这里是学习了Servlet后结合数据库进行增删查改–登录等作为练手项目非常适合
准备工作：
1.数据准备
这张表是用户表，用于登录
CREATE TABLE `users` (
`id` int NOT NULL AUTO_INCREMENT,
`username` varchar(25) DEFAULT NULL,
`password` varchar(20) DEFAULT NULL,
`phone` varchar(11) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=15 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
这张表是具体的用户数据
CREATE TABLE `user` (
`id` int NOT NULL AUTO_INCREMENT,
`username` varchar(25) DEFAULT NULL,
`name` varchar(10) DEFAULT NULL,
`gender` varchar(3) DEFAULT NULL,
`state` varchar(10) DEFAULT NULL,
`code` varchar(25) DEFAULT NULL,
`email` varchar(20) DEFAULT NULL,
PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=57 DEFAULT CHARSET=utf8mb4 COLLATE=utf8mb4_0900_ai_ci;
数据根据需要自行插入
2. 数据库连接
这里是properties文件，需要在resource文件夹下
driver = com.mysql.cj.jdbc.Driver
url = jdbc:mysql://localhost:3306/db_test3?useUnicode=true&characterEncoding=utf8&useSSL=false&serverTimezone=UTC
username = root
password = 123456
initialSize=5
minIdle=5
maxActive=10
maxWait=3000
德鲁伊数据库连接
public class DruidUtils {
private static Properties properties = new Properties();
private static DruidDataSource dataSource = null;
static {
try {
properties.load(DruidUtils.class.getResourceAsStream("/db.properties"));
dataSource = (DruidDataSource) DruidDataSourceFactory.createDataSource(properties);
dataSource.setDriverClassName(properties.getProperty("driver"));
dataSource.setUrl(properties.getProperty("url"));
dataSource.setUsername(properties.getProperty("username"));
dataSource.setPassword(properties.getProperty("password"));
} catch (IOException e) {
e.printStackTrace();
} catch (Exception e) {
e.printStackTrace();
}
}
public static Connection getConn() {
try {
return dataSource.getConnection();
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
//这里是为第三方的DButil建立数据源
public static DataSource getdataSource(){
return dataSource;
}
}
3.登录
userDao
public interface UserDao {
/**
* 登录
* @param aname 账号
* @param apass 密码
* @return
*/
User login(String aname, String apass);
}
Dao层实现类
public class UserDaoImpl implements UserDao {
private static QueryRunner queryRunner = new QueryRunner(DruidUtils.getdataSource());
//登录
@Override
public User login(String aname, String apass) {
String sql = "select * from admin_user where aname = ? and apass = ?";
try {
return queryRunner.query(sql,new BeanHandler<User>(User.class),aname,apass);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
}
Service业务层
public interface UserService {
User login(String aname, String apass);
}
Service实现类
public class UserServiceImpl implements UserService {
private static UserDao userDao = new UserDaoImpl();
@Override
public User login(String aname, String apass) {
User user = userDao.login(aname, apass);
return user;
}
}
Controller层
package com.fjp.usersys.controller;
import com.fjp.usersys.pojo.User;
import com.fjp.usersys.service.UserService;
import com.fjp.usersys.service.impl.UserServiceImpl;
import javax.servlet.*;
import javax.servlet.http.*;
import javax.servlet.annotation.*;
import java.io.IOException;
@WebServlet(name = "UserServlet", value = "/UserServlet")
public class UserServlet extends HttpServlet {
private static UserService userService = new UserServiceImpl();
private static UsersServlet usersServlet = new UsersServlet();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
login(request, response);
response.sendRedirect("UsersServlet");
}
protected void login(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=UTF-8");
String uname = request.getParameter("uname");
String pass = request.getParameter("pass");
User user = userService.login(uname, pass);
request.setAttribute("user", user);
// 跳转到用户列表页面
//request.getRequestDispatcher("UsersServlet").forward(request,response);
//response.getWriter().println("登录成功");
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
4.用户信息的增删查改
Dao层及实现类
public interface UsersDao {
/**
* 查找全部用户信息
* @return
*/
List<Users> findAll();
/**
* 通过id查找
* @param id
* @return
*/
Users findById(int id);
/**
* 更新
* @param users
* @return
*/
int updateUsers(Users users);
int deleteUsers(int id);
int addUser(Users users);
}
public class UsersDaoImpl implements UsersDao {
private static QueryRunner queryRunner = new QueryRunner(DruidUtils.getdataSource());
@Override
public List<Users> findAll() {
String sql = "select * from user";
try {
return queryRunner.query(sql,new BeanListHandler<Users>(Users.class));
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
@Override
public Users findById(int id) {
String sql = "select * from user where id = ?";
try {
return queryRunner.query(sql,new BeanHandler<Users>(Users.class),id);
} catch (SQLException e) {
e.printStackTrace();
}
return null;
}
@Override
public int updateUsers(Users users) {
String sql = "update user set username =? , name = ?, gender = ?, state =?, code =? , email =? where id =?";
try {
return queryRunner.update(sql ,users.getUsername(),users.getName(),users.getGender(),users.getState(),users.getCode(),users.getEmail(),users.getId());
} catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
@Override
public int deleteUsers(int id) {
String sql = "delete from user where id =?";
try {
return queryRunner.update(sql,id);
} catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
@Override
public int addUser(Users users) {
String sql = "insert into user values(?,?,?,?,?,?,?)";
try {
return queryRunner.update(sql, users.getId(),users.getUsername(),users.getName(),users.getGender(),users.getState(),users.getCode(),users.getEmail());
} catch (SQLException e) {
e.printStackTrace();
}
return 0;
}
}
Service层及实现类
public interface UsersService {
/**
* 查找全部
* @return
*/
List<Users> findAll();
/**
* id查找
* @param id
* @return
*/
Users findById(int id);
/**
* 更新
* @param users
* @return
*/
boolean updateUsers(Users users);
boolean deleteUsers(int id);
boolean addUsers(Users users);
}
public class UsersServiceImpl implements UsersService {
private static UsersDao usersDao = new UsersDaoImpl();
@Override
public List<Users> findAll() {
List<Users> users = usersDao.findAll();
return users;
}
@Override
public Users findById(int id) {
Users users = usersDao.findById(id);
return users;
}
@Override
public boolean updateUsers(Users users) {
int i = usersDao.updateUsers(users);
return i>0;
}
@Override
public boolean deleteUsers(int id) {
int i = usersDao.deleteUsers(id);
return i>0;
}
@Override
public boolean addUsers(Users users) {
int i = usersDao.addUser(users);
return i>0;
}
}
Controller层
@WebServlet(name = "UsersServlet", value = "/UsersServlet")
public class UsersServlet extends HttpServlet {
private static UsersService usersService = new UsersServiceImpl();
@Override
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=UTF-8");
String action = request.getParameter("action");
if (action == null) {
findAll(request, response);
}else if ("findById".equals(action)) {
findById(request, response);
}else if("updateUsers".equals(action)){
updateUsers(request, response);
}else if ("delete".equals(action)){
deleteUsers(request, response);
findAll(request, response);
}else if ("add".equals(action)) {
add(request, response);
}else if ("addUsers".equals(action)){
addUsers(request, response);
}
}
protected void findAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
List<Users> users = usersService.findAll();
PrintWriter writer = response.getWriter();
writer.print("<!DOCTYPE html>\n" +
"<html lang=\"en\">\n" +
"<head>\n" +
" <meta charset=\"UTF-8\">\n" +
" <title>用户管理</title>\n" +
"</head>\n" +
"<body>\n" +"<table align='center' width='85%' border='1'>\n" +
" <tr>\n" +
" <td>编号</td>\n" +
" <td>昵称</td>\n" +
" <td>姓名</td>\n" +
" <td>性别</td>\n" +
" <td>状态</td>\n" +
" <td>邀请码</td>\n" +
" <td>邮箱</td>\n" +
"<td>操作   <a href='UsersServlet?action=add'>新增</a></td>"+
" </tr>");
for (Users user : users) {
writer.print(" <tr>\n" +
" <td>"+user.getId()+"</td>\n" +
" <td>"+user.getUsername()+"</td>\n" +
" <td>"+user.getName()+"</td>\n" +
" <td>"+user.getGender()+"</td>\n" +
" <td>"+user.getState()+"</td>\n" +
" <td>"+user.getCode()+"</td>\n" +
" <td>"+user.getEmail()+"</td>\n" +
" <td><a href='UsersServlet?id="+user.getId()+"&action=findById'>修改</a>   <a href='UsersServlet?id="+user.getId()+"&action=delete'>删除</a></td>\n" +
" </tr>");
}
writer.print("</table>\n" +
"</body>\n" +
"</html>");
}
protected void updateUsers(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//findById(request, response);
String id = request.getParameter("id");
int uid = id == null ? 0: Integer.parseInt(id);
String username = request.getParameter("username");
String name = request.getParameter("name");
String gender = request.getParameter("gender");
String state = request.getParameter("state");
String code = request.getParameter("code");
String email = request.getParameter("email");
Users users = new Users();
users.setId(uid);
users.setUsername(username);
users.setName(name);
users.setGender(gender);
users.setState(state);
users.setCode(code);
users.setEmail(email);
boolean b = usersService.updateUsers(users);
if (b) {
response.sendRedirect("UsersServlet");
}
}
protected void findById(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String id = request.getParameter("id");
int uid = id== null?0: Integer.parseInt(id);
Users users = usersService.findById(uid);
PrintWriter writer = response.getWriter();
writer.print("<form method=\"post\" action=\"UsersServlet?action=updateUsers\">\n" +
" 编号：<input type=\"text\" name=\"id\"readonly=\"readonly\" value=\""+users.getId()+"\">\n" +
" 昵称：<input type=\"text\" name=\"username\" value=\""+users.getUsername()+"\">\n" +
" 姓名：<input type=\"text\" name=\"name\" value=\""+users.getName()+"\">\n" +
" 性别：<input type=\"text\" name=\"gender\" value=\""+users.getGender()+"\">\n" +
" 状态：<input type=\"text\" name=\"state\" value=\""+users.getState()+"\">\n" +
" 邀请码：<input type=\"text\" name=\"code\" value=\""+users.getCode()+"\">\n" +
" 邮箱：<input type=\"text\" name=\"email\" value=\""+users.getEmail()+"\">\n" +
" <input type=\"submit\" value=\"修改\">\n" +
" </form>");
//updateUsers(request, response);
//updateUsers(request, response);
}
protected void deleteUsers(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String id = request.getParameter("id");
int uid = id == null ? 0:Integer.parseInt(id);
boolean b = usersService.deleteUsers(uid);
}
protected void addUsers(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
String id = request.getParameter("id");
int uid = Integer.parseInt(id);
String username = request.getParameter("username");
String name = request.getParameter("name");
String gender = request.getParameter("gender");
String state = request.getParameter("state");
String code = request.getParameter("code");
String email = request.getParameter("email");
Users users = new Users();
users.setId(uid);
users.setUsername(username);
users.setName(name);
users.setGender(gender);
users.setState(state);
users.setCode(code);
users.setEmail(email);
boolean b = usersService.addUsers(users);
if (b) {
response.sendRedirect("UsersServlet");
}
}
protected void add(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
Users users = new Users();
PrintWriter writer = response.getWriter();
writer.print("<form method=\"post\" action=\"UsersServlet?action=addUsers\">\n" +
" 编号：<input type=\"text\" name=\"id\" value=\""+users.getId()+"\">\n" +
" 昵称：<input type=\"text\" name=\"username\" value=\""+users.getUsername()+"\">\n" +
" 姓名：<input type=\"text\" name=\"name\" value=\""+users.getName()+"\">\n" +
" 性别：<input type=\"text\" name=\"gender\" value=\""+users.getGender()+"\">\n" +
" 状态：<input type=\"text\" name=\"state\" value=\""+users.getState()+"\">\n" +
" 邀请码：<input type=\"text\" name=\"code\" value=\""+users.getCode()+"\">\n" +
" 邮箱：<input type=\"text\" name=\"email\" value=\""+users.getEmail()+"\">\n" +
" <input type=\"submit\" value=\"添加\">\n" +
" </form>");
}
@Override
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doGet(request, response);
}
}
4.前端
<%@ page contentType="text/html; charset=UTF-8" pageEncoding="UTF-8" %>
<!DOCTYPE html>
<html>
<head>
<title></title>
</head>
<body>
<form action="UserServlet" method="post">
用户名：<input type="text" name="uname"><br/>
密码：<input type="password" name="pass"><br/>
<input type="submit" value="登录">
</form>
</body>
</html>
需要的jar包
代码结构**
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