spring_07使用spring的特殊bean、完成分散配置

一.   前言

　　  分散配置思路:创建properties文件,添加数据,在beans文件中先配置properties文件,再在bean中使用占位符引用数据

1. 对于bean的生命周期中的很多处理接口,处理方法都是spring自带bean完成,即spring的特殊bean.

　　  2. 当通过 context:property-placeholder 引入 属性文件的时候，有多个需要使用 , 号间隔.

　　  3.beans文件使用占位符引用properties文件中内容:eg.${key}

二. 分散配置　

　　通过自建properties文件,配置键值,在spring配置文件中读取,实现分散配置

　　db.properties文件　　

　　username=admin
　　password=123456
　　driver=com.ahd.www

　　配置文件beans:

<?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 -->
    <!-- 方式一:配置bean 
    <bean class="PropertyPlaceholderConfigurer">
        <property name="locations">
            <list>
                <value>com/ahd/dispatcher/db.properties</value>
            </list>
        </property>
    </bean>        
    -->    
<!-- 方式二: -->
    <context:property-placeholder location="classpath:com/ahd/dispatcher/db.properties"></context:property-placeholder>
                
    <bean id="dbutil" class="com.ahd.dispatcher.DBUtil">
        <property name="username"><value>${username}</value></property>
        <property name="password"><value>${password}</value></property>
        <property name="drivername"><value>${driver}</value></property>
    </bean>

</beans>

　　

　　DBUtil类:　　

package com.ahd.dispatcher;

public class DBUtil {
    
    private String username;
    private String password;
    private String drivername;
    
    
    public DBUtil() {
    }
    public String getUsername() {
        return username;
    }
    public void setUsername(String username) {
        this.username = username;
    }
    public String getPassword() {
        return password;
    }
    public void setPassword(String password) {
        this.password = password;
    }
    public String getDrivername() {
        return drivername;
    }
    public void setDrivername(String drivername) {
        this.drivername = drivername;
    }
    
    
}

　　测试类:Test.java

package com.ahd.dispatcher;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {

    public static void main(String[] args) {
        // TODO Auto-generated method stub
        ApplicationContext ac=new ClassPathXmlApplicationContext("com/ahd/dispatcher/beans.xml");
        
        DBUtil dbutil = (DBUtil) ac.getBean("dbutil");
        
        System.out.println(dbutil.getUsername()+"    "+dbutil.getPassword());
    }

}