Spring事件监听Demo

Spring事件监听实现了观察者模式。本Demo在junit4测试环境中实现

主要有三个类事件类、监听器类、事件发布类（入口）

事件类必须继承 ApplicationEvent，代码如下：

import org.junit.runner.RunWith;
import org.springframework.context.ApplicationEvent;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * Created by *** on 2016/3/15.
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext-indexConfig-test.xml")
public class StudentAddEventTest extends ApplicationEvent {

    private String sname;

    public StudentAddEventTest(Object source, String sname) {
        super(source);
        this.sname = sname;
    }

    public String getSname() {
        return sname;
    }
}

监听器Listener类需实现  ApplicationListener 接口  ApplicationListener可以传入一个泛型的事件类型变量，也可以不传。不传的话，需要在监听到事件发生时（onApplicationEvent）自己判断该事件是不是自己要监听的事件。

import org.junit.runner.RunWith;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * Created by *** on 2016/3/15.
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext-indexConfig-test.xml")
@Component
public class StudentAddListenerTest implements ApplicationListener<StudentAddEventTest> {

    @Override
    public void onApplicationEvent(StudentAddEventTest studentAddEventTest) {
        String sname = studentAddEventTest.getSname();
        System.out.println("增加的学生的名字为：：："+sname);
    }
}

事件发布类实现了 ApplicationContextAware ，实现这个主要是为了拿到 ApplicationContext实例，进而调用他的 publishEvent方法。感觉不实现ApplicationContextAware应该也可以。。。

：

import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
import org.springframework.stereotype.Component;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;

/**
 * Created by *** on 2016/3/15.
 */
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext-indexConfig-test.xml")
@Component
public class StudentAddBeanTest implements ApplicationContextAware {
    private static ApplicationContext applicationContext;

    @Override
    @Autowired
    public void setApplicationContext(ApplicationContext applicationContext) throws BeansException {
        this.applicationContext  = applicationContext;
    }

    public void addStudent(String sname){
        StudentAddEventTest addEvent = new StudentAddEventTest(this, sname);
        applicationContext.publishEvent(addEvent);
    }

    @Test
    public void addTest(){
        StudentAddBeanTest studentBean = new StudentAddBeanTest();
        studentBean.addStudent("张三");
        studentBean.addStudent("李四");
    }

}

需要注意的是 StudentAddListenerTest ——Listener类，StudentAddBeanTest ——事件发布类需在spring容器中注册，Demo中在 applicationContext-indexConfig-test.xml配置了

扫描<context:component-scan> </context:component-scan>路径

然后在类上加了注解@Component，运行测试方法addTest（）经过测试，能顺利实现既定目标。