemo : this is a void method
2018-08-25 16:25:09.950 INFO 4396 --- [pool-1-thread-8] com.hsw.test.async.AsyncExceptionDemo : this is a input method,input
2018-08-25 16:25:09.950 INFO 4396 --- [pool-1-thread-8] com.hsw.test.async.MyAsyncConfigurer : Exception message - inputError
2018-08-25 16:25:09.950 INFO 4396 --- [pool-1-thread-9] com.hsw.test.async.AsyncExceptionDemo : this is a hard method,hard
2018-08-25 16:25:09.950 INFO 4396 --- [pool-1-thread-8] com.hsw.test.async.MyAsyncConfigurer : Method name - inputDemo
2018-08-25 16:25:09.950 INFO 4396 --- [pool-1-thread-8] com.hsw.test.async.MyAsyncConfigurer : Parameter value - input
2018-08-25 16:25:12.950 INFO 4396 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : i am throw IllegalArgumentException error
2018-08-25 16:25:12.953 INFO 4396 --- [ Thread-2] o.s.w.c.s.GenericWebApplicationContext : Closing org.springframework.web.context.support.GenericWebApplicationContext@71075444: startup date [Sat Aug 25 16:25:01 CST 2018]; root of context hierarchy
测试成功。
到此为止，关于@Async注解的基本使用内容结束。但是在测试过程中，我注意到线程名的命名为默认的pool-1-thread-X，虽然可以分辨出不同的线程在进行作业，但依然很不方便，为什么默认会以这个命名方式进行命名呢？
线程池的命名
点进Executors.newFixedThreadPool，发现在初始化线程池的时候有另一种方法
public static ExecutorService newFixedThreadPool(int nThreads, ThreadFactory threadFactory)
那么这个ThreadFactory为何方神圣？继续ctrl往里点，在类中发现这么一个实现类。
破案了破案了。原来是在这里对线程池进行了命名。那我们只需自己实现ThreadFactory接口，对命名方法进行重写即可，完成代码如下：
static class MyNamedThreadFactory implements ThreadFactory {
private static final AtomicInteger poolNumber = new AtomicInteger(1);
private final ThreadGroup group;
private final AtomicInteger threadNumber = new AtomicInteger(1);
private final String namePrefix;
MyNamedThreadFactory(String name) {
SecurityManager s = System.getSecurityManager();
group = (s != null) ? s.getThreadGroup() : Thread.currentThread().getThreadGroup();
if (null == name || name.isEmpty()) {
name = "pool";
}
namePrefix = name + "-" + poolNumber.getAndIncrement() + "-thread-";
}
public Thread newThread(Runnable r) {
Thread t = new Thread(group, r, namePrefix + threadNumber.getAndIncrement(), 0);
if (t.isDaemon())
t.setDaemon(false);
if (t.getPriority() != Thread.NORM_PRIORITY)
t.setPriority(Thread.NORM_PRIORITY);
return t;
}
}
然后在创建线程池的时候加上新写的类即可对线程名进行自定义。
@Override
public Executor getAsyncExecutor() {
ExecutorService service = Executors.newFixedThreadPool(10,new MyNamedThreadFactory("HSW"));
return service;
}
看看重命名后的执行结果。
2018-08-25 16:42:44.068 INFO 46028 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : Started AsyncExceptionDemoTest in 3.038 seconds (JVM running for 3.83)
2018-08-25 16:42:44.155 INFO 46028 --- [ HSW-1-thread-3] com.hsw.test.async.AsyncExceptionDemo : this is a hard method,hard
2018-08-25 16:42:44.155 INFO 46028 --- [ HSW-1-thread-2] com.hsw.test.async.AsyncExceptionDemo : this is a input method,input
2018-08-25 16:42:44.155 INFO 46028 --- [ HSW-1-thread-1] com.hsw.test.async.AsyncExceptionDemo : this is a void method
2018-08-25 16:42:44.155 INFO 46028 --- [ HSW-1-thread-2] com.hsw.test.async.MyAsyncConfigurer : Exception message - inputError
2018-08-25 16:42:44.155 INFO 46028 --- [ HSW-1-thread-2] com.hsw.test.async.MyAsyncConfigurer : Method name - inputDemo
2018-08-25 16:42:44.155 INFO 46028 --- [ HSW-1-thread-2] com.hsw.test.async.MyAsyncConfigurer : Parameter value - input
2018-08-25 16:42:47.155 INFO 46028 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : i am throw IllegalArgumentException error
2018-08-25 16:42:47.156 INFO 46028 --- [ HSW-1-thread-4] com.hsw.test.async.AsyncExceptionDemo : this is a void method
2018-08-25 16:42:47.156 INFO 46028 --- [ HSW-1-thread-5] com.hsw.test.async.AsyncExceptionDemo : this is a input method,input
2018-08-25 16:42:47.156 INFO 46028 --- [ HSW-1-thread-6] com.hsw.test.async.AsyncExceptionDemo : this is a hard method,hard
2018-08-25 16:42:47.156 INFO 46028 --- [ HSW-1-thread-5] com.hsw.test.async.MyAsyncConfigurer : Exception message - inputError
2018-08-25 16:42:47.156 INFO 46028 --- [ HSW-1-thread-5] com.hsw.test.async.MyAsyncConfigurer : Method name - inputDemo
2018-08-25 16:42:47.156 INFO 46028 --- [ HSW-1-thread-5] com.hsw.test.async.MyAsyncConfigurer : Parameter value - input
2018-08-25 16:42:50.156 INFO 46028 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : i am throw IllegalArgumentException error
2018-08-25 16:42:50.157 INFO 46028 --- [ HSW-1-thread-7] com.hsw.test.async.AsyncExceptionDemo : this is a void method
2018-08-25 16:42:50.157 INFO 46028 --- [ HSW-1-thread-8] com.hsw.test.async.AsyncExceptionDemo : this is a input method,input
2018-08-25 16:42:50.157 INFO 46028 --- [ HSW-1-thread-9] com.hsw.test.async.AsyncExceptionDemo : this is a hard method,hard
2018-08-25 16:42:50.157 INFO 46028 --- [ HSW-1-thread-8] com.hsw.test.async.MyAsyncConfigurer : Exception message - inputError
2018-08-25 16:42:50.157 INFO 46028 --- [ HSW-1-thread-8] com.hsw.test.async.MyAsyncConfigurer : Method name - inputDemo
2018-08-25 16:42:50.157 INFO 46028 --- [ HSW-1-thread-8] com.hsw.test.async.MyAsyncConfigurer : Parameter value - input
2018-08-25 16:42:53.157 INFO 46028 --- [ main] c.hsw.test.async.AsyncExceptionDemoTest : i am throw IllegalArgumentException error
2018-08-25 16:42:53.161 INFO 46028 --- [ Thread-2] o.s.w.c.s.GenericWebApplicationContext : Closing org.springframework.web.context.support.GenericWebApplicationContext@71075444: startup date [Sat Aug 25 16:42:41 CST 2018]; root of context hierarchy
NICE!