Update

src/finalexam/Database/PasswordChange.java

@@ -4,22 +4,20 @@ import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.sql.SQLException;
 import java.util.Scanner;
 import java.util.regex.Matcher;
 import java.util.regex.Pattern;
 
 public class PasswordChange {
-    static final String DBURL = "jdbc:mysql://localhost:3306/xiaoshou?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT";
+    private static final String DBDRIVER = "com.mysql.cj.jdbc.Driver";
+    private static final String DBURL = "jdbc:mysql://localhost:3306/xiaoshou?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT";
 
-    public static void main(String[] args) {
-        Scanner scanner = new Scanner(System.in);
-        Connection conn = null;
+    public static void main(String[] args) throws Exception {
+        Class.forName(DBDRIVER);
+        Connection conn = DriverManager.getConnection(DBURL);
         PreparedStatement pstmt = null;
         ResultSet rs = null;
-        try {
-            Class.forName("com.mysql.cj.jdbc.Driver");
-            conn = DriverManager.getConnection(DBURL);
+        Scanner scanner = new Scanner(System.in);
         System.out.print("请输入用户名：");
         String username = scanner.nextLine();
         String checkUserSql = "SELECT xingming FROM t_yong WHERE yonghuming=?";
@@ -65,20 +63,9 @@ public class PasswordChange {
             System.out.println("您已成功修改密码，请谨记");
         else
             System.out.println("密码修改失败，请重试");
-        } catch (Exception e) {
-            e.printStackTrace();
-        } finally {
-            try {
-                if (rs != null)
         rs.close();
-                if (pstmt != null)
         pstmt.close();
-                if (conn != null)
         conn.close();
-            } catch (SQLException se) {
-                se.printStackTrace();
-            }
-        }
     }
 
     public static boolean isPasswordComplex(String password) {

src/finalexam/Database/ProductAdditionAndInquiry.java

@@ -9,12 +9,15 @@ import java.sql.SQLException;
 import java.util.Scanner;
 
 public class ProductAdditionAndInquiry {
+    private static final String DBDRIVER = "com.mysql.cj.jdbc.Driver";
     private static final String DBURL = "jdbc:mysql://localhost:3306/xiaoshou?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT";
 
-    public static void main(String[] args) {
+    public static void main(String[] args) throws Exception {
+        Class.forName(DBDRIVER);
+        Connection conn = DriverManager.getConnection(DBURL);
         Scanner scanner = new Scanner(System.in);
         int choice;
-        try (Connection conn = DriverManager.getConnection(DBURL)) {
+
         do {
             System.out.println("===超市商品管理维护====");
             System.out.println("1、输入商品");
@@ -37,9 +40,7 @@ public class ProductAdditionAndInquiry {
                     System.out.println("无效选择，请重新选择（1-3）：");
             }
         } while (choice != 3);
-        } catch (SQLException e) {
-            e.printStackTrace();
-        }
+        conn.close();
     }
 
     private static void addProduct(Scanner scanner, Connection conn) throws SQLException {

src/finalexam/Database/UserLogin.java

@@ -4,22 +4,20 @@ import java.sql.Connection;
 import java.sql.DriverManager;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
-import java.sql.SQLException;
 import java.text.SimpleDateFormat;
 import java.util.Date;
 import java.util.Scanner;
 
 public class UserLogin {
-    static final String DBURL = "jdbc:mysql://localhost:3306/xiaoshou?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT";
+    private static final String DBDRIVER = "com.mysql.cj.jdbc.Driver";
+    private static final String DBURL = "jdbc:mysql://localhost:3306/xiaoshou?useUnicode=true&characterEncoding=utf-8&useSSL=false&serverTimezone=GMT";
 
-    public static void main(String[] args) {
-        Scanner scanner = new Scanner(System.in);
-        Connection conn = null;
+    public static void main(String[] args) throws Exception {
+        Class.forName(DBDRIVER);
+        Connection conn = DriverManager.getConnection(DBURL);
         PreparedStatement pstmt = null;
         ResultSet rs = null;
-        try {
-            Class.forName("com.mysql.cj.jdbc.Driver");
-            conn = DriverManager.getConnection(DBURL);
+        Scanner scanner = new Scanner(System.in);
         int attempts = 0;
         boolean loginSuccess = false;
         while (attempts < 3 && !loginSuccess) {
@@ -48,19 +46,8 @@ public class UserLogin {
         }
         if (!loginSuccess)
             System.out.println("最多只能尝试3次");
-        } catch (Exception e) {
-            e.printStackTrace();
-        } finally {
-            try {
-                if (rs != null)
         rs.close();
-                if (pstmt != null)
         pstmt.close();
-                if (conn != null)
         conn.close();
-            } catch (SQLException se) {
-                se.printStackTrace();
-            }
-        }
     }
 }