JavaWeb课程复习资料（十）——修改功能

承接上文：JavaWeb课程复习资料（九）——删除功能

1、创建【UpdateByIdServlet.java】

2、创建【UpdateServlet.jsp】

3、创建【UpdateServlet.jsp】

4、执行测试

1、创建【UpdateByIdServlet.java】

代码语言：javascript复制

package com.item.servlet;

import com.item.dao.UserInfoDAO;
import com.item.daoimpl.UserInfoDAOImpl;
import com.item.pojo.UserInfo;

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;

@WebServlet("/UpdateByIdServlet")
public class UpdateByIdServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        req.setCharacterEncoding("utf-8");
        String id=req.getParameter("id");
        int i = Integer.parseInt(id);
        UserInfoDAO db=new UserInfoDAOImpl();
        UserInfo userInfo = db.SelectById(i);
        req.setAttribute("userInfo",userInfo);
        req.getRequestDispatcher("UpdateServlet.jsp").forward(req,resp);
    }

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

2、创建【UpdateServlet.jsp】

代码语言：javascript复制

<%@ page import="com.item.pojo.UserInfo" %><%--
  Created by IntelliJ IDEA.
  User: 红目香薰
  Date: 2022/2/26
  Time: 13:30
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>修改页面</title>
    <link rel="stylesheet" href="https://cdn.staticfile.org/twitter-bootstrap/3.3.7/css/bootstrap.min.css">
</head>
<body>
<form action="/UpdateServlet" method="post">
    <%
        UserInfo userInfo=(UserInfo)request.getAttribute("userInfo");
    %>
    <p>
        <input type="text" name="id" value="<%= userInfo.getId()%>" class="form-control" readonly required/>
    </p>
    <p>
        创建时间:<%= userInfo.getCreateDate()%>
    </p>
    <p>
        <input type="text" placeholder="请输入用户名" value="<%= userInfo.getUserName()%>" name="userName" class="form-control" required/>
    </p>
    <p>
        <input type="text" placeholder="请输入爱好" value="<%= userInfo.getIntroduce()%>" name="introduce" class="form-control" required/>
    </p>
    <p>
        <input type="submit" value="修改" class="btn btn-primary"/>
    </p>
</form>
</body>
</html>

3、创建【UpdateServlet.jsp】

代码语言：javascript复制

package com.item.servlet;

import com.item.dao.UserInfoDAO;
import com.item.daoimpl.UserInfoDAOImpl;
import com.item.pojo.UserInfo;

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.io.PrintWriter;

@WebServlet("/UpdateServlet")
public class UpdateServlet extends HttpServlet {
    @Override
    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
        resp.setContentType("text/html;charset=utf-8");
        req.setCharacterEncoding("utf-8");
        String id = req.getParameter("id");
        String userName = req.getParameter("userName");
        String introduce = req.getParameter("introduce");
        PrintWriter out = resp.getWriter();
        if (id == null || userName == null || introduce == null) {
            out.println("<script>alert('参数不允许为空。')</script>");
        }
        UserInfoDAO db = new UserInfoDAOImpl();
        UserInfo userInfo = db.SelectById(Integer.parseInt(id));
        userInfo.setUserName(userName);
        userInfo.setIntroduce(introduce);
        boolean isf = db.UpdateById(userInfo);
        if(isf){
            out.println("<script>alert('修改成功');window.location.href='/index.jsp';</script>");
        }else{
            out.println("<script>alert('修改失败');window.location.href='/index.jsp';</script>");
        }
    }

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

4、执行测试

测试成功。

整个Servlet完成，希望能给大家带来一定的帮助。

jsp 腾讯云测试服务 java servlet

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