07如何读取web应用下的资源文件

package gz.itcast.b_resource;

 

import java.io.IOException;

import java.io.InputStream;

import java.util.Properties;

 

import javax.servlet.ServletException;

import javax.servlet.http.HttpServlet;

import javax.servlet.http.HttpServletRequest;

import javax.servlet.http.HttpServletResponse;

/**

 * 读取web应用下的资源文件（例如properties）

 * @author APPle

 */

public class ResourceDemo extends HttpServlet {

 

         public void doGet(HttpServletRequest request, HttpServletResponse response)

                            throws ServletException, IOException {

                   /**

                    *  . 代表java命令运行目录。java运行命令在哪里？？ 在tomcat/bin目录下

                    *   结论： 在web项目中， . 代表在tomcat/bin目录下开始，所以不能使用这种相对路径。

                    */

                  

                  

                   //读取文件。在web项目下不要这样读取。因为.表示在tomcat/bin目录下

                   /*File file = new File("./src/db.properties");

                   FileInputStream in = new FileInputStream(file);*/

                  

                   /**

                    * 使用web应用下加载资源文件的方法

                    */

                   /**

                    * 1. getRealPath读取,返回资源文件的绝对路径

                    */

                   /*String path = this.getServletContext().getRealPath("/WEB-INF/classes/db.properties");

                   System.out.println(path);

                   File file = new File(path);

                   FileInputStream in = new FileInputStream(file);*/

                  

                   /**

                    * 2. getResourceAsStream() 得到资源文件，返回的是输入流（推荐）

                    */

                   InputStream in = this.getServletContext().getResourceAsStream("/WEB-INF/classes/db.properties");

                  

                  

                   Properties prop = new Properties();

                   //读取资源文件

                   prop.load(in);

                  

                   String user = prop.getProperty("user");

                   String password = prop.getProperty("password");

                   System.out.println("user="+user);

                   System.out.println("password="+password);

                  

         }

 

}