diff --git "a/41 \347\224\230\345\260\217\345\274\272/20230528.md" "b/41 \347\224\230\345\260\217\345\274\272/20230528.md"
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@@ -0,0 +1,278 @@
+```java
+package javabean;
+
+public class Student {
+    private int id;
+    private String name;
+    private String sex;
+
+    public Student() {
+    }
+
+    public Student(int id, String name, String sex) {
+        this.id = id;
+        this.name = name;
+        this.sex = sex;
+    }
+
+    @Override
+    public String toString() {
+        return "Student{" +
+                "id=" + id +
+                ", name='" + name + '\'' +
+                ", sex='" + sex + '\'' +
+                '}';
+    }
+
+    public int getId() {
+        return id;
+    }
+
+    public void setId(int id) {
+        this.id = id;
+    }
+
+    public String getName() {
+        return name;
+    }
+
+    public void setName(String name) {
+        this.name = name;
+    }
+
+    public String getSex() {
+        return sex;
+    }
+
+    public void setSex(String sex) {
+        this.sex = sex;
+    }
+}
+
+```
+
+```java
+package servlet;
+
+import utils.DBUtil;
+
+import javax.servlet.*;
+import javax.servlet.http.*;
+import javax.servlet.annotation.*;
+import java.io.IOException;
+import java.sql.SQLException;
+
+@WebServlet(name = "deleteById", value = "/deleteById")
+public class deleteById extends HttpServlet {
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        response.setContentType("text/html;charset=utf-8");
+        request.setCharacterEncoding("utf-8");
+        String id = request.getParameter("id");
+        String sql="delete from stu where id=?";
+        try {
+            int i = DBUtil.update(sql,id);
+            if (i>0){
+                response.getWriter().write("<script>alert('删除成功！');location.href='/index.jsp';</script>");
+            }else {
+                response.getWriter().write("<script>alert('删除失败！');location.href='/index.jsp';</script>");
+            }
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+    }
+}
+
+```
+
+
+
+```java
+package servlet;
+
+import utils.DBUtil;
+
+import javax.servlet.*;
+import javax.servlet.http.*;
+import javax.servlet.annotation.*;
+import java.io.IOException;
+import java.sql.SQLException;
+
+@WebServlet(name = "savaUpdate", value = "/savaUpdate")
+public class savaUpdate extends HttpServlet {
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+      doPost(request,response);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        request.setCharacterEncoding("utf-8");
+        response.setContentType("text/html;charset=utf-8");
+        String id = request.getParameter("id");
+        String name = request.getParameter("name");
+        String sex = request.getParameter("sex");
+
+        String sql="update stu set name=?,sex=? where id=?";
+
+        int i = 0;
+        try {
+            i = DBUtil.update(sql,name,sex,id);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        if (i>0){
+                response.getWriter().write("<script>alert('修改成功！');location.href='/index.jsp';</script>");
+            }else {
+                response.getWriter().write("<script>alert('修改失败！');location.href='/index.jsp';</script>");
+
+            }
+
+
+
+    }
+}
+
+```
+
+```java
+package servlet;
+
+import javabean.Student;
+import utils.DBUtil;
+
+import javax.servlet.*;
+import javax.servlet.http.*;
+import javax.servlet.annotation.*;
+import java.io.IOException;
+import java.sql.ResultSet;
+import java.sql.SQLException;
+
+@WebServlet(name = "updateById", value = "/updateById")
+public class  updateById extends HttpServlet {
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        response.setContentType("text/html;charset=utf-8");
+        request.setCharacterEncoding("utf-8");
+        String id = request.getParameter("id");
+        String sql="select * from stu where id=?";
+        try {
+            ResultSet rs = DBUtil.query(sql,id);
+            rs.next();
+            int id1 = rs.getInt("id");
+            String name = rs.getString("name");
+            String sex = rs.getString("sex");
+            Student stuu = new Student(id1, name, sex);
+            // 将stu对象，添加到request.并转发给显示的网页
+            request.setAttribute("student",stuu);
+            request.getRequestDispatcher("/edit.jsp").forward(request,response);
+
+
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+
+
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+    }
+}
+
+```
+
+```jsp
+<%@ page import="javabean.Student" %><%--
+  Created by IntelliJ IDEA.
+  User: Administrator
+  Date: 2023-05-27
+  Time: 17:11
+  To change this template use File | Settings | File Templates.
+--%>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+<head>
+    <title>修改信息</title>
+</head>
+<body>
+<%
+  Student student =(Student) request.getAttribute("student");
+%>
+
+
+
+<form action="/savaUpdate" method="post">
+
+    姓名：<input type="text" name="name" value="<%=student.getName()%>"><br>
+    性别：<input type="text" name="sex"  value="<%=student.getSex()%>"><br>
+    <input type="hidden" name="id" value="<%=student.getId()%>"><br>
+    <input type="submit" value="修改">
+
+</form>
+
+
+
+</body>
+</html>
+
+```
+
+```jsp
+<%@ page import="utils.DBUtil" %>
+<%@ page import="java.sql.ResultSet" %><%--
+  Created by IntelliJ IDEA.
+  User: Administrator
+  Date: 2023-05-27
+  Time: 15:31
+  To change this template use File | Settings | File Templates.
+--%>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+  <head>
+    <title>$Title$</title>
+    <style>
+      table{
+        border-collapse: collapse;
+        border-color: brown;
+        text-align: center;
+      }
+    </style>
+  </head>
+  <body>
+  <table border="1" width="400">
+    <tr><th>编号</th><th>姓名</th><th>性别</th><th>操作</th></tr>
+    <%
+      String sql="select * from stu";
+      ResultSet rs = DBUtil.query(sql);
+      while (rs.next()){
+        int id = rs.getInt("id");
+        String name = rs.getString("name");
+        String sex = rs.getString("sex");
+    %>
+
+        <tr>
+      <td><%=id%></td>
+      <td><%=name%></td>
+      <td><%=sex%></td>
+          <td><a href="/updateById?id=<%=id%>">修改</a> <a href="/deleteById?id=<%=id%>">删除</a></td>
+    </tr>
+    <%
+    }
+    %>
+
+
+
+
+
+  </table>
+  </body>
+</html>
+```
+