diff --git "a/36 \350\265\265\345\220\257\346\201\222/20223.5.21.txt" "b/36 \350\265\265\345\220\257\346\201\222/20223.5.21.txt"
new file mode 100644
index 0000000000000000000000000000000000000000..e04b6ec2ae510d1a1c30baac43ebe02eab288955
--- /dev/null
+++ "b/36 \350\265\265\345\220\257\346\201\222/20223.5.21.txt"	
@@ -0,0 +1,182 @@
+try {
+               Class.forName("com.mysql.jdbc.Driver");
+               String url = "jdbc:mysql://localhost:3306/text?useSSL=false&useUnicode=true&characterEncoding=utf8";
+               String username = "root";
+               String password = "root";
+               Connection conn = DriverManager.getConnection(url,username,password);
+               String sql = "select * from student";
+               Statement st = conn.createStatement();
+               ResultSet re = st.executeQuery(sql);
+               System.out.println("编号\t\t姓名\t\t性别");
+               while (re.next()) {
+                   int id = re.getInt(1);
+                   String name = re.getString(2);
+                   String sex = re.getString(3);
+                   System.out.println(id+"\t\t"+name+"\t\t"+sex);
+               }
+               re.close();
+               st.close();
+               conn.close();
+           } catch (ClassNotFoundException e) {
+               throw new RuntimeException(e);
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+   ```
+
+   添加功能
+
+   ```java
+   try {
+               Class.forName("com.mysql.jdbc.Driver");
+               String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+               String username = "root";
+               String password = "root";
+               Connection conn = DriverManager.getConnection(url,username,password);
+               String sql = "insert into student values(4,'A','男')";
+               Statement st = conn.createStatement();
+               int i = st.executeUpdate(sql);
+               System.out.println("添加了"+i+"行");
+               st.close();
+               conn.close();
+           } catch (ClassNotFoundException e) {
+               throw new RuntimeException(e);
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+   ```
+
+   修改功能
+
+   ```java
+   try {
+               Class.forName("com.mysql.jdbc.Driver");
+               String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+               String username = "root";
+               String password = "root";
+               Connection conn = DriverManager.getConnection(url,username,password);
+               String sql = "update student set name = 'B' where name = 'A'";
+               Statement st = conn.createStatement();
+               int i = st.executeUpdate(sql);
+               System.out.println("修改了"+i+"行");
+               st.close();
+               conn.close();
+           } catch (ClassNotFoundException e) {
+               throw new RuntimeException(e);
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+   ```
+
+   删除功能
+
+   ```java
+   try {
+               Class.forName("com.mysql.jdbc.Driver");
+               String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+               String username = "root";
+               String password = "root";
+               Connection conn = DriverManager.getConnection(url,username,password);
+               String sql = "delete from student where id = 1";
+               Statement st = conn.createStatement();
+               int i = st.executeUpdate(sql);
+               System.out.println("删除了"+i+"行");
+               st.close();
+               conn.close();
+           } catch (ClassNotFoundException e) {
+               throw new RuntimeException(e);
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+
+6. 扩展题【预习题】
+
+   1. 能否实现一个类中，用四个方法来实现上面4个类的功能
+   2. 能否实现将查询的结果，封装成java对象
+   
+   ```java
+   import java.sql.*;
+   
+   public class Jdbc {
+   
+       //注册+连接
+       Connection conn() {
+           try {
+               Class.forName("com.mysql.jdbc.Driver");
+               String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&characterEncoding=utf8";
+               String username = "root";
+               String password = "root";
+               Connection conn = DriverManager.getConnection(url, username, password);
+               Statement st = conn.createStatement();
+               return conn;
+           } catch (ClassNotFoundException e) {
+               throw new RuntimeException(e);
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+       }
+   
+       //添加
+       void add(String sql){
+           Connection conn = conn();
+           try {
+               Statement st = conn.createStatement();
+               int i = st.executeUpdate(sql);
+               System.out.println("添加了"+i+"行");
+               st.close();
+               conn.close();
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+       }
+   
+       //删除
+       void delete(String sql){
+           Connection conn = conn();
+           try {
+               Statement st = conn.createStatement();
+               int i = st.executeUpdate(sql);
+               System.out.println("删除了"+i+"行");
+               st.close();
+               conn.close();
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+       }
+   
+       //修改
+       void update(String sql){
+           Connection conn = conn();
+           try {
+               Statement st = conn.createStatement();
+               int i = st.executeUpdate(sql);
+               System.out.println("修改了"+i+"行");
+               st.close();
+               conn.close();
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+       }
+   
+       //查询
+       void select(String sql){
+           Connection conn = conn();
+           try {
+               Statement st = conn.createStatement();
+               ResultSet re = st.executeQuery(sql);
+               System.out.println("编号\t\t姓名\t\t性别");
+               while (re.next()) {
+                   int id = re.getInt(1);
+                   String name = re.getString(2);
+                   String sex = re.getString(3);
+                   System.out.println(id+"\t\t"+name+"\t\t"+sex);
+               }
+               re.close();
+               st.close();
+               conn.close();
+           } catch (SQLException e) {
+               throw new RuntimeException(e);
+           }
+       }
+   
+   }
\ No newline at end of file
diff --git "a/36 \350\265\265\345\220\257\346\201\222/2023.5.20.txt" "b/36 \350\265\265\345\220\257\346\201\222/2023.5.20.txt"
new file mode 100644
index 0000000000000000000000000000000000000000..ae85ade2aaf4d6ffccc2b0b8660d60ff91587447
--- /dev/null
+++ "b/36 \350\265\265\345\220\257\346\201\222/2023.5.20.txt"	
@@ -0,0 +1,90 @@
+ResultSet re = null;
+        try {
+            //1 加载MySQL驱动类
+            Class.forName("com.mysql.cj.jdbc.Driver");
+            //2 创建Mysql连接
+            String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false";
+            Connection conn = DriverManager.getConnection(url, "root", "200311");
+            //3 创建sql语句对象
+            String sql = "select * from student";
+            //4 创建执行sqk语句的对象
+            Statement st = conn.createStatement();
+            //5 执行sql语句
+            re = st.executeQuery(sql);
+            //6 执行返回结果
+            while (re.next()) {
+                stu stu = new stu();
+                stu.setId(re.getInt(1));
+                stu.setName(re.getString(2));
+                stu.setSex(re.getString(3));
+                list.add(stu);
+            }
+        } catch (ClassNotFoundException e) {
+            System.out.println("驱动包异常");
+            e.printStackTrace();
+        } catch (SQLException e) {
+            System.out.println("sql语句异常");
+            e.printStackTrace();
+        }
+
+
+添加
+try {
+            Class.forName("com.mysql.cj.jdbc.Driver");
+            String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false";
+            Connection conn = DriverManager.getConnection(url, "root", "200311");
+            Statement st = conn.createStatement();
+            int i = st.executeUpdate("insert into student values (4,'王四','女')");
+            if (i > 0) {
+                System.out.println("添加成功");
+            } else {
+                System.out.println("添加失败");
+            }
+        } catch (ClassNotFoundException e) {
+            System.out.println("驱动包异常");
+            e.printStackTrace();
+        } catch (SQLException e) {
+            System.out.println("sql语句异常");
+            e.printStackTrace();
+        }
+
+修改
+try {
+            Class.forName("com.mysql.cj.jdbc.Driver");
+            String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false";
+            Connection conn = DriverManager.getConnection(url, "root", "200311");
+            Statement st = conn.createStatement();
+            int i = st.executeUpdate("update student set name='四四' where id=2");
+            if (i > 0) {
+                System.out.println("修改成功");
+            } else {
+                System.out.println("修改失败");
+            }
+        } catch (ClassNotFoundException e) {
+            System.out.println("驱动包异常");
+            e.printStackTrace();
+        } catch (SQLException e) {
+            System.out.println("sql语句异常");
+            e.printStackTrace();
+        }
+
+
+删除
+try {
+            Class.forName("com.mysql.cj.jdbc.Driver");
+            String url = "jdbc:mysql://localhost:3306/student_db?useSSL=false";
+            Connection conn = DriverManager.getConnection(url, "root", "200311");
+            Statement st = conn.createStatement();
+            int i = st.executeUpdate("delete from student where id=4");
+            if (i > 0) {
+                System.out.println("删除成功");
+            } else {
+                System.out.println("删除失败");
+            }
+        } catch (ClassNotFoundException e) {
+            System.out.println("驱动包异常");
+            e.printStackTrace();
+        } catch (SQLException e) {
+            System.out.println("sql语句异常");
+            e.printStackTrace();
+        }
\ No newline at end of file