（一）Spring容器相关操作
一、spring事件
spring的事件有如下两个成员。
1、ApplicationEvent，容器事件，由容器发布
2、ApplicationListener 监听器，可以由容器中的任何监听器Bean担任
（1）先顶一个spring的容器事件：
package cn.study.basic;
import org.springframework.context.ApplicationEvent;
public class EmailEvent extends ApplicationEvent {
private String address;
private String text;
public EmailEvent(Object source) {
super(source);
}
public EmailEvent(Object source, String address, String text) {
super(source);
this.address = address;
this.text = text;
}
public String getAddress() {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public String getText() {
return text;
}
public void setText(String text) {
this.text = text;
}
}
（2）编写容器监听器代码：
package cn.study.basic;
import org.springframework.context.ApplicationListener;
public class EmailListener implements ApplicationListener<EmailEvent> {
@Override
public void onApplicationEvent(EmailEvent arg0) {
System.out.println(arg0 instanceof EmailEvent);
if (arg0 instanceof EmailEvent) {
EmailEvent ee = (EmailEvent) arg0;
System.out.println("address:" + ee.getAddress());
} else {
System.out.println("container:" + arg0);
}
}
}
（3）、bean.xml文件中加入如下配置：
<bean class="cn.study.basic.EmailListener"></bean>
（4）、测试方法
package cn.study.basic.test;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import cn.study.basic.EmailEvent;
public class TestAMain {
@Test
public void testApp() throws Exception {
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
EmailEvent emailEvent = new EmailEvent("object", "address", "test");
context.publishEvent(emailEvent);
}
}
运行代码，执行结果如下所示：
true
address:address
二、bean获取spring容器
在web开发的过程中，spring容器通常使用声明式方法配置产生，开发者只需要在web.xml中配置相应的Listener，在启动的时候就会初始化Spring容器，但是某些比较特殊的时候，容器中的Bean需要主动访问Spring容器，有如下两种方式。
（1）、实现BeanFactoryAware接口，在实现接口的同时，必须实现如下方法。
public void setBeanFactory(BeanFactory arg0) throws BeansException {
}
（2）、实现ApplicationContextAware接口，同时需要实现如下方法
@Override
public void setApplicationContext(ApplicationContext arg0) throws BeansException {
}
下面使用第二种方法来实现以下小示例，首先实现接口，代码如下：
package cn.study.basic;
import org.springframework.beans.BeansException;
import org.springframework.context.ApplicationContext;
import org.springframework.context.ApplicationContextAware;
public class GetApContext implements ApplicationContextAware {
private ApplicationContext ctx;
@Override
public void setApplicationContext(ApplicationContext arg0) throws BeansException {
this.ctx = arg0;
}
public ApplicationContext getContext() {
return ctx;
}
}
还需要在bean.xml文件中配置bean，如下
<bean class="cn.study.basic.GetApContext"></bean>
测试方法如下：
package cn.study.basic.test;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import cn.study.basic.GetApContext;
public class TestContext {
@Test
public void testContext() throws Exception {
ApplicationContext context = new ClassPathXmlApplicationContext("bean.xml");
GetApContext ctx = (GetApContext) context.getBean("spContext");
System.out.println(ctx.getContext());
System.out.println(context==ctx.getContext());
}
}
测试结果如下所示：
--->org.springframework.context.support.ClassPathXmlApplicationContext@2c11b4c2: startup date [Fri Oct 03 14:04:27 CST 2014]; root of context hierarchy
true
三、几种后处理器
1、bean后处理器BeanPostProcessor，需要实现bean后处理，需要实现接口：BeanPostProcessor ，代码如下
（1）、实现接口BeanPostProcessor
package cn.study.basic.test6;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;
public class MyBeanPostProcessor implements BeanPostProcessor {
@Override
public Object postProcessAfterInitialization(Object bean, String beanName) throws BeansException {
System.out.println("Bean后处理器在初始化之前对【" + beanName + "】进行了增强处理");
return bean;
}
@Override
public Object postProcessBeforeInitialization(Object bean, String beanName) throws BeansException {
System.out.println("Bean后处理器在初始化之前对【" + beanName + "】进行了增强处理");
if (bean instanceof Chinese) {
Chinese chinese = (Chinese) bean;
chinese.useAxe();
}
return bean;
}
}
（2）、bean.xml配置文件中：
<bean id="myBeanPostProcessor" class="cn.study.basic.test6.MyBeanPostProcessor"></bean>
（3）、测试方法
package cn.study.basic.test6;
import org.junit.Test;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.core.io.ClassPathResource;
import cn.study.basic.ContextUtils;
import cn.study.basic.test4.Person;
public class TestMain {
@Test
public void testBeanFactory() throws Exception {
ApplicationContext ctx=ContextUtils.getContext();
ctx.getBean("dd");
}
}
2、容器后处理BeanFactoryPostProcessor
（1）、接口BeanFactoryPostProcessor
package cn.study.basic.test6;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanFactoryPostProcessor;
import org.springframework.beans.factory.config.ConfigurableListableBeanFactory;
public class MyFactoryBeanFactoryProcessor implements BeanFactoryPostProcessor {
@Override
public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException {
System.out.println("the container of spring :" + beanFactory);
}
}
（2）测试方法
package cn.study.basic.test6;
import org.junit.Test;
import org.springframework.beans.factory.xml.XmlBeanFactory;
import org.springframework.context.ApplicationContext;
import org.springframework.core.io.ClassPathResource;
import cn.study.basic.ContextUtils;
import cn.study.basic.test4.Person;
public class TestMain {
@Test
public void testMain() throws Exception {
ClassPathResource isr = new ClassPathResource("bean.xml");
XmlBeanFactory factory = new XmlBeanFactory(isr);
MyBeanPostProcessor prr = (MyBeanPostProcessor) factory.getBean("myBeanPostProcessor");
factory.addBeanPostProcessor(prr);
Person person = factory.getBean("dd", Person.class);
person.getName();
}
}
3、属性占位符配置器PropertyPlaceholderConfigurer，是一个容器后处理器，负责读取properties文件中的内容，并将这些数据设置为Spring配置文件的元数据
<!-- PropertyPlaceholderConfigurer是一个Bean后处理器，它会读取
属性文件信息，并将这些信息设置成Spring配置文件的元数据。 -->
<bean class=
"org.springframework.beans.factory.config.PropertyPlaceholderConfigurer">
<property name="locations">
<list>
<value>dbconn.properties</value>
</list>
</property>
</bean>
<!-- 定义数据源Bean，使用C3P0数据源实现 -->
<bean id="dataSource" class="com.mchange.v2.c3p0.ComboPooledDataSource"
destroy-method="close">
<!-- 指定连接数据库的驱动 -->
<property name="driverClass" value="${jdbc.driverClassName}"/>
<!-- 指定连接数据库的URL -->
<property name="jdbcUrl" value="${jdbc.url}"/>
<!-- 指定连接数据库的用户名 -->
<property name="user" value="${jdbc.username}"/>
<!-- 指定连接数据库的密码 -->
<property name="password" value="${jdbc.password}"/>
</bean>
