servlet-mysql实现简单用户登录注册

import cn.flyuz.pan.entity.User; 2 import cn.flyuz.pan.util.Base; 3 import cn.flyuz.pan.util.ConnectionUtil; 4 5 import java.sql.Connection; 6 import java.sql.PreparedStatement; 7 import java.sql.ResultSet; 8 import java.sql.SQLException; 9 import java.util.ArrayList; 10 import java.util.List; 11 12 public class UserDao { 13 private Connection getConn() { 14 ConnectionUtil connectionUtil = new ConnectionUtil(); 15 return connectionUtil.getConn(); 16 } 17 public boolean login(String user, String pw) { 18 Connection conn = getConn(); 19 String sql = "select * from login where user=? and pw=?"; 20 21 try { 22 PreparedStatement ps =conn.prepareStatement(sql); 23 ps.setString(1,user); 24 ps.setString(2,pw); 25 ResultSet rs = ps.executeQuery(); 26 if (rs.next()){ 27 ps.close(); 28 rs.close(); 29 return true; 30 } 31 } catch (SQLException e) { 32 e.printStackTrace(); 33 } 34 return false; 35 } 36 37 public String reg(String user, String pw) { 38 Connection conn = getConn(); 39 String sql1= "select * from login where user = ?"; 40 String sql = "insert into login(user,pw) values (?,?)"; 41 42 try { 43 PreparedStatement pss = conn.prepareStatement(sql1); 44 pss.setString(1,user); 45 ResultSet rs = pss.executeQuery(); 46 if (!rs.next()){ 47 PreparedStatement ps = conn.prepareStatement(sql); 48 ps.setString(1,user); 49 ps.setString(2,pw); 50 ps.executeUpdate(); 51 return Base.registerSuccess; 52 }else{ 53 return Base.registerFalse; 54 } 55 } catch (SQLException e) { 56 e.printStackTrace(); 57 } 58 return Base.registerFalse; 59 } 60 61 public void del(String user) { 62 Connection conn = getConn(); //获取连接 63 String sql = "delete from login where user = ?";//sql语句 64 try { 65 PreparedStatement ps = conn.prepareStatement(sql); 66 ps.setString(1,user); 67 ps.executeUpdate(); 68 } catch (SQLException e) { 69 e.printStackTrace(); 70 } 71 } 72 // public List<User> getAll() { 73 // Connection conn = getConn(); 74 // String sql = "select * from login"; 75 // try { 76 // PreparedStatement ps = conn.prepareStatement(sql); 77 // ResultSet rs = ps.executeQuery(); 78 // List<User> userList = new ArrayList<>(); 79 // while(rs.next()) { 80 // User user1 = new User(); 81 // user1.setUser(rs.getString("user")); 82 // user1.setPw(rs.getString("pw")); 83 // userList.add(user1); 84 // } 85 // return userList; 86 // } catch (SQLException e) { 87 // e.printStackTrace(); 88 // } 89 // return null; 90 // } 91 // public void update(String user,String pw){ 92 // Connection conn = getConn(); //获取连接 93 // String sql = "update login set user = ?,pw = ? where id = ?"; //sql语句 94 // try { 95 // PreparedStatement ps = conn.prepareStatement(sql); 96 // //设置参数 97 // ps.setString(1,user); 98 // ps.setString(2,pw); 99 // ps.executeUpdate(); 100 // 101 // } catch (SQLException e) { 102 // e.printStackTrace(); 103 // } 104 // } 105 } UserDao

  1 import cn.flyuz.pan.dao.UserDao;
  2 import cn.flyuz.pan.util.Base;
  3 
  4 import javax.servlet.ServletException;
  5 import javax.servlet.annotation.WebServlet;
  6 import javax.servlet.http.HttpServlet;
  7 import javax.servlet.http.HttpServletRequest;
  8 import javax.servlet.http.HttpServletResponse;
  9 import java.io.IOException;
 10 
 11 
 12 @WebServlet(name = "UserServlet", urlPatterns = "/loginServlet")
 13 public class UserServlet extends HttpServlet {
 14     private UserDao userDao = new UserDao();
 15 
 16     protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 17         response.setContentType("text/html;charset=utf-8");
 18         request.setCharacterEncoding("utf-8");
 19         String type = request.getParameter("type");
 20 
 21         switch (type) {
 22             case "login":
 23                 login(request, response);
 24                 break;
 25             case "reg":
 26                 reg(request, response);
 27                 break;
 28 //            case "del":
 29 //                del(request, response);
 30 //                break;
 31 //            case "getAll":
 32 //                getAll(request, response);
 33 //                break;
 34         }
 35     }
 36     protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 37         this.doPost(request, response);
 38     }
 39 
 40 
 41     private void login(HttpServletRequest request, HttpServletResponse response) {
 42         String user = request.getParameter("user");
 43         String pw = request.getParameter("pw");
 44 
 45         boolean user_login = userDao.login(user, pw);
 46         try {
 47             if (user_login) {
 48                 request.getRequestDispatcher("index/index.jsp").forward(request, response);
 49             } else {
 50                 String msg = "登陆失败";
 51                 request.getSession().setAttribute("msg", msg);
 52                 request.getRequestDispatcher("index/login.jsp").forward(request, response);
 53             }
 54         } catch (ServletException | IOException e) {
 55             e.printStackTrace();
 56         }
 57     }
 58 
 59     private void reg(HttpServletRequest request, HttpServletResponse response) {
 60         String user = request.getParameter("user");
 61         String pw = request.getParameter("pw");
 62 
 63         String rs = userDao.reg(user, pw);
 64         if (rs.equals(Base.registerSuccess)) {
 65             try {
 66                 request.getRequestDispatcher("index/login.jsp").forward(request, response);
 67             } catch (ServletException | IOException e) {
 68                 e.printStackTrace();
 69             }
 70         } else if (rs.equals(Base.registerFalse) || rs.equals(Base.registerRepeated)) {
 71             try {
 72                 String msg = "注册失败";
 73                 request.getSession().setAttribute("msg", msg);
 74                 request.getRequestDispatcher("index/register.jsp").forward(request, response);
 75             } catch (ServletException | IOException e) {
 76                 e.printStackTrace();
 77             }
 78         }
 79     }
 80 //    private void del(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
 81 //        String user = request.getParameter("user");
 82 //        try {
 83 //            userDao.del(user);
 84 //            request.getSession().setAttribute("msg", "删除成功！");
 85 //            request.getRequestDispatcher("index/index.jsp").forward(request, response);
 86 //        } catch (Exception e) {
 87 //            e.printStackTrace();
 88 //            request.getSession().setAttribute("msg", "删除失败！");
 89 //            request.getRequestDispatcher("index/index.jsp").forward(request, response);
 90 //        }
 91 //    }
 92 //    private void getAll(HttpServletRequest request, HttpServletResponse response) {
 93 //        request.getSession().setAttribute("userList", userDao.getAll());
 94 //        try {
 95 //            request.getRequestDispatcher("index/index.jsp").forward(request, response);
 96 //        } catch (ServletException | IOException e) {
 97 //            e.printStackTrace();
 98 //        }
 99 //    }
100 }

UserServlet

 1 import java.sql.DriverManager;
 2 import java.sql.SQLException;
 3 import java.sql.Connection;
 4 
 5 public class ConnectionUtil {
 6     private String dbDriver = "com.mysql.cj.jdbc.Driver";
 7     private String dbUrl="jdbc:mysql://localhost:3306/login?characterEncoding=utf-8&useSSL=false&serverTimezone=UTC ";
 8     private String dbUser="root";
 9     private String dbPw="123456";
10     private static Connection conn = null;
11 
12     public Connection getConn() {
13         try{
14             Class.forName(dbDriver);
15             conn = DriverManager.getConnection(dbUrl,dbUser,dbPw);
16         }catch(ClassNotFoundException|SQLException e){
17             e.printStackTrace();
18         }
19         return conn;
20     }
21 
22     public static void conClose(){
23         if(conn != null){
24             try {
25                 conn.close();
26             } catch (SQLException e) {
27                 e.printStackTrace();
28             }
29         }
30     }
31 }

ConnectionUtil

 1 import cn.flyuz.pan.util.ConnectionUtil;
 2 
 3 import javax.servlet.ServletContextEvent;
 4 import javax.servlet.ServletContextListener;
 5 import javax.servlet.annotation.WebListener;
 6 
 7 @WebListener
 8 public class DBCloseListener implements ServletContextListener{
 9     @Override
10     public void contextDestroyed(ServletContextEvent arg0) {
11         ConnectionUtil.conClose();
12     }
13 
14     @Override
15     public void contextInitialized(ServletContextEvent arg0) {
16     }
17 }

DBCloseListener

 1 <?xml version="1.0" encoding="UTF-8"?>
 2 <project xmlns="http://maven.apache.org/POM/4.0.0"
 3          xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
 4          xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
 5     <modelVersion>4.0.0</modelVersion>
 6 
 7     <groupId>groupId</groupId>
 8     <artifactId>flyuzP</artifactId>
 9     <version>1.0-SNAPSHOT</version>
10     <dependencies>
11     <dependency>
12         <groupId>javax.servlet</groupId>
13         <artifactId>jstl</artifactId>
14         <version>1.2</version>
15     </dependency>
16 
17     <dependency>
18         <groupId>taglibs</groupId>
19         <artifactId>standard</artifactId>
20         <version>1.1.2</version>
21     </dependency>
22 
23     <dependency>
24         <groupId>mysql</groupId>
25         <artifactId>mysql-connector-java</artifactId>
26         <version>8.0.12</version>
27     </dependency>
28     </dependencies>
29     <build>
30         <plugins>
31             <plugin>
32                 <groupId>org.apache.maven.plugins</groupId>
33                 <artifactId>maven-compiler-plugin</artifactId>
34                 <version>2.5</version>
35                 <configuration>
36                     <source>1.8</source>
37                     <target>1.8</target>
38                     <encoding>utf8</encoding>
39                 </configuration>
40             </plugin>
41         </plugins>
42     </build>
43 
44 </project>

Maven

 

servlet-mysql实现简单用户登录注册

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