Java中的JDBC_part1

Posted 2020-08-08

简介

JAVA程序想要对数据库进行访问，需要有JDBC驱动程序的支持。JDBC驱动程序提供了对各种主流数据库的接口，程序员只需要学习掌握这一套接口，就可以实现对所有数据库的访问代码编写。

一般步骤

1. JAVA访问数据库一般分为以下步骤
2. 加载JDBC驱动程序
3. 创建对数据库的连接
4. 执行SQL语句
5. 获取执行结果并对其处理
6. 关闭连接资源

示例代码:

import java.sql.Connection; import java.sql.DriverManager; import java.sql.ResultSet; import java.sql.SQLException; import java.sql.Statement;     public class Hello {        static final String JDBC_DRIVER = "com.mysql.jdbc.Driver";        static final String DB_URL = "jdbc:mysql://localhost:3306/mldn";        static final String USERNAME = "root";        static final String PASSWORD = "admin";            public static void main(String a[])      {        Connection conn = null;        Statement stmt = null;        ResultSet rs = null;        try               {               //加载驱动                      Class.forName(JDBC_DRIVER);                      //获取链接                      conn = DriverManager.getConnection(DB_URL, USERNAME, PASSWORD);                      //执行SQL语句                      stmt = conn.createStatement();                      rs = stmt.executeQuery("SELECT name FROM user;");                      //获取结果                      while(rs.next())                      {                            System.out.println("Hello " + rs.getString("name"));                      }               }        //异常处理        catch (ClassNotFoundException e)               {                      // TODO Auto-generated catch block                      e.printStackTrace();               } catch (SQLException e)               {                      // TODO Auto-generated catch block                      e.printStackTrace();               }        finally        {               //资源清理                      try                      {                            conn.close();                            stmt.close();                            rs.close();                      }                      catch(Exception e)                      {                            //ignore exceptions when closing.                      }               }            }  }