diff --git "a/06 \351\231\210\345\277\227\344\274\237/20230607 \344\275\234\344\270\232.md" "b/06 \351\231\210\345\277\227\344\274\237/20230607 \344\275\234\344\270\232.md"
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index 0000000000000000000000000000000000000000..944d2863b34a6542ee2fb266d1635d1e376a3771
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+++ "b/06 \351\231\210\345\277\227\344\274\237/20230607 \344\275\234\344\270\232.md"	
@@ -0,0 +1,426 @@
+ # bean
+
+```java
+package bean;
+
+public class Attence {
+    private int aid;
+    private String time;
+    private int type;
+    private int sid;
+    private String sname;
+
+    public Attence(int aid, String time, int type, int sid, String sname) {
+        this.aid = aid;
+        this.time = time;
+        this.type = type;
+        this.sid = sid;
+        this.sname = sname;
+    }
+
+    public Attence() {
+    }
+
+    public int getAid() {
+        return aid;
+    }
+
+    public void setAid(int aid) {
+        this.aid = aid;
+    }
+
+    public String getTime() {
+        return time;
+    }
+
+    public void setTime(String time) {
+        this.time = time;
+    }
+
+    public int getType() {
+        return type;
+    }
+
+    public void setType(int type) {
+        this.type = type;
+    }
+
+    public int getSid() {
+        return sid;
+    }
+
+    public void setSid(int sid) {
+        this.sid = sid;
+    }
+
+    public String getSname() {
+        return sname;
+    }
+
+    public void setSname(String sname) {
+        this.sname = sname;
+    }
+
+    @Override
+    public String toString() {
+        return "Attence{" +
+                "aid=" + aid +
+                ", time='" + time + '\'' +
+                ", type=" + type +
+                ", sid=" + sid +
+                ", sname='" + sname + '\'' +
+                '}';
+    }
+}
+
+```
+
+```java
+package bean;
+
+public class Student {
+    private int sid;
+    private String sname;
+
+    public Student() {
+    }
+
+    public Student(int sid, String sname) {
+        this.sid = sid;
+        this.sname = sname;
+    }
+
+    public int getSid() {
+        return sid;
+    }
+
+    public void setSid(int sid) {
+        this.sid = sid;
+    }
+
+    public String getSname() {
+        return sname;
+    }
+
+    public void setSname(String sname) {
+        this.sname = sname;
+    }
+
+    @Override
+    public String toString() {
+        return "Student{" +
+                "sid=" + sid +
+                ", sname='" + sname + '\'' +
+                '}';
+    }
+}
+
+```
+
+# servlet
+
+```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;
+import java.util.ArrayList;
+
+@WebServlet("/addstu")
+public class AddServlet extends HttpServlet {
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        request.setCharacterEncoding("utf-8");
+        ArrayList<Student> list = new ArrayList<>();
+        String sql = "select * from student";
+        ResultSet re = DBUtil.getquery(sql);
+        try {
+            while (re.next()){
+                int sid = re.getInt("sid");
+                String sname = re.getString("sname");
+                Student student = new Student(sid, sname);
+                list.add(student);
+            }
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        request.setAttribute("list",list);
+        request.getRequestDispatcher("/WEB-INF/add.jsp").forward(request,response);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        request.setCharacterEncoding("utf-8");
+        String sid = request.getParameter("sid");
+        String time = request.getParameter("time");
+        String dao = request.getParameter("dao");
+        System.out.println(sid+" "+time+" "+dao);
+        String sql = "insert into attence values (?,?,?,?)";
+        int i = DBUtil.getupdate(sql, null, time, dao, sid);
+        if (i>0){
+            request.setAttribute("msg","添加成功");
+            request.getRequestDispatcher("/WEB-INF/msg.jsp").forward(request,response);
+        }else{
+            request.setAttribute("msg","添加失败");
+            request.getRequestDispatcher("/WEB-INF/msg.jsp").forward(request,response);
+        }
+    }
+}
+
+```
+
+```java
+package servlet;
+
+import bean.Attence;
+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;
+import java.util.ArrayList;
+
+@WebServlet("/allstu")
+public class AllServlet extends HttpServlet {
+    @Override
+    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+        request.setCharacterEncoding("utf-8");
+        ArrayList<Attence> list = new ArrayList<>();
+        String sql = "select * from attence a,student s where a.sid=s.sid";
+        ResultSet re = DBUtil.getquery(sql);
+        try {
+            while (re.next()){
+                int aid = re.getInt("aid");
+                String time = re.getString("time");
+                int type = re.getInt("type");
+                int sid = re.getInt("sid");
+                String sname = re.getString("sname");
+                Attence attence = new Attence(aid,time,type,sid,sname);
+                list.add(attence);
+            }
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        request.setAttribute("list",list);
+        request.getRequestDispatcher("/WEB-INF/all.jsp").forward(request,response);
+    }
+
+    @Override
+    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
+
+    }
+}
+
+```
+
+# utils
+
+```java
+package utils;
+
+import java.sql.*;
+
+public class DBUtil {
+    private static final String url = "jdbc:mysql:///AttDB?useSSL=false&characterEncoding=utf8";
+    private static final String use = "root";
+    private static final String password = "root";
+    static {
+        try {
+            Class.forName("com.mysql.jdbc.Driver");
+        } catch (ClassNotFoundException e) {
+            e.printStackTrace();
+        }
+    }
+    public static Connection getconn() {
+        Connection conn = null;
+        try {
+            conn = DriverManager.getConnection(url, use, password);
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return conn;
+    }
+    public static ResultSet getquery(String sql,Object ...keys) {
+        Connection conn = getconn();
+        ResultSet re = null;
+        try {
+            PreparedStatement pre = conn.prepareStatement(sql);
+            for (int i = 0; i < keys.length; i++) {
+                pre.setObject((i + 1), keys[i]);
+            }
+            re = pre.executeQuery();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return re;
+    }
+    public static int getupdate(String sql,Object ...keys) {
+        Connection conn = getconn();
+        int num = 0;
+        try {
+            PreparedStatement pre = conn.prepareStatement(sql);
+            for (int i = 0; i < keys.length; i++) {
+                pre.setObject((i + 1), keys[i]);
+            }
+            num = pre.executeUpdate();
+        } catch (SQLException e) {
+            e.printStackTrace();
+        }
+        return num;
+    }
+}
+
+```
+
+# jsp
+
+```jsp
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+<%--
+  Created by IntelliJ IDEA.
+  User: Administrator
+  Date: 2023-06-06
+  Time: 11:38
+  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="/addstu" method="post">
+    <table border="1" cellspacing="0">
+        <h1>学生考勤系统</h1>
+        <tr>
+            <th>学生姓名</th>
+            <td>
+                <select name="sid" id="">
+                    <c:forEach items="${list}" var="a">
+                        <option value="${a.sid}">${a.sname}</option>
+                    </c:forEach>
+                </select>
+            </td>
+        </tr>
+        <tr>
+            <th>考勤时间</th>
+            <td><input type="datetime-local" name="time"></td>
+        </tr>
+        <tr>
+            <th>考勤状况</th>
+            <td>已到:<input type="radio" name="dao" value="1">
+                迟到:<input type="radio" name="dao" value="2">
+                旷课:<input type="radio" name="dao" value="3">
+            </td>
+        </tr>
+        <tr>
+            <td colspan="2"><input type="submit" value="添加"></td>
+        </tr>
+    </table>
+</form>
+</body>
+</html>
+
+```
+
+```jsp
+<%@ taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %>
+
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+<head>
+    <title>Title</title>
+</head>
+<body>
+<a href="/addstu">添加</a>
+    <table border="1"  cellspacing="0">
+        <tr>
+            <th>考勤编号</th>
+            <th>学生编号</th>
+            <th>学生姓名</th>
+            <th>出勤时间</th>
+            <th>出勤状况</th>
+        </tr>
+        <c:forEach items="${list}" var="stu">
+            <tr>
+                <td>${stu.aid}</td>
+                <td>${stu.sid}</td>
+                <td>${stu.sname}</td>
+                <td>${stu.time}</td>
+                <td>
+                    <c:if test="${stu.type==1}">
+                        已到
+                    </c:if>
+                    <c:if test="${stu.type==2}">
+                        迟到
+                    </c:if>
+                    <c:if test="${stu.type==3}">
+                        旷课
+                    </c:if>
+                </td>
+            </tr>
+        </c:forEach>
+    </table>
+</body>
+</html>
+
+```
+
+```jsp
+<%--
+  Created by IntelliJ IDEA.
+  User: Administrator
+  Date: 2023-06-06
+  Time: 20:26
+  To change this template use File | Settings | File Templates.
+--%>
+<%@ page contentType="text/html;charset=UTF-8" language="java" %>
+<html>
+<head>
+    <title>Title</title>
+</head>
+<body>
+<h1>${msg}</h1>
+</body>
+</html>
+
+```
+
+# mysql
+
+```mysql
+create database AttDB charset utf8;
+use AttDB;
+create table Student (
+  sid int primary key auto_increment,
+  sname varchar(20) not null unique
+);
+create table Attence (
+    aid int primary key auto_increment,
+    time varchar(20) not null ,
+    typr int comment '1:已到；2:迟到；3旷课',
+    sid int,
+    foreign key (sid) references Student(sid)
+);
+insert into Student values
+                        (0,"张三"),
+                        (0,"李四"),
+                        (0,"王五");
+insert into Attence values
+                        (0,"2022-05-20 08:20:00",1,1),
+                        (0,"2022-05-23 08:20:00",2,1),
+                        (0,"2022-05-23 13:40:00",2,2),
+                        (0,"2022-05-27 08:20:00",3,2),
+                        (0,"2022-05-30 08:20:00",2,3);
+```
+