读取web中不同位置的文件

左手的ㄟ右手 2022-05-16 06:15 179阅读 0赞

package cn.itcast.web.servlet;
    
    import java.io.FileInputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.net.URL;
    import java.util.Properties;
    
    import javax.servlet.ServletContext;
    import javax.servlet.ServletException;
    import javax.servlet.http.HttpServlet;
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    //用servletContext读取web工程不同位置的资源文件
    public class ServletDemo11 extends HttpServlet {
    
        public void doGet(HttpServletRequest request, HttpServletResponse response)
                throws ServletException, IOException {
            test5();
        }
    
        //读取src下面的配置文件
        private void test5() throws IOException {
            InputStream in = this.getServletContext().getResourceAsStream("/WEB-INF/classes/db.properties");
            Properties prop = new Properties();  //map
            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);
        }
    
        //读取src下面的配置文件(传统方式不可取)
        private void test4() throws IOException {
            FileInputStream in = new FileInputStream("classes/db.properties");
            System.out.println(in);
        }
    
    
        //读取配置文件的第三种方式
        private void test3() throws IOException {
            ServletContext context = this.getServletContext();
            URL url = context.getResource("/resource/db.properties");
            InputStream in = url.openStream();
    
        }
    
    
        //读取配置文件的第二种方式
        private void test2() throws IOException {
            ServletContext context = this.getServletContext();
            String realpath = context.getRealPath("/db.properties");  //c:\\sdsfd\sdf\db.properties
    
            //获取到操作文件名   realpath=abc.properties
            String filename = realpath.substring(realpath.lastIndexOf("\\")+1);
            System.out.println("当前读到的文件是：" + filename);
    
    
            FileInputStream in = new FileInputStream(realpath);
            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("文件中有如下数据：");
            System.out.println(url);
            System.out.println(username);
            System.out.println(password);
    
        }
    
    
        //读取配置文件的第一种方式
        private void test1() throws IOException {
    
            ServletContext context = this.getServletContext();
            InputStream in = context.getResourceAsStream("/db.properties");
    
            Properties prop = new Properties();  //map
            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);
        }
    
    }