Maven的User管理JSP-CRUD

作业………………………….

1: 环境搭建

    安装maven  ： 模版webapp创建项目，并且建立以下项目结构：

image

2：工具类

package utils;

import java.sql.*;

public class JdbcUtils {
    /**
     * 可以把几个字符串定义成常量：用户名，密码，URL，驱动类
     */
    private static final String USER = "root";
    private static final String PWD = "root";
    private static final String URL = "jdbc:mysql://127.0.0.1:3306/day01?useUnicode=true&characterEncoding=utf8&serverTimezone=UTC";
    private static final String DRIVER= "com.mysql.jdbc.Driver";
    /**
    * 注册驱动
    */
    static{
        try {
            Class.forName(DRIVER);
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
    }
    /**
    * 得到数据库的连接
     * @throws SQLException
     * @return
    */
    public static Connection getConnection() throws SQLException {
        return DriverManager.getConnection(URL, USER, PWD);
    }
    /**
    * 关闭所有打开的资源
    */
    public static void close(Connection conn, Statement stmt) {
        if(stmt!=null) {
            try {
                stmt.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        if(conn!=null) {
            try {
                conn.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
    /**
    * 关闭所有打开的资源
    */
    public static void close(Connection conn, Statement stmt, ResultSet rs) {
        if(rs!=null) {
            try {
                rs.close();
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
        close(conn, stmt);
    }
}

3：依赖

<dependencies>
    <dependency>
      <groupId>junit</groupId>
      <artifactId>junit</artifactId>
      <version>4.11</version>
      <scope>test</scope>
    </dependency>

    <dependency>
      <groupId>mysql</groupId>
      <artifactId>mysql-connector-java</artifactId>
      <version>8.0.20</version>
    </dependency>

    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>javax.servlet-api</artifactId>
      <version>4.0.1</version>
      <scope>provided</scope>
    </dependency>

    <dependency>
      <groupId>javax.servlet.jsp</groupId>
      <artifactId>javax.servlet.jsp-api</artifactId>
      <version>2.3.3</version>
      <scope>provided</scope>
    </dependency>
    <dependency>
      <groupId>javax.servlet</groupId>
      <artifactId>jstl</artifactId>
      <version>1.2</version>
    </dependency>
    <dependency>
      <groupId>org.projectlombok</groupId>
      <artifactId>lombok</artifactId>
      <version>1.18.12</version>
      <scope>provided</scope>
    </dependency>

  </dependencies>

4：编码

       4.1 实体

@Data
public class User {
    private Integer uid;
    private String username;
    private String password;
}

       4.2 dao

/**
 * @program: day01-maven
 * @description:
 * @author: Mr.Dai
 * @create: 2020-06-08 22:50
 **/
public interface UserDao {

    User findUserById(Integer uid) throws SQLException;

    Integer updateUserById(Integer uid,String username,String password);

    void deleteUserById(Integer uid);

    void addUser();
}

public class UserDaoImpl implements UserDao {

    @Override
    public User findUserById(Integer uid) throws SQLException {
        Connection connection = JdbcUtils.getConnection();
        PreparedStatement statement = connection.prepareStatement("select * from user where uid=?");
        statement.setInt(1,uid);
        ResultSet resultSet = statement.executeQuery();
        User user = new User();
        while(resultSet.next()){
            user.setUid(resultSet.getInt(1));
            user.setUsername(resultSet.getString(2));
            user.setPassword(resultSet.getString(3));
        }
        return user;
    }

    @Override
    public Integer updateUserById(Integer uid, String username, String password) {
        return null;
    }

    @Override
    public void deleteUserById(Integer uid) {

    }

    @Override
    public void addUser() {

    }
}

        4.3 service

public class UserServiceImpl implements service.UserService {
    private Logger logger=Logger.getLogger(UserService.class.getName());

    private UserDao dao=new UserDaoImpl();
    @Override
    public User findUserById(Integer uid) {
        User user=null;
        try {
            user=dao.findUserById(uid);
        } catch (SQLException throwables) {
            logger.log(Level.SEVERE,"查询失败！");
            throwables.printStackTrace();
        }
        return user;
    }
}

5：前端

<%@ page import="domain.User" %>
<%@ page import="java.util.List" %>
<%@ page import="java.util.Arrays" %>
<%@ page language="java" contentType="text/html; charset=utf-8"
         pageEncoding="utf-8"%>
<%
    String path = request.getContextPath();
    String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
    <base href="<%=basePath%>">
    <title>??</title>
    <meta http-equiv="pragma" content="no-cache">
    <meta http-equiv="cache-control" content="no-cache">
    <meta http-equiv="expires" content="0">
    <meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
    <meta http-equiv="description" content="This is my page">
</head>
<body>
<form action="findUByUid" method="post">
    <label for="uid">查询用户的id</label>
    <input id="uid" type="text" name="uid" value=" " >
    <input type="submit" value="查询">
</form>
<table border="1">
           <tr>
               <td>id</td>
              <td>name</td>
              <td>creator</td>
              <td>createTime</td>
           </tr>
             <%
                 User user = new User();
                 for(User tl:(List<User>)pageContext.getAttribute("userlist")!=null?(List<User>)pageContext.getAttribute("userlist"): Arrays.asList(user))
                {%>
               <tr>
                   <td><%=tl.getUid()%></td>
                  <td><%=tl.getUsername() %></td>
                  <td><%=tl.getPassword() %></td>
                   <td><%=(List<User>)pageContext.getAttribute("userlist")%></td>
               </tr>
                <%}
          %>
       </table>
</body>
</html>



web.xml

<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns="http://java.sun.com/xml/ns/javaee"
         xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
         xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
                               http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd"
         version="2.5">
  <display-name>Archetype Created Web Application</display-name>
  <welcome-file-list>
    <welcome-file>index.jsp</welcome-file>
  </welcome-file-list>
  <servlet>
    <servlet-name>findUserServlet</servlet-name>
    <servlet-class>servlet.FindUserServlet</servlet-class>
    <load-on-startup>1</load-on-startup>
  </servlet>
  <servlet-mapping>
    <servlet-name>findUserServlet</servlet-name>
    <url-pattern>/findUByUid</url-pattern>
  </servlet-mapping>
  <filter>
    <filter-name>characterFilter</filter-name>
    <filter-class>filter.CharacterFilter</filter-class>
  </filter>
  <filter-mapping>
    <filter-name>characterFilter</filter-name>
    <url-pattern>/*</url-pattern>
  </filter-mapping>

</web-app>


package servlet;

import domain.User;
import service.UserService;
import service.impl.UserServiceImpl;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.Arrays;

/**
 * @program: day01-maven
 * @description:
 * @author: Mr.Dai
 * @create: 2020-06-08 23:17
 **/
public class FindUserServlet extends HttpServlet {

    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        super.doPost(req,resp);
    }

    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        String uid = req.getParameter("uid");
        UserService userService  = new UserServiceImpl();
        User user = userService.findUserById(Integer.parseInt(uid.trim()));
        System.out.println(user.getUsername());
        req.setAttribute("userlist", Arrays.asList(user));
        req.getRequestDispatcher("/index.jsp").forward(req,resp);
    }
}
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原文地址：https://www.cnblogs.com/dgwblog/p/13069772.html