Spring常用配置——SpringEvent

Spring的事件（Application Event）为Bean之间的消息通信提供了支持。当一个Bean处理完一个任务之后，希望另一个Bean知道并能做相应的处理，这是我们就需要让另外一个Bean监听当前Bean所发送的事件

Spring的事件需要遵循如下流程：

（1）自定义事件，继承ApplicationEvent

（2）定义事件监听器，实现ApplicationListener

（3）使用容器发布事件。

示例代码：

DemoEvent.java

package com.minivison.caixing.learn.event;

import org.springframework.context.ApplicationEvent;

/**
 *  

 *
 * @author caixing

 * @version 1.0

 * @taskId 

 * @CreateDate 2018年04月17日 

 */
public class DemoEvent extends ApplicationEvent {

    private static final long serialVersionUID = -2419537024459602985L;
    private String msg;

    public DemoEvent(Object source,String msg) {
        super(source);
        this.msg=msg;
    }

    public String getMsg() {
        return msg;
    }

    public void setMsg(String msg) {
        this.msg = msg;
    }
}

DemoListener.java

package com.minivison.caixing.learn.event;

import jdk.internal.org.objectweb.asm.tree.TryCatchBlockNode;
import org.springframework.context.ApplicationListener;
import org.springframework.stereotype.Component;

/**
 *  

 *
 * @author caixing

 * @version 1.0

 * @taskId 

 * @CreateDate 2018年04月17日 

 */
@Component
public class DemoListener implements ApplicationListener {

    @Override
    public void onApplicationEvent(DemoEvent demoEvent) {
        String msg = demoEvent.getMsg();
        try {
            System.out.println("我接收到消息：" + msg);
            /*
            for(;;){

            }
*/
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
}

DemoService.java

package com.minivison.caixing.learn.event;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.ApplicationContext;
import org.springframework.stereotype.Service;

/**
 *  

 *
 * @author caixing

 * @version 1.0

 * @taskId 

 * @CreateDate 2018年04月17日 

 */
@Service
public class DemoService {

    @Autowired
    private ApplicationContext context;

    public void msg(String msg){
        context.publishEvent(new DemoEvent(this,msg));
        System.out.println(msg);
    }


}

EventConfig.java

package com.minivison.caixing.learn.event;

import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

/**
 *  

 *
 * @author caixing

 * @version 1.0

 * @taskId 

 * @CreateDate 2018年04月17日 

 */
@Configuration
@ComponentScan("com.minivison.caixing.learn.event")
public class EventConfig {
}

Main.java

package com.minivison.caixing.learn;

import com.minivison.caixing.learn.beaninit.BeanConfig;
import com.minivison.caixing.learn.beaninit.BeanWayService;
import com.minivison.caixing.learn.beaninit.JSR250WayService;
import com.minivison.caixing.learn.common.ElConfig;
import com.minivison.caixing.learn.event.DemoService;
import com.minivison.caixing.learn.event.EventConfig;
import org.springframework.context.ApplicationContext;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
import org.springframework.util.Base64Utils;

import javax.imageio.stream.FileImageInputStream;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;

/**
 *  

 *
 * @author caixing

 * @version 1.0

 * @taskId 

 * @CreateDate 2018年04月12日 

 */
public class Main {
    public static void main(String[] args) throws Exception {
        AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(EventConfig.class);
        DemoService service = context.getBean(DemoService.class);
        service.msg("hello event");
        context.close();
        //String str = Base64Utils.encodeToString(image2byte("E:\\123.jpg"));
        //System.out.println(str);

    }

    public static byte[] image2byte(String path) {
        byte[] data = null;
        FileImageInputStream input = null;
        try {
            input = new FileImageInputStream(new File(path));
            ByteArrayOutputStream output = new ByteArrayOutputStream();
            byte[] buf = new byte[1024];
            int numBytesRead = 0;
            while ((numBytesRead = input.read(buf)) != -1) {
                output.write(buf, 0, numBytesRead);
            }
            data = output.toByteArray();
            output.close();
            input.close();
        } catch (FileNotFoundException ex1) {
            ex1.printStackTrace();
        } catch (IOException ex1) {
            ex1.printStackTrace();
        }
        return data;
    }
}