From f678a41d8e000365fd483cb2a586b46b488af072 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E9=83=91=E7=8E=AE=E9=94=8B?= <295357613@qq.com>
Date: Sun, 28 May 2023 22:27:24 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BD=9C=E4=B8=9A?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
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---
 ...50\345\215\225\344\277\256\346\224\271.md" | 275 ++++++++++++++++++
 1 file changed, 275 insertions(+)
 create mode 100644 "17\351\203\221\347\216\256\351\224\213/20230527\350\241\250\345\215\225\344\277\256\346\224\271.md"

diff --git "a/17\351\203\221\347\216\256\351\224\213/20230527\350\241\250\345\215\225\344\277\256\346\224\271.md" "b/17\351\203\221\347\216\256\351\224\213/20230527\350\241\250\345\215\225\344\277\256\346\224\271.md"
new file mode 100644
index 0000000..85b4a6e
--- /dev/null
+++ "b/17\351\203\221\347\216\256\351\224\213/20230527\350\241\250\345\215\225\344\277\256\346\224\271.md"
@@ -0,0 +1,275 @@
+DBUtil
+
+```java
+package utils;
+import java.sql.*;
+
+/**
+ * 工具类
+ */
+public class DBUtil {
+    //1.设置主机，端口号，数据库，关闭ssl，启用unicode和utf8，用户名，密码
+    private static final String url="jdbc:mysql:///aa?useSSL=false&useUnicode=true&characterEncoding=utf8";
+    private static final String name="root";
+    private static final String pwd="root";
+    static {
+        try {
+            Class.forName("com.mysql.jdbc.Driver");
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        }
+    }
+    public static Connection getConn() throws SQLException{
+        Connection conn = DriverManager.getConnection(url, name, pwd);
+        return conn;
+    }
+    public static ResultSet query(String sql,String...keys)throws SQLException{
+        Connection conn = getConn();
+        PreparedStatement pst = conn.prepareStatement(sql);
+        for (int i = 0; i < keys.length ; i++) {
+            pst.setString((i+1),keys[i]);
+        }
+        ResultSet rst = pst.executeQuery();
+        return rst;
+    }
+
+    //通用update
+    public static int update(String sql,String...keys)throws SQLException{
+        Connection conn = getConn();
+        PreparedStatement pst = conn.prepareStatement(sql);
+        for (int i = 0; i < keys.length; i++) {
+            pst.setString((i+1),keys[i]);
+        }
+        int i = pst.executeUpdate();
+        return i;
+    }
+
+}
+```
+
+deleteById
+
+```java
+package servlet;
+/**
+ * 删除按钮
+ */
+
+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 {
+        request.setCharacterEncoding("utf-8");
+        response.setContentType("text/html;charset=utf-8");
+        String id = request.getParameter("id");
+        String sql = "delete from student 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("删除失败");
+            }
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+    }
+}
+```
+
+saveUpdate
+
+```java
+package servlet;
+
+import utils.DBUtil;
+
+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.sql.SQLException;
+
+/**
+ * 修改按钮
+ */
+public class saveUpdate extends HttpServlet {
+    @Override
+    protected void doGet(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        doPost(req, resp);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {
+        super.doPost(req, resp);
+        req.setCharacterEncoding("utf-8");
+        resp.setContentType("text/html;charset=utf-8");
+
+        String id=req.getParameter("id");
+        String name=req.getParameter("name");
+        String sex=req.getParameter("sex");
+
+        String sql="updete student set name=?,sex=?,sex=? where id=?";
+
+        int i = 0;
+        try {
+            i = DBUtil.update(sql, id, name, sex);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+        if (i>0){
+            resp.getWriter().write("<script>alert('删除成功！');location.href='index.jsp';</script>");
+
+        }else {
+            resp.getWriter().write("删除失败");
+        }
+    }
+}
+```
+
+updateById
+
+```java
+package servlet;
+
+import bean.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 {
+        request.setCharacterEncoding("utf-8");
+        response.setContentType("text/html;charset=utf-8");
+        String id = request.getParameter("id");
+
+
+        String sql="select * from student where id=?";
+        try {
+            ResultSet rs = DBUtil.query(sql, id);
+            rs.next();
+            int id2 = rs.getInt("id");
+            String name= rs.getString("name");
+            String sex=rs.getString("sex");
+            Student stu = new Student(id2, name, sex);
+
+            request.setAttribute("student",stu);
+
+            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="java.sql.ResultSet" %>
+<%@ page import="utils.DBUtil" %><%--
+  Created by IntelliJ IDEA.
+  User: 锋垒8
+  Date: 2023/5/28
+  Time: 21:37
+  To change this template use File | Settings | File Templates.
+--%>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+<head>
+  <title>学生列表</title>
+  <style>
+    table{
+      border-collapse: collapse;
+      text-align: center;
+    }
+  </style>
+</head>
+<body>
+<table border="1" width="500">
+  <tr>
+    <th>编号</th>
+    <th>姓名</th>
+    <th>性别</th>
+    <th>操作</th>
+  </tr>
+  <%
+    String sql = "select * from student";
+    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>
+```
+
+```jsp
+<%@ page import="bean.Student" %><%--
+  Created by IntelliJ IDEA.
+  User: 锋垒8
+  Date: 2023/5/28
+  Time: 21:37
+  To change this template use File | Settings | File Templates.
+--%>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+<head>
+  <title>修改学生信息</title>
+</head>
+<body>
+<%
+  Student student = (Student) request.getAttribute("student");
+%>
+
+<%=student.getId()%>
+<%=student.getName()%>
+<%=student.getSex()%>
+
+<form action="/saveUpdate">
+  编号：<input type="text" name="id"></form><br>
+姓名：<input type="text" name="id"></form><br>
+性别：<input type="text" name="id"></form><br>
+<input type="submit" value="提交修改">
+</form>
+</body>
+</html>
+```
+
-- 
Gitee