servlet-mysql实现简单用户登录注册
Posted feifei
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环境：IDEA Maven
效果截图：
项目结构：
类说明：
ConnectionUtil：负责数据库连接和释放
UserDao：数据库增删改查操作
User：用户Bean，只用注册和登录的话可以不要
UserServlet：Servlet，控制页面跳转
前端就不放了大同小异
1 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 }
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 }
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 }
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 }
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>
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