Spring's event publishing mechanism

One: Spring's event release

ApplicationContext provides event propagation capabilities for beans, the protagonist of which is the Publishevent () method, which enables you to notify the listener within the system (to implement the Applicationlistener interface).

ApplicationContext this interface, is the spring context, usually get the bean need this interface, this interface is not directly inherit from Beanfactory, the most famous is directly inherit the Applicationpublisher interface, This interface to see the source code can be found: there is only one way, that is the protagonist void Publishevent (Applicationevent event);

Spring provides a aware-based interface with Applicationcontextaware,resourceloaderaware,servletcontextaware (note: STRUTS2 also has this interface, note the distinction), The most common are these three, and spring's event publishing mechanism needs to use the Applicationcontextaware interface.

Implements the Applicationcontextaware bean, which will be injected into the ApplicationContext instance when the bean is initialized (because there is a set (Applictationcontext ctx) method in this interface)

Second: With the above basics, look at the sample code:

1. First create the event class Tradeevent

Package Net.wang.test;import org.springframework.context.applicationevent;/** * Event * @author Liuruowang */public Class Tradeevent extends Applicationevent{public tradeevent (Object source) {super (source); System.out.println ("Event: Tradeevent event!!");}} Event must inherit applicationevent abstract class provided by spring

2. Then write the publisher of the event HelloWorld:

package Net.wang.test;import Org.springframework.context.applicationeventpublisher;import org.springframework.context.applicationeventpublisheraware;/** * Event Publisher * @author Liuruowang */public class HelloWorld Implements Applicationeventpublisheraware{private string Word;public void Setword (string word) {This.word = Word;} Private Applicationeventpublisher tradeeventpublisher;public void Setapplicationeventpublisher ( Applicationeventpublisher applicationeventpublisher) {this.tradeeventpublisher=applicationeventpublisher;} public void Say () {System.out.println ("say:" +this.word); Tradeevent tradeevent = new Tradeevent (New String ("helloworld!")); This.tradeEventPublisher.publishEvent (tradeevent);}} 

Where the event was published in the Say () method

3. The recipient of the last writing event Eventreceiver:

Package Net.wang.test;import org.springframework.context.applicationlistener;/** * Event Recipient * @author Liuruowang */ public class Eventreceiver implements Applicationlistener<tradeevent>{public void Onapplicationevent ( Tradeevent event) {System.out.println ("Listen to Events:" +event.getsource ());}}

The receiver of the event is actually a listener that must implement the Applicationlistener and note that the event tradeevent is written directly into the generic

4.applicationcontext.xml: 

<?xml version= "1.0" encoding= "GBK"? ><beansxmlns= "Http://www.springframework.org/schema/beans" xmlns:xsi= "Http://www.w3.org/2001/XMLSchema-instance" xmlns:p= "http://www.springframework.org/schema/p" xmlns:aop= "http// Www.springframework.org/schema/aop "xmlns:tx=" http://www.springframework.org/schema/tx "xsi:schemalocation=" http ://www.springframework.org/schema/beanshttp://www.springframework.org/schema/beans/spring-beans-3.1.xsdhttp:// WWW.SPRINGFRAMEWORK.ORG/SCHEMA/AOP http://www.springframework.org/schema/aop/spring-aop-3.1.xsdhttp:// Www.springframework.org/schema/tx http://www.springframework.org/schema/tx/spring-tx-3.1.xsd "><bean name=" Hellowrold "class=" Net.wang.test.HelloWorld "><property name=" word "value=" word! " /></bean><bean name= "Eventreceiver" class= "Net.wang.test.EventReceiver"/></beans>

Note that the recipient of the event is written to the configuration file

5. Testing Test:

Package Net.wang.test;import Org.springframework.context.applicationcontext;import Org.springframework.context.support.classpathxmlapplicationcontext;public class Test {public static void main (String [] args) {ApplicationContext ctx=new classpathxmlapplicationcontext ("Applicationcontext.xml"); HelloWorld h = (HelloWorld) ctx.getbean ("Hellowrold"); H.say ();}}

6. The results show:

The results have shown that the heard events indicate success.

Spring's event publishing mechanism