web项目中servlet利用servletContext对象读取资源文件

package test;import java.io.FileInputStream;import java.io.FileNotFoundException;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;/** * servlet中庸servletContext读取资源文件 */public class ServletDemo11 extends HttpServlet {public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {/*// 资源文件在src下，那么在web服务器中的位置是WEB-INF/classes下// /代表web程序的根目录InputStream in = this.getServletContext().getResourceAsStream("/WEB-INF/classes/db.properties");//资源在包中，那么在web服务器中的位置是WEB-INF/classes/package下InputStream in = this.getServletContext().getResourceAsStream("/WEB-INF/classes/test/db.properties");//资源在WebRoot下，那么在web服务器中的位置是web程序的根目录下InputStream in = this.getServletContext().getResourceAsStream("/db.properties");read(in);*///chuanTong();chuanTong2();}/** * 传统的SE读取资源文件方式是错误的： */public void chuanTong() {//在src下try {//这样是读取不出来的，因为相对路径是相对于虚拟机加载的路径，也就是tomcat启动时的bin目录//所以在web程序中读取资源时要用servletContext对象FileInputStream fin = new FileInputStream("WEB-INF/classes/db.properties");read(fin);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} }/** * 传统的SE读取资源文件方式是错误的： * 但是如果先用servletContext对象拿到资源的绝对路径是可以的 * 而且这种方法还有个好处就是可以得到文件的名称，getResourceAsStream是不能获取资源名称的 * 比如做下载时，就需要拿到资源名称 */public void chuanTong2() {//在src下try {String path = this.getServletContext().getRealPath("WEB-INF/classes/db.properties");String name = path.substring(path.lastIndexOf("\\")+1);System.out.println("文件名称" + name);FileInputStream fin = new FileInputStream(path);read(fin);} catch (FileNotFoundException e) {e.printStackTrace();} catch (IOException e) {e.printStackTrace();} }/** *  * @param in * @throws IOException * 抽取出来的代码 */private void read(InputStream in) throws IOException {Properties prop = new Properties();prop.load(in);String url = prop.getProperty("url");String username = prop.getProperty("username");String password = prop.getProperty("password");System.out.println(url);System.out.println(username);System.out.println(password);}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doGet(request, response);}}