spring教程笔记5

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本文介绍Spring框架中使用特殊Bean如BeanPostProcessor进行生命周期控制，以及如何通过properties文件进行DBUtil对象的属性注入，实现数据库连接配置的灵活管理。

使用Spring的特殊bean

package com.hsp.beanlife;

import org.springframework.beans.BeansException;
import org.springframework.beans.factory.config.BeanPostProcessor;

public class MyBeanPostProcessor implements BeanPostProcessor {

	public Object postProcessAfterInitialization(Object arg0, 

String arg1)
			throws BeansException {
		// TODO Auto-generated method stub
		System.out.println("postProcessAfterInitialization 函

数被调用");
		System.out.println(arg0+" 被创建的时间是"+new 

java.util.Date());
		return arg0;
	}

	public Object postProcessBeforeInitialization(Object arg0, 

String arg1)
			throws BeansException {
		// TODO Auto-generated method stub
		System.out.println("postProcessBeforeInitialization 

函数被调用");
		return arg0;
	}

}

<!-- 配置我们的自己后置处理器(有点类似我们的filter) -->
<bean id="myBeanPostProcessor" 

class="com.hsp.beanlife.MyBeanPostProcessor" />
</beans>

通过properties文件注入特殊bean

package com.hsp.dispatch;

public class DBUtil {

	private String drivername;
	private String url;
	private String name;
	private String pwd;
	public String getDrivername() {
		return drivername;
	}
	public void setDrivername(String drivername) {
		this.drivername = drivername;
	}
	public String getUrl() {
		return url;
	}
	public void setUrl(String url) {
		this.url = url;
	}
	public String getName() {
		return name;
	}
	public void setName(String name) {
		this.name = name;
	}
	public String getPwd() {
		return pwd;
	}
	public void setPwd(String pwd) {
		this.pwd = pwd;
	}
}

name=scott
drivername=oracle:jdbc:driver:OracleDirver
url=jdbc:oracle:thin:@127.0.0.1:1521:hsp
pwd=tiger

# key=value

db2.name=scott3
db2.drivername=oracle:jdbc:driver:OracleDirver3
db2.url=jdbc:oracle:thin:@127.0.0.1:1521:hsp3
db2.pwd=tiger3

# key=value

<?xml version="1.0" encoding="utf-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
		xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
		

xmlns:context="http://www.springframework.org/schema/context"
		xmlns:tx="http://www.springframework.org/schema/tx"
		

xsi:schemaLocation="http://www.springframework.org/schema/beans 

http://www.springframework.org/schema/beans/spring-beans-2.5.xsd
				

http://www.springframework.org/schema/context 

http://www.springframework.org/schema/context/spring-context-2.5.xsd
				

http://www.springframework.org/schema/tx 

http://www.springframework.org/schema/tx/spring-tx-2.5.xsd">

<!-- 引入我们的db.properties文件 -->
<context:property-placeholder 

location="classpath:com/hsp/dispatch/db.properties,classpath:com/hsp/

dispatch/db2.properties"/>
<!-- 配置一DBUtil对象 $占位符号 -->
<bean id="dbutil" class="com.hsp.dispatch.DBUtil">
<property name="name" value="${name}" />
<property name="drivername" value="${drivername}" />
<property name="url" value="${url}" />
<property name="pwd" value="${pwd}" />
</bean>

<!-- 配置一DBUtil对象 -->
<bean id="dbutil2" class="com.hsp.dispatch.DBUtil">
<property name="name" value="${db2.name}" />
<property name="drivername" value="${db2.drivername}" />
<property name="url" value="${db2.url}" />
<property name="pwd" value="${db2.pwd}" />
</bean>

</beans>

package com.hsp.dispatch;

import org.springframework.context.ApplicationContext;
import 

org.springframework.context.support.ClassPathXmlApplicationContext;

public class App1 {

	/**
	 * @param args
	 */
	public static void main(String[] args) {
		// TODO Auto-generated method stub
		ApplicationContext ac=new 

ClassPathXmlApplicationContext("com/hsp/dispatch/beans.xml");
	
		DBUtil dbUtil=(DBUtil) ac.getBean("dbutil2");
		System.out.println(dbUtil.getDrivername()+" 

"+dbUtil.getName());
	
	}

}

运行结果：

2020-3-2 14:15:34 
org.springframework.context.support.AbstractApplicationContext 

prepareRefresh
信息: Refreshing 

org.springframework.context.support.ClassPathXmlApplicationContext@1e

f9f1d: display name 

[org.springframework.context.support.ClassPathXmlApplicationContext@1

ef9f1d]; startup date [Mon Mar 02 14:15:34 CST 2020]; root of context 

hierarchy
2020-3-2 14:15:34 

org.springframework.beans.factory.xml.XmlBeanDefinitionReader 

loadBeanDefinitions
信息: Loading XML bean definitions from class path resource 

[com/hsp/dispatch/beans.xml]
2020-3-2 14:15:35 

org.springframework.context.support.AbstractApplicationContext 

obtainFreshBeanFactory
信息: Bean factory for application context 

[org.springframework.context.support.ClassPathXmlApplicationContext@1

ef9f1d]: 

org.springframework.beans.factory.support.DefaultListableBeanFactory@

f0c85e
2020-3-2 14:15:35 

org.springframework.core.io.support.PropertiesLoaderSupport 

loadProperties
信息: Loading properties file from class path resource 

[com/hsp/dispatch/db.properties]
2020-3-2 14:15:35 

org.springframework.core.io.support.PropertiesLoaderSupport 

loadProperties
信息: Loading properties file from class path resource 

[com/hsp/dispatch/db2.properties]
2020-3-2 14:15:35 

org.springframework.beans.factory.support.DefaultListableBeanFactory 

preInstantiateSingletons
信息: Pre-instantiating singletons in 

org.springframework.beans.factory.support.DefaultListableBeanFactory@

f0c85e: defining beans 

[org.springframework.beans.factory.config.PropertyPlaceholderConfigur

er#0,dbutil,dbutil2]; root of factory hierarchy
```


oracle:jdbc:driver:OracleDirver3 scott3