From 1c22e3f1243a1ef3a7593ac84532ad514a4e32e5 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=E7=8E=8B=E5=BC=BA?= <“3108497868@qq.com”>
Date: Sat, 20 May 2023 12:01:04 +0800
Subject: [PATCH] =?UTF-8?q?=E4=BD=9C=E4=B8=9A?=
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

---
 .../230517jsp\344\275\234\344\270\232.md"     | 141 ++++++++++++++++++
 1 file changed, 141 insertions(+)
 create mode 100644 "45 \347\216\213\345\274\272/230517jsp\344\275\234\344\270\232.md"

diff --git "a/45 \347\216\213\345\274\272/230517jsp\344\275\234\344\270\232.md" "b/45 \347\216\213\345\274\272/230517jsp\344\275\234\344\270\232.md"
new file mode 100644
index 0000000..4dd8850
--- /dev/null
+++ "b/45 \347\216\213\345\274\272/230517jsp\344\275\234\344\270\232.md"	
@@ -0,0 +1,141 @@
+```mysql
+1. MySQL中创建一个数据库student_db
+
+2. 库中创建student表
+
+3. 表中数据如下
+
+4. | 编号 | 姓名 | 性别 |
+   | ---- | ---- | ---- |
+   | 1    | 张三 | 男   |
+   | 2    | 李四 | 女   |
+   | 3    | 王五 | 男   |
+
+   ~~~MySQL
+   create database student_db charset utf8;
+   use Student_db;
+   create table student (id int,`name` varchar(5),sex char(2));
+   insert into student values 
+   						(1,"张三","男"),
+   						(2,"李四","女"),
+   						(3,"王五","男");
+```
+
+```java
+5. 编写java 4个类，分别实现以下功能
+
+   1. 查询功能，查询student中所有数据
+   2. 添加功能
+   3. 修改功能
+   4. 删除功能
+
+
+import java.sql.*;
+
+//        1. 查询功能，查询student中所有数据
+public class Select {
+    public static void main(String[] args) {
+        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 = "select * from student";
+            Statement st = conn.createStatement();
+            ResultSet re = st.executeQuery(sql);
+            while (re.next()) {
+                int id = re.getInt("id");
+                String name = re.getString("name");
+                String sex = re.getString("sex");
+                System.out.println(id+","+name+","+sex);
+            }
+            re.close();
+            st.close();
+            conn.close();
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
+//        2. 添加功能
+class Add {
+    public static void main(String[] args) {
+        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,'赵六','女')";
+            Statement st = conn.createStatement();
+            int i = st.executeUpdate(sql);
+            if (i >= 1) {
+                System.out.println("成功添加了"+i+"行数据");
+            }else {
+                System.out.println("添加不了一点");
+            }
+            st.close();
+            conn.close();
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
+//        3. 修改功能
+class Update {
+    public static void main(String[] args) {
+        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 id = 5 where id = 4";
+            Statement st = conn.createStatement();
+            int i = st.executeUpdate(sql);
+            if (i >= 1) {
+                System.out.println("成功修改了"+i+"行数据");
+            }else {
+                System.out.println("修改不了一点");
+            }
+            st.close();
+            conn.close();
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
+//        4. 删除功能
+class Delete {
+    public static void main(String[] args) {
+        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 =  5";
+            Statement st = conn.createStatement();
+            int i = st.executeUpdate(sql);
+            if (i >= 1) {
+                System.out.println("成功删除了"+i+"行数据");
+            }else {
+                System.out.println("删除不了一点");
+            }
+            st.close();
+            conn.close();
+        } catch (ClassNotFoundException e) {
+            throw new RuntimeException(e);
+        } catch (SQLException e) {
+            throw new RuntimeException(e);
+        }
+    }
+}
+```
-- 
Gitee