用Servlet+JSP实现简单的增删改查

在这里插入图片描述
增

改

user.jsp

<%@ page import="java.util.List" %>
<%@ page import="com.jin.User" %>
<%@ page import="java.util.Date" %><%--
  Created by IntelliJ IDEA.
  com.jin.User: Jin
  Date: 2020/4/2
  Time: 15:06
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
<html>
<head>
    <title>Title</title>
</head>
<body>
<table>
    <tr>
        <th>id</th>
        <th>名字</th>
        <th>分数</th>
        <th>操作</th>
    </tr>
    <c:forEach items="${list}" var="user">
        <tr>
            <td>${user.id}</td>
            <td>${user.name}</td>
            <td>${user.score}</td>
            <td>
                <a href="userservlet?method=delete&id=${user.id}">删除</a>
                <a href="userservlet?method=findById&id=${user.id}">修改</a>
                <a href="add.jsp">添加</a>
            </td>
        </tr>
    </c:forEach>

</table>
</body>
</html>

add.jsp

<%--
  Created by IntelliJ IDEA.
  User: Jin
  Date: 2020/4/2
  Time: 20:14
  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>
<form action="userservlet" method="post">
    id:<input type="text" name="id"><br/>
    名字:<input type="text" name="name"><br/>
    成绩:<input type="text" name="score"><br/>
    <input type="submit" value="提交">
</form>
</body>
</html>

update.jsp

<%--
  Created by IntelliJ IDEA.
  User: Jin
  Date: 2020/4/2
  Time: 20:14
  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>
<form action="userservlet" method="post">
    id:<input type="text" name="id" value="${user.id}" readonly><br/>
    名字:<input type="text" name="name" value="${user.name}"><br/>
    成绩:<input type="text" name="score" value="${user.score}"><br/>
    <input type="submit" value="提交">
</form>
</body>
</html>

UserServlet

import com.jin.User;

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.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

@WebServlet("/userservlet")
public class UserServlet extends HttpServlet {

    private Map<Integer, User> map = new HashMap<>();

    public UserServlet() {
        map.put(1, new User(1, "张三", 98));
        map.put(2, new User(2, "张四", 66));
        map.put(3, new User(3, "张五", 44));
    }


    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        req.setCharacterEncoding("UTF-8");
        String method = req.getParameter("method");
        if (method == null) {
            method = "save";
        }
        String idStr = req.getParameter("id");
        String name = req.getParameter("name");
        String scoreStr = req.getParameter("score");
        Integer id = Integer.parseInt(idStr);
        Integer score = Integer.parseInt(scoreStr);
        User user = new User(id, name, score);
        map.put(id, user);
        resp.sendRedirect("/web_war_exploded/userservlet");


    }


    @Override
    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        String method = req.getParameter("method");
        if (method == null) {
            method = "findall";
        }
        if (method.equals("delete")) {
            String idStr = req.getParameter("id");
            Integer id = Integer.parseInt(idStr);
            map.remove(id);
            resp.sendRedirect("/web_war_exploded/userservlet");
        } else if (method.equals("findall")) {
            req.setAttribute("list", map.values());
            req.getRequestDispatcher("user.jsp").forward(req, resp);
        } else if (method.equals("findById")) {
            String idStr = req.getParameter("id");
            Integer id = Integer.parseInt(idStr);
            User use = map.get(id);
            req.setAttribute("user", use);
            req.getRequestDispatcher("update.jsp").forward(req, resp);
        }

    }
}

用Servlet+JSP实现简单的增删改查

猜你喜欢