java代码实现 查询mysql接口实现

以下是 Java 代码实现查询 MySQL 数据库的示例：

import java.sql.*;

public class MySQLQueryExample {
   static final String DB_URL = "jdbc:mysql://localhost:3306/mydatabase";
   static final String USER = "username";
   static final String PASS = "password";

   public static void main(String[] args) {
      Connection conn = null;
      Statement stmt = null;
      try {
         Class.forName("com.mysql.jdbc.Driver");
         conn = DriverManager.getConnection(DB_URL,USER,PASS);
         stmt = conn.createStatement();
         String sql = "SELECT id, name, age FROM persons";
         ResultSet rs = stmt.executeQuery(sql);
         while(rs.next()){
            int id  = rs.getInt("id");
            String name = rs.getString("name");
            int age = rs.getInt("age");
            System.out.print("ID: " + id);
            System.out.print(", Name: " + name);
            System.out.println(", Age: " + age);
         }
         rs.close();
         stmt.close();
         conn.close();
      } catch(SQLException se) {
         se.printStackTrace();
      } catch(Exception e) {
         e.printStackTrace();
      } finally {
         try {
            if(stmt!=null)
               stmt.close();
         } catch(SQLException se2) {
         }
         try {
            if(conn!=null)
            conn.close();
         } catch(SQLException se) {
            se.printStackTrace();
         }
      }
   }
}

这段代码使用 JDBC API 连接 MySQL 数据库，并执行一个 SELECT 查询，然后遍历结果集并打印结果。可以根据自己的需要修改 SQL 语句和结果集的处理方式。