java web 添加 删除 修改 查询

于 2020-03-17 19:29:50 发布
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分类专栏： 笔记
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本文链接：https://blog.youkuaiyun.com/m0_46207738/article/details/104928228
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这篇博客介绍了如何在Java Web环境中实现学生信息的添加、查看/修改、删除功能。首先，需要导入相关jar包。接着，详细展示了StudentServlet类的各个方法，包括doPost和doGet，以及用于编辑、注册、查找、更新和删除学生的具体实现。每个操作都涉及到从请求中获取参数，调用Service层的方法，并根据操作结果返回相应的提示信息。

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——、需要导入jar包
如下五个jar包
在这里插入图片描述在这里插入图片描述
下载：http://mvnrepository.com
一、实现添加
在这里插入图片描述

<%--
  Created by IntelliJ IDEA.
  User: love
  Date: 2020/3/6
  Time: 8:24
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>

  <link rel="stylesheet" href="css/style.css">

  <script src="js/form.js"></script>

</head>
<body>

<div class="form" style="position:relative">
  <a href="/untitled/studentServlet?anhao=find">查询用户</a>
  <!--注册表单-->
  <div class="form_register" style="position:absolute">
    <form action="/untitled/studentServlet?anhao=reg" method="post">
      <h1>注册表单</h1>
      <div class="form_item">
        <label for="username">用户名：</label>
        <input type="text" name="username"  placeholder="请输入用户名" required />
      </div>
      <div class="form_item">
        <label for="password">密码：</label>
        <input type="password" name="password" placeholder="请输入密码名" required/>
      </div>
      <div class="form_item">
        <label for="email">电子邮箱：</label>
        <input type="email" name="email" id="email" placeholder="请输入电子邮件" required>
      </div>
      <div class="form_item">
        <label for="tel">电话：</label>
        <input type="tel" name="tel" id="tel" placeholder="请输入手机号码" required>
      </div>
      <div class="form_item">
        <input type="submit" value="注册">
      </div>
    </form>
    <div class="info">已有账号？点击<span class="switch login_Btn">登录</span></div>
    </div>
  </div>
</body>
</html>

二、实现查看 修改
在这里插入图片描述

<%--
  Created by IntelliJ IDEA.
  User: love
  Date: 2020/3/15
  Time: 16:40
  To change this template use File | Settings | File Templates.
--%>
<%--
  Created by IntelliJ IDEA.
  User: love
  Date: 2020/3/6
  Time: 8:24
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <meta name="viewport" content="width=device-width, initial-scale=1.0">
    <meta http-equiv="X-UA-Compatible" content="ie=edge">
    <title>Document</title>

    <link rel="stylesheet" href="css/style.css">

    <script src="js/form.js"></script>

</head>
<body>

<div class="form" style="position:relative">
    <a href="/untitled/studentServlet?anhao=edit">查询用户</a>
    <!--注册表单-->
    <div class="form_register" style="position:absolute">
        <form action="/untitled/studentServlet?anhao=edit&id=${std.id}" method="post">
            <h1>修改表单</h1>
            <div class="form_item">
                <label >用户名：</label>
                <input type="text" name="username"  value="${std.username}" />
            </div>
            <div class="form_item">
                <label >密码：</label>
                <input type="password" name="password" value="${std.password}"/>
            </div>
            <div class="form_item">
                <label for="email">电子邮箱：</label>
                <input type="email" name="email" id="email" value="${std.email}"/>
            </div>
            <div class="form_item">
                <label for="tel">电话：</label>
                <input type="tel" name="tel" id="tel" value="${std.tel}"/>
            </div>
            <div class="form_item">
                <input type="submit" value="修改">
            </div>
        </form>
        <div class="info">已有账号？点击<span class="switch login_Btn">登录</span></div>
    </div>
</div>
</body>
</html>

三、实现删除

<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<%--
  Created by IntelliJ IDEA.
  User: love
  Date: 2020/3/13
  Time: 8:47
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<style>
    table{
        border-color: red;
        border-radius: 5px;
        margin: 20px auto;
    }
    .odd{
        background-color: lightpink;
    }
    .even{
        background-color: goldenrod;
    }

</style>
<body>
<table border="1" cellpadding="0" cellspacing="0" width="680px">
    <tr>
        <th>编号</th>
        <th>用户名</th>
        <th>密码</th>
        <th>邮箱</th>
        <th>电话</th>
        <th>操作</th>
    </tr>
    <c:forEach items="${student}" var="s" varStatus="vs">
        <tr class="${vs.index%2==0?'even':'odd'}" align="center">
            <td>${s.id}</td>
            <td>${s.username}</td>
            <td>${s.password}</td>
            <td>${s.email}</td>
            <td>${s.tel}</td>
            <td>
                <a href="/untitled/studentServlet?anhao=update&id=${s.id}">修改</a>
                <a href="JavaScript:del('${s.id}')">删除</a>
            </td>
        </tr>
    </c:forEach>

</table>
<HR/>
<c:if test="${student != null}">
    当student != null ，你能看见我吗？
</c:if>
/* student 是有内容的 则代表不等于空 因此 下面的判断不合理 内容不输出！！*/
<c:if test="${student == null}">
    当student == null ，你能看见我吗？
</c:if>
</body>
</html>
<script type="text/javascript">
    function del(id) {
        var sure = window.confirm("您确定要删除吗？");
        if (sure){
            window.location.href ="/untitled/studentServlet?anhao=delete&id="+id;
        }
        //不用写else
    }
</script>

四、不成功的代码

<%--
  Created by IntelliJ IDEA.
  User: love
  Date: 2020/3/15
  Time: 16:19
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
    <label>取值方法</label>
   <font style="color: red"> ${jiaohap}</font>
    <hr/>
</body>
</html>

五、后台代码```java
package cn.javabs.day308;

import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;
import java.util.List;

/**

  • @author love
    */
    @WebServlet( “/studentServlet”)
    public class StudentServlet extends HttpServlet {
    // 1.定义全局变量
    StudentSerice studentSerice = new StudentSerice();

    @Override
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // 2.调用doGet方法
    doGet(request, response);
    }

    @Override
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    // 1.解决乱码
    request.setCharacterEncoding(“utf-8”);
    response.setCharacterEncoding(“utf-8”);

     //  通过一个叫做 anhao 的参数找到相应的方法  equels 比较的是内容  | ==  比较的是哈希地址值
 String anhao = request.getParameter("anhao");
 if ("reg".equals(anhao)) {
     reg(request, response);
 } else if ("find".equals(anhao)) {
     find(request, response);
 } else if ("update".equals(anhao)) {
     update(request, response);
 } else if ("edit".equals(anhao)) {
     edit(request, response);
 } else if ("delete".equals(anhao)) {
     delete(request, response);
 } else {
     System.out.println("没有找到你输入的方法，请重新输入！");
 }

    }

    /**

    • 用户登录
    • @param request
    • @param response
      */
      private void reg(HttpServletRequest request, HttpServletResponse response) {
      // 2.接受网页中传递的参数
      String username = request.getParameter(“username”);
      String password = request.getParameter(“password”);
      String email = request.getParameter(“email”);
      String tel = request.getParameter(“tel”);
      // 打印出来看一看有没有接受到参数
      System.out.println(“username 的数据:”+ username+“password的数据”+password+“email的数据”+email);
      // 把五个参数传递给StudenSerice类中
      studentSerice.register(username,password,email,tel);

    }

    /**

    • 查找全部

    • @param request

    • @param response

    • @throws IOException

    • @throws ServletException
      */
      private void find(HttpServletRequest request, HttpServletResponse response) throws IOException, ServletException {

      List list = studentSerice.findAll();
      String slist = list.toString();

      response.getWriter().write(slist);
      // 设置一个记号，放在list里面
      request.setAttribute(“student”, list);
      // 去哪个页面
      request.getRequestDispatcher("/studentList.jsp").forward(request, response);
      }

    /**

    • 修改参数

    • @param request

    • @param response

    • @throws ServletException

    • @throws IOException
      */
      private void update(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      // 2.接受网页中传递的参数
      String sid = request.getParameter(“id”);
      int id = Integer.parseInt(sid);

      Student student = studentSerice.findid(id);
      if (student == null) {
      request.setAttribute(“jiaohao”, “修改失败”);
      request.getRequestDispatcher("/message.jsp").forward(request, response);
      } else {
      System.out.println(1111);
      request.setAttribute(“std”, student);
      request.getRequestDispatcher("/StudentUpdate.jsp").forward(request, response);
      }
      }

    /**

    • 修改参数
    • @param request
    • @param response
    • @throws ServletException
    • @throws IOException
      */

    private void edit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    System.out.println(111111);
    String sid = request.getParameter(“id”);
    System.out.println(sid);
    int id = Integer.parseInt(sid);
    System.out.println(564156);
    String username = request.getParameter(“username”);
    String password = request.getParameter(“password”);
    String email = request.getParameter(“email”);
    String tel = request.getParameter(“tel”);
    System.out.println(222);
    Student student = new Student(id, username, password, email, tel);
    int result = studentSerice.editStudent(student);
    System.out.println(333);
    if (result > 0) {
    System.out.println(444);
    request.setAttribute(“jiaohap”, “修改成功”);
    request.getRequestDispatcher("/message.jsp").forward(request, response);
    } else {
    request.setAttribute(“jiaohap”, “修改失败”);
    request.getRequestDispatcher("/studentUpdate.jsp").forward(request, response);
    }
    }

    /**

    • 删除用户
    • @param request
    • @param response
    • @throws ServletException
    • @throws IOException
      */
      private void delete(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
      String sid = request.getParameter(“id”);
      int id = Integer.parseInt(sid);
      int result = studentSerice.delete(id);
      if (result > 0) {
      request.setAttribute(“jiaohao”, “删除成功”);
      request.getRequestDispatcher("/message.jsp").forward(request, response);
      } else {
      request.setAttribute(“jiaohao”, “删除失败”);
      request.getRequestDispatcher("/message.jsp").forward(request, response);
      }

    }
    }


```java

```java
package cn.javabs.day308;


import java.util.List;

public class StudentSerice {
   StudentDao studentDao= new StudentDao();

    /**
     *  用户注册
     * @param username
     * @param password
     * @param email
     * @param tel
     */
    public void register(String username, String password, String email, String tel) {
        //  如果用户名称是空字符串 或者 用户是空的返回 停止运行
        if (username.equals("") || username == null){
           return;
       }if (password.equals("") || password == null){
           return;
        }if(email.equals("") || email==null){

        }if (tel.equals("") || tel==null){
           return;
        }
        studentDao.addUser(username,password,email,tel);
    }

    /**
     * 查找全部
     * @return
     */
    public List findAll() {
        List list = studentDao.findAll();
        return list;

    }

    /**
     * 通过id查找
     * @param id
     * @return
     */
    public Student findid(int id) {
      Student student =  studentDao.findId(id);
        return student;
    }

    /**
     * 修改
     * @param student
     * @return
     */
    public int editStudent(Student student) {
       int date = studentDao.editStudent(student);
          return  date;
    }

    /**
     * 删除
     * @param id
     * @return
     */
    public int delete(int id) {
        int date  = studentDao.delete(id);
        return  date;
    }
}



```java
package cn.javabs.day308;

import org.apache.commons.dbutils.QueryRunner;
import org.apache.commons.dbutils.handlers.BeanHandler;
import org.apache.commons.dbutils.handlers.BeanListHandler;

import java.sql.SQLException;
import java.util.List;

public class StudentDao {
            /**
             * 第一部分：增删改  update 更新，更改
             */
            QueryRunner qr = new QueryRunner(DbcpUtils.getDataSource());

            public void addUser(String username, String password, String email, String tel) {
                try {
                   qr.update("insert into party(username,password,email,tel) values (?,?,?,?)",username,password,email,tel);

                } catch (SQLException e) {
                    throw new RuntimeException(e);
                }
            }
        public List findAll(){
            try {
                List<Student> list = qr.query("select*from party", new BeanListHandler<Student>(Student.class));
                return list;
            } catch (SQLException e) {
                throw new RuntimeException(e);
            }

        }

    public Student findId(int id) {
        try {
            Student student = qr.query("select * from party where id=?",
                    new BeanHandler<Student>(Student.class),id);
            return student;
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }

    }

    public int editStudent(Student student) {
                try {
                    int data = qr.update("update party set username=?,password=?,email=? ,tel=? where id=?",
                            student.getUsername(),
                            student.getPassword(),
                            student.getEmail(),
                            student.getTel(),
                            student.getId());
                return data;
                }catch (SQLException e){
                    throw new RuntimeException(e);
                }
    }

    public int delete(int id) {
        try {
          int date  =  qr.update("delete from party where id=?",id);
          return date;
        } catch (SQLException e) {
            throw new RuntimeException(e);
        }
    }
}
``
package cn.javabs.day308;

import org.apache.commons.dbcp2.BasicDataSourceFactory;

import javax.sql.DataSource;
import java.io.InputStream;
import java.sql.Connection;
import java.sql.SQLException;
import java.util.Properties;

public class DbcpUtils {
    // 初始化：需要定义数据源  类
    public static DataSource dataSource;
    static {
        // 汉语翻译： 类名.class.获取类加载器.获取资源作为流("配置文件的名称"); |  propeties 是一个配置文件的类型  使用它比较方便
        InputStream in = DbcpUtils.class.getClassLoader().getResourceAsStream("jdbc.properties");
        // 实例化对象 Properties 类
        Properties p = new Properties();
        try {
            // 通过 p 对象进行加载配置文件输入流
            p.load(in);
                // 基础数据源工厂.创建数据源
            dataSource = BasicDataSourceFactory.createDataSource(p);
        } catch (Exception e) {
            throw new RuntimeException(e);
        }

    }
    // 调用我的方法，并返回这个数据
    public static DataSource getDataSource() {
        return dataSource;
    }
    // 数据源连接的方法
    public  static Connection getConnection() throws SQLException {
        return dataSource.getConnection();
    }
}

```java
package cn.javabs.day308;

public class Student {
    private  int id;
    private  String username;
    private  String password;
    private  String email;
    private  String tel;

    public Student() {
        super();
    }

    public Student(int id, String username, String password, String email, String tel) {
        this.id = id;
        this.username = username;
        this.password = password;
        this.email = email;
        this.tel = tel;
    }

    @Override
    public String toString() {
        return "Student{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                ", email='" + email + '\'' +
                ", tel='" + tel + '\'' +
                '}';
    }

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getEmail() {
        return email;
    }

    public void setEmail(String email) {
        this.email = email;
    }

    public String getTel() {
        return tel;
    }

    public void setTel(String tel) {
        this.tel = tel;
    }
}
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