Spring - Spring Data REST - Prevent The Methods in Event Handlers Be Triggered Twice

自定义发布事件机制避免重复触发

最新推荐文章于 2025-09-10 16:19:25 发布

原创最新推荐文章于 2025-09-10 16:19:25 发布 · 851 阅读

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#spring #rest #java

本文介绍如何通过创建自定义注解配置上下文来防止应用事件在不同层次触发多次，具体步骤包括重写发布事件方法、移除默认多播事件调用，并设置自定义上下文到DispatcherServlet。

<span style="background-color: rgb(255, 255, 255);">To prevent the methods be triggered twice, we need to overwrite the </span><strong style="background-color: rgb(255, 255, 255);">publishEvent(ApplicationEvent event)</strong><span style="background-color: rgb(255, 255, 255);"> method, then remove the code below</span>

<span style="white-space:pre">	</span>this.getApplicationEventMulticaster().multicastEvent(event);
        if(this.parent != null) {
            this.parent.publishEvent(event);
        }
So, it need to create a customized AnnotationConfuigWebApplicationContext:
package com.siemens.ct.its.iam.deploy.configuration;

import org.springframework.context.ApplicationEvent;
import org.springframework.context.event.ApplicationEventMulticaster;
import org.springframework.util.Assert;
import org.springframework.web.context.support.AnnotationConfigWebApplicationContext;

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

/**
 * Created by z002x71p on 2015/9/23.
 */
public class MyAnnotationConfigWebApplicationContext extends AnnotationConfigWebApplicationContext {

    public void publishEvent(ApplicationEvent event) {
        Assert.notNull(event, "Event must not be null");
        if(this.logger.isTraceEnabled()) {
            this.logger.trace("Publishing event in " + this.getDisplayName() + ": " + event);
        }

        this.getApplicationEventMulticaster().multicastEvent(event);
    }

    ApplicationEventMulticaster getApplicationEventMulticaster() throws IllegalStateException {
        for(Class<?> clazz = this.getClass() ; clazz != Object.class ; clazz = clazz.getSuperclass()) {
            String className = clazz.getName();
            System.out.println(className);
            if(className.equals("org.springframework.context.support.AbstractApplicationContext")){
                try {
                    Method method = clazz.getDeclaredMethod("getApplicationEventMulticaster") ;
                    method.setAccessible(true);
                    return (ApplicationEventMulticaster) method.invoke(this);
                }catch (NoSuchMethodException | InvocationTargetException | IllegalAccessException e){
                    throw new RuntimeException(e);
                }
            }
        }
        return null;
    }
}
And set it into the DispacherServlet.