通过配置文件访问数据库
时间：2021-05-22 10:41:50
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1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html> 4 <html> 5 <head> 6 <meta charset="UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <form action="loginCheck" method="post"> 11 用户名:<input type="text" placeholder="请输入用户名" name="uname"><br> 12 密码:<input type="password" placeholder="请输入密码" name="pwd"><br> 13 <input type="submit" value="登录"> 14 <input type="reset" value="重置"> 15 </form> 16 </body> 17 </html>
1 url=jdbc:mysql://localhost:3306/db3 2 user=root 3 password=root 4 driver=com.mysql.jdbc.Driver
1 package util; 2 3 import java.io.FileNotFoundException; 4 import java.io.FileReader; 5 import java.io.IOException; 6 import java.net.URL; 7 import java.sql.Connection; 8 import java.sql.DriverManager; 9 import java.sql.ResultSet; 10 import java.sql.SQLException; 11 import java.sql.Statement; 12 import java.util.Properties; 13 14 /** 15 * <p>Title: JDBCUtils</p> 16 * <p>Description: JDBC工具类</p> 17 * @author: 丁帅帅 18 * @date: 2021-5-20 16:06:47 19 * @version v1.0 20 */ 21 public class JDBCUtils { 22 private static String url; 23 private static String user; 24 private static String password; 25 private static String driver; 26 27 static { 28 try { 29 Properties pro =new Properties(); 30 ClassLoader classLoader=JDBCUtils.class.getClassLoader(); 31 URL res=classLoader.getResource("jdbc.properties"); 32 String path=res.getPath(); 33 34 pro.load(new FileReader(path)); 35 url=pro.getProperty("url"); 36 user=pro.getProperty("user"); 37 password=pro.getProperty("password"); 38 driver=pro.getProperty("driver"); 39 40 Class.forName(driver); 41 } catch (FileNotFoundException e) { 42 43 e.printStackTrace(); 44 } catch (IOException e) { 45 46 e.printStackTrace(); 47 } catch (ClassNotFoundException e) { 48 49 e.printStackTrace(); 50 } 51 } 52 53 public static Connection getConnection() throws SQLException { 54 return DriverManager.getConnection(url,user,password); 55 } 56 57 58 public static void close(Statement stmt,Connection conn) { 59 if(stmt!=null) { 60 try { 61 stmt.close(); 62 } catch (SQLException e) { 63 // TODO Auto-generated catch block 64 e.printStackTrace(); 65 } 66 if(conn!=null) { 67 try { 68 conn.close(); 69 } catch (SQLException e) { 70 // TODO Auto-generated catch block 71 e.printStackTrace(); 72 } 73 } 74 75 76 } 77 } 78 79 public static void close(ResultSet rs,Statement pstmt,Connection conn) { 80 if(rs!=null) { 81 try { 82 rs.close(); 83 } catch (SQLException e) { 84 85 e.printStackTrace(); 86 } 87 } 88 89 if(pstmt!=null) { 90 try { 91 pstmt.close(); 92 } catch (SQLException e) { 93 94 e.printStackTrace(); 95 } 96 if(conn!=null) { 97 try { 98 conn.close(); 99 } catch (SQLException e) { 100 101 e.printStackTrace(); 102 } 103 } 104 105 } 106 } 107 108 }
1 package javabean; 2 3 import java.sql.Connection; 4 import java.sql.PreparedStatement; 5 import java.sql.ResultSet; 6 import java.sql.SQLException; 7 8 import util.JDBCUtils; 9 10 /** 11 * <p>Title: user</p> 12 * <p>Description: </p> 13 * @author: 丁帅帅 14 * @date: 2021-5-21 22:23:49 15 * @version v1.0 16 */ 17 public class user { 18 private String name; 19 private int password; 20 private Connection conn=null; 21 private PreparedStatement pstmt=null; 22 private ResultSet rs=null; 23 public user(String name, int password) { 24 this.name = name; 25 this.password = password; 26 } 27 public String getName() { 28 return name; 29 } 30 public void setName(String name) { 31 this.name = name; 32 } 33 public int getPassword() { 34 return password; 35 } 36 public void setPassword(int password) { 37 this.password = password; 38 } 39 @Override 40 public String toString() { 41 return "user name=" + name + ", password=" + password; 42 } 43 public boolean login() { 44 try { 45 conn=JDBCUtils.getConnection(); 46 String sql="select *from user where name=? and password=?"; 47 pstmt=conn.prepareStatement(sql); 48 49 pstmt.setString(1,name); 50 pstmt.setInt(2,password); 51 rs=pstmt.executeQuery(); 52 /* 53 * if(rs.next()) { return true; }else { return false; } 54 */ 55 return rs.next(); 56 } catch (SQLException e) { 57 58 e.printStackTrace(); 59 }finally { 60 JDBCUtils.close(rs, pstmt, conn); 61 } 62 return false; 63 } 64 65 }
1 package com.servlet; 2 3 import java.io.IOException; 4 5 import javax.servlet.ServletException; 6 import javax.servlet.annotation.WebServlet; 7 import javax.servlet.http.HttpServlet; 8 import javax.servlet.http.HttpServletRequest; 9 import javax.servlet.http.HttpServletResponse; 10 11 import javabean.user; 12 13 14 @WebServlet("/Jsp_Servlet/loginCheck") 15 public class LoginCheck extends HttpServlet{ 16 @Override 17 protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 18 19 doGet(req, resp); 20 } 21 @Override 22 protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException { 23 String uname=req.getParameter("uname"); 24 int pwd=Integer.parseInt(req.getParameter("pwd")) ; 25 user user = new user(uname, pwd); 26 boolean flag=user.login(); 27 if(flag) { 28 req.setAttribute("name", uname); 29 req.getRequestDispatcher("Welcome.jsp").forward(req, resp); 30 } 31 else { 32 //System.out.println(user.toString()); 33 req.getRequestDispatcher("login.jsp").forward(req, resp); 34 } 35 36 } 37 }
1 <%@ page language="java" contentType="text/html; charset=UTF-8" 2 pageEncoding="UTF-8"%> 3 <!DOCTYPE html> 4 <html> 5 <head> 6 <meta charset="UTF-8"> 7 <title>Insert title here</title> 8 </head> 9 <body> 10 <h1>欢迎您,<%=request.getAttribute("name") %></h1> 11 </body> 12 </html>
原文：https://www.cnblogs.com/dss-99/p/14797748.html
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