为什么80%的码农都做不了架构师？>>> 
为什么要用EventBus？
实现了进程内广播与监听，代码层实现了逻辑解耦。通常用于发短信、邮件、写日志、数据埋点等场景。
为什么要整合spring重新造轮子？
原因是直接使用EventBus监听的类是不被spring托管，也就是说 @Subscribe类是不能直接通过spring 注入bean。
代码实现：
欢迎访问 : https://github.com/awoter/fact-bus
/***
** 用于标记Event事件
**/
public interface BaseEvent {
}/***
** 所有Event处理类都要继承此Adapter类 实现process进行相关event处理
**/
public abstract class EventAdapter {
private static final Logger logger = LoggerFactory.getLogger(EventAdapter.class);
private static final String METHOD_NAME = "process";
@Subscribe
@SuppressWarnings("all")
public void onEvent(BaseEvent event) {
if (ReflectionUtils.findMethod(this.getClass(), METHOD_NAME, event.getClass()) != null) {
try {
if (!process((E)event)) {
logger.warn("handle event {} fail", event.getClass());
}
} catch (Exception e) {
logger.error(String.format("handle event %s exception", event.getClass()), e);
}
}
}
public abstract boolean process(E e);
} /***
** EventBus处理类，主要用于注册或注销及发布相关事件
*/
public class EventBusFacade {
private static final Logger logger = LoggerFactory.getLogger(EventBusFacade.class);
private final static EventBus eventBus = new EventBus();
public static void post(BaseEvent event) {
execute(event);
}
public static void execute(BaseEvent event) {
if(event == null){
return ;
}
eventBus.post(event);
}
public static void register(EventAdapter handler) {
if(handler == null){
return ;
}
eventBus.register(handler);
logger.info("Registered eventAdapter class: {}", handler.getClass());
}
public static void unregister(EventAdapter handler) {
if(handler == null){
return ;
}
eventBus.unregister(handler);
logger.info("Unregisted eventAdapter class: {}", handler.getClass());
}
}三个类就完成核心的封装，下面通过什么办法可以实现自动注册及注销EventAdapter呢，请继续往下看：
@Configuration
@SuppressWarnings("all")
public class EventBusConfiguration implements InitializingBean, DisposableBean {
@Autowired
private ApplicationContext applicationContext;
private Map beans = null;
@Override
public void afterPropertiesSet() throws Exception {
beans = applicationContext.getBeansOfType(EventAdapter.class);
if (beans != null) {
for (EventAdapter eventAbstract : beans.values()) {
EventBusFacade.register(eventAbstract);
}
}
}
@Override
public void destroy() throws Exception {
if (beans != null) {
for (EventAdapter eventAbstract : beans.values()) {
EventBusFacade.unregister(eventAbstract);
}
}
}
} OK，到这就已实现自动注册及注销 EventAdapter ，再加上下面这个激活注解就完美了。
@Configuration
@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Import(EventBusConfiguration.class)
@Documented
public @interface EnableEventBus {
}到此，封装结束；
使用示例：
public class TestEvent implements BaseEvent{
private String name;
public TestEvent(){}
public TestEvent(String a){
this.name = a;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}
@Component
public class TestEventHandler extends EventAdapter{
private static final Logger logger = LoggerFactory.getLogger(EventBusFacade.class);
@Override
public boolean process(TestEvent e) {
logger.info("==================== 收到测试事件 ===================");
return true;
}
}
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration("classpath:/spring.xml")
public class TestLaunch {
@Test
public void testExecute() {
EventBusFacade.execute(new TestEvent()); //发布事件
}
}