源码：
1、用户 CRUD servlet
1 package fafa.shop.controller; 2 import java.io.IOException; 3 import java.util.ArrayList; 4 import javax.servlet.ServletException; 5 import javax.servlet.http.HttpServlet; 6 import javax.servlet.http.HttpServletRequest; 7 import javax.servlet.http.HttpServletResponse; 8 import fafa.shop.service.User; 9 import fafa.shop.service.UserModel; 10 @SuppressWarnings("serial") 11 public class UserServ extends HttpServlet { 12 public void doGet(HttpServletRequest request, HttpServletResponse response) 13 throws ServletException, IOException { 14 request.setCharacterEncoding("GBK") ; 15 UserModel us = new UserModel() ; 16 String type= request.getParameter("type"); 17 if (type.equals("add")){ 18 String uid = null ; 19 String username = request.getParameter("username") ; 20 String password = request.getParameter("password") ; 21 String email = request.getParameter("email") ; 22 User user = new User(uid, username, password, email) ; 23 if (us.insertUser(user)){ 24 ArrayList<User> all = us.getAll() ; 25 request.setAttribute("user", all) ; 26 request.getRequestDispatcher("/index.jsp").forward(request, response) ; 27 }else{ 28 request.setAttribute("error", "用户添加失败") ; 29 request.getRequestDispatcher("/index.jsp").forward(request, response) ; 30 } 31 }else if (type.equals("mod")){ 32 String uid = request.getParameter("uid") ; 33 ArrayList<User> all = us.getOne(uid) ; 34 if (all != null){ 35 request.setAttribute("user", all) ; 36 request.getRequestDispatcher("/WEB-INF/update.jsp").forward(request, response) ; 37 }else { 38 request.setAttribute("error", "用户不存在！！！") ; 39 request.getRequestDispatcher("/WEB-INF/update.jsp").forward(request, response) ; 40 } 41 42 }else if (type.equals("update")){ 43 String uid = request.getParameter("uid") ; 44 String username = request.getParameter("username") ; 45 String password = request.getParameter("password") ; 46 String email = request.getParameter("email") ; 47 User user = new User(uid, username, password, email) ; 48 if (us.updateUser(user)){ 49 request.setAttribute("updateSuccess", "数据更新成功！") ; 50 request.getRequestDispatcher("/index.jsp").forward(request, response) ; 51 }else{ 52 request.setAttribute("updateError", "数据更新失败！") ; 53 request.getRequestDispatcher("/index.jsp").forward(request, response) ; 54 } 55 }else if (type.equals("del")){ 56 String uid = request.getParameter("uid") ; 57 58 if (us.delUser(uid)){ 59 request.setAttribute("delSuccess", "数据删除成功！") ; 60 request.getRequestDispatcher("/index.jsp").forward(request, response) ; 61 }else{ 62 request.setAttribute("delError", "数据删除失败！") ; 63 request.getRequestDispatcher("/index.jsp").forward(request, response) ; 64 } 65 } 66 67 } 68 public void doPost(HttpServletRequest request, HttpServletResponse response) 69 throws ServletException, IOException { 70 this.doGet(request, response) ; 71 } 72 73 }
2、user bean 类
1 package fafa.shop.service; 2 3 public class User { 4 private String uid ; 5 private String username ; 6 private String password ; 7 private String email ; 8 9 public User() { 10 super(); 11 } 12 public User(String uid ,String username, String password, String email) { 13 super(); 14 this.uid = uid ; 15 this.username = username; 16 this.password = password; 17 this.email = email; 18 } 19 public String getUid() { 20 return uid; 21 } 22 public void setUid(String uid) { 23 this.uid = uid; 24 } 25 public String getUsername() { 26 return username; 27 } 28 public void setUsername(String username) { 29 this.username = username; 30 } 31 public String getPassword() { 32 return password; 33 } 34 public void setPassword(String password) { 35 this.password = password; 36 } 37 public String getEmail() { 38 return email; 39 } 40 public void setEmail(String email) { 41 this.email = email; 42 } 43 }
3、userModel 类 和 数据库连接类
1 package fafa.shop.service; 2 3 import java.sql.*; 4 import java.util.ArrayList; 5 6 import fafa.shop.util.DBUtil; 7 8 public class UserModel { 9 private Connection conn = null ; 10 private PreparedStatement ps = null ; 11 private ResultSet rs = null ; 12 13 //插入用户 14 public boolean insertUser(User user){ 15 boolean flag = false ; 16 try { 17 this.conn = DBUtil.getConnection() ; 18 String sql = "INSERT INTO user(uid,username,password,email) VALUES(?,?,?,?)" ; 19 this.ps = this.conn.prepareStatement(sql) ; 20 this.ps.setString(1, null) ; 21 this.ps.setString(2, user.getUsername()) ; 22 this.ps.setString(3, user.getPassword()) ; 23 this.ps.setString(4, user.getEmail()) ; 24 this.ps.executeUpdate() ; 25 flag = true ; 26 } catch (Exception e) { 27 e.printStackTrace(); 28 }finally{ 29 try { 30 this.conn.close() ; 31 } catch (SQLException e) { 32 e.printStackTrace(); 33 } 34 try { 35 this.ps.close(); 36 } catch (SQLException e) { 37 e.printStackTrace(); 38 } 39 } 40 41 return flag ; 42 } 43 44 //取得所有用户 45 public ArrayList<User> getAll(){ 46 ArrayList<User> all = new ArrayList<User>() ; 47 try { 48 this.conn = DBUtil.getConnection() ; 49 String sql = "SELECT uid, username, password, email FROM user" ; 50 this.ps = this.conn.prepareStatement(sql) ; 51 this.rs = this.ps.executeQuery() ; 52 while(this.rs.next()){ 53 User user = new User() ; 54 user.setUid(rs.getString("uid")) ; 55 user.setUsername(rs.getString("username")) ; 56 user.setPassword(rs.getString("password")) ; 57 user.setEmail(rs.getString("email")) ; 58 all.add(user) ; 59 } 60 61 } catch (Exception e) { 62 e.printStackTrace(); 63 }finally{ 64 try { 65 this.conn.close() ; 66 this.ps.close() ; 67 this.rs.close() ; 68 } catch (SQLException e) { 69 e.printStackTrace(); 70 } 71 } 72 73 return all ; 74 } 75 76 //取一条数据 77 public ArrayList<User> getOne(String uid){ 78 ArrayList<User> all = new ArrayList<User>() ; 79 try { 80 this.conn = DBUtil.getConnection() ; 81 String sql = "SELECT uid, username, password, email FROM user WHERE uid=?" ; 82 this.ps = this.conn.prepareStatement(sql) ; 83 this.ps.setString(1, uid) ; 84 this.rs = this.ps.executeQuery() ; 85 while(this.rs.next()){ 86 User user = new User() ; 87 user.setUid(rs.getString("uid")) ; 88 user.setUsername(rs.getString("username")) ; 89 user.setPassword(rs.getString("password")) ; 90 user.setEmail(rs.getString("email")) ; 91 all.add(user) ; 92 } 93 94 } catch (Exception e) { 95 e.printStackTrace(); 96 }finally{ 97 try { 98 this.conn.close() ; 99 this.ps.close() ; 100 this.rs.close() ; 101 } catch (SQLException e) { 102 e.printStackTrace(); 103 } 104 } 105 return all ; 106 } 107 108 //更新数据 109 public boolean updateUser(User user){ 110 boolean flag = false ; 111 try { 112 this.conn = DBUtil.getConnection() ; 113 String sql = "UPDATE user SET username=?, password=?, email=? WHERE uid=?" ; 114 this.ps = this.conn.prepareStatement(sql) ; 115 this.ps.setString(1, user.getUsername()) ; 116 this.ps.setString(2, user.getPassword()) ; 117 this.ps.setString(3, user.getEmail()) ; 118 this.ps.setString(4, user.getUid()) ; 119 this.ps.executeUpdate() ; 120 flag = true ; 121 } catch (Exception e) { 122 e.printStackTrace(); 123 }finally{ 124 try { 125 this.conn.close() ; 126 } catch (SQLException e) { 127 e.printStackTrace(); 128 } 129 try { 130 this.ps.close(); 131 } catch (SQLException e) { 132 e.printStackTrace(); 133 } 134 } 135 return flag ; 136 } 137 138 //删除用户 139 public boolean delUser(String uid){ 140 boolean flag = false ; 141 try { 142 this.conn = DBUtil.getConnection() ; 143 String sql = "DELETE FROM user WHERE uid=?" ; 144 this.ps = this.conn.prepareStatement(sql) ; 145 this.ps.setInt(1, Integer.parseInt(uid)) ; 146 this.ps.executeUpdate() ; 147 flag = true ; 148 } catch (Exception e) { 149 e.printStackTrace(); 150 }finally{ 151 try { 152 this.conn.close() ; 153 } catch (SQLException e) { 154 e.printStackTrace(); 155 } 156 try { 157 this.ps.close(); 158 } catch (SQLException e) { 159 e.printStackTrace(); 160 } 161 } 162 return flag ; 163 } 164 }
1 package fafa.shop.util; 2 3 import java.sql.*; 4 5 public class DBUtil { 6 private static final String DBDRIVER = "org.gjt.mm.mysql.Driver" ; 7 private static final String DBURL = "jdbc:mysql://localhost:3306/test" ; 8 private static final String DBUSER = "root" ; 9 private static final String DBPASS = "123456" ; 10 11 private static Connection conn = null ; 12 13 //外部取得连接 14 public static Connection getConnection() throws Exception { 15 Class.forName(DBDRIVER) ; 16 conn = DriverManager.getConnection(DBURL, DBUSER, DBPASS) ; 17 return conn ; 18 } 19 20 //关闭连接 21 public static void close(ResultSet rs, Statement ps, Connection ct){ 22 try { 23 if (rs!=null){ 24 rs.close() ; 25 } 26 } catch (SQLException e) { 27 e.printStackTrace(); 28 } 29 try { 30 if (ps!=null){ 31 ps.close() ; 32 } 33 } catch (SQLException e) { 34 e.printStackTrace(); 35 } 36 try { 37 if (ct!=null){ 38 ct.close() ; 39 } 40 } catch (SQLException e) { 41 e.printStackTrace(); 42 } 43 } 44 }
这样就完成成了数据的CRUD ，我现在是初学者啊，没办法只能这样练练手，希望能更快上手.
本来是使用三种数据库 oracle、mssql 、mysql 完成的。
以上还少了功能：分页、上传文件、支付、 等等。
当然现在很多企业也不再会这样写代码了，基本都是用框架了。所以下面的学习中心转移到框架 和 基础加深了。