服务器运行的状态，修改Spring中的applicationContext.xml配置文件

最近在做一个项目，需要访问多个数据库，而且需要在服务器运行不重新启动的情况下，动态的修改spring中配置的数据源datasource，在网上找了很多资料，最后找到了适合我的方法，下面总结一下。 
spring的配置文件是在容器启动的时候就加载到内存中的，如果手动改了application.xml，我们必须要重新启动服务器配置文件才会生效。而在spring中提供了一个类WebApplicationContext，这个类可以让你获得一些bean，可以修改内存中的信息，我就是通过这个类来实现的。下面是我具体的代码。 

package com.southdigital.hospital; 

import java.io.IOException; 

import javax.servlet.ServletContext; 
import javax.servlet.ServletException; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

import org.springframework.web.context.WebApplicationContext; 
import org.springframework.web.context.support.WebApplicationContextUtils; 

import com.mchange.v2.c3p0.ComboPooledDataSource; 

public class ChangeSpringConfig extends HttpServlet 
{ 

private String ipAddress = "127.0.0.1"; 

/** 
* The doGet method of the servlet. <br> 
* 
* This method is called when a form has its tag value method equals to get. 
* 
* @param request the request send by the client to the server 
* @param response the response send by the server to the client 
* @throws ServletException if an error occurred 
* @throws IOException if an error occurred 
*/ 


public void doGet(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException 
{ 
doPost(request, response); 
} 

/** 
* The doPost method of the servlet. <br> 
* 
* This method is called when a form has its tag value method equals to post. 
* 
* @param request the request send by the client to the server 
* @param response the response send by the server to the client 
* @throws ServletException if an error occurred 
* @throws IOException if an error occurred 
*/ 
public void doPost(HttpServletRequest request, HttpServletResponse response) 
throws ServletException, IOException 
{ 
//先取得servleContext对象，提供给spring的WebApplicationUtils来动态修改applicationContext.xml 

ipAddress = request.getParameter("ipAddress"); 
System.out.println(ipAddress); 

ServletContext servletContext = this.getServletContext(); 
WebApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(servletContext); 
    ComboPooledDataSource cpds = (ComboPooledDataSource) applicationContext.getBean("dataSource"); 
    cpds.setJdbcUrl("jdbc:mysql://"+ipAddress+":3306/ssh"); 

} 

} 

注意：通过这种方法修改applicationContext.xml文件的时候用c3p0,而不可以用dbcp，dbcp不支持动态修改读取到内存里面的数据。

对于proxool 的datasource 类是 org.logicalcobwebs.proxool.ProxoolDataSource