From d146a3910c1859fd9a6cff0340e3365183c3cab0 Mon Sep 17 00:00:00 2001
From: xcchengguo <2395432766@qq.com>
Date: Sun, 21 May 2023 23:43:28 +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

---
 .../20230521 \344\275\234\344\270\232.md"     | 62 +++++++++++++++++++
 1 file changed, 62 insertions(+)
 create mode 100644 "18 \350\260\242\345\256\270/20230521 \344\275\234\344\270\232.md"

diff --git "a/18 \350\260\242\345\256\270/20230521 \344\275\234\344\270\232.md" "b/18 \350\260\242\345\256\270/20230521 \344\275\234\344\270\232.md"
new file mode 100644
index 0000000..49fd21a
--- /dev/null
+++ "b/18 \350\260\242\345\256\270/20230521 \344\275\234\344\270\232.md"	
@@ -0,0 +1,62 @@
+~~~java
+import java.sql.*;
+import java.util.ArrayList;
+
+public class Gongju {
+    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("jdbc:mysql://localhost:3306/student_db?useSSL=false&useUnicode=true&character=utf8", "root", "root");
+        return conn;
+    }
+    public static ResultSet Query(String sql,String ...keys) throws SQLException {
+        Connection conn = getConn();
+        PreparedStatement pre = conn.prepareStatement(sql);
+        for (int i = 0; i < keys.length; i++) {
+//            pre.setString((i+1),keys[i]);
+            pre.setString((i+1),keys[i]);
+        }
+        ResultSet res = pre.executeQuery();
+        return res;
+    }
+    public static void close(Connection con,PreparedStatement pre,ResultSet res) throws SQLException {
+        if(res!=null){
+            res.close();
+        }if(pre!=null){
+            pre.close();
+        }if(con!=null){
+            con.close();
+        }
+    }
+}
+~~~
+
+~~~java
+import java.sql.ResultSet;
+import java.sql.SQLException;
+import java.util.ArrayList;
+
+public class Testi {
+    static class test{
+        public static void main(String[] args) throws SQLException {
+            String sql="select * from student";
+            ResultSet res = Gongju.Query(sql);
+            ArrayList<Studenti> list = new ArrayList<>();
+            while (res.next()){
+                list.add(new Studenti(res.getString(1),res.getString(2),res.getString(3)));
+            }
+            for (int i = 0; i < list.size(); i++) {
+                Studenti student = list.get(i);
+                System.out.println(student);
+            }
+            Gongju.close(null,null,res);
+        }
+    }
+}
+~~~
+
-- 
Gitee