用java实现DDL数据库操作

package cn.itcast.jdbc;

import java.sql.*;

/**

• 执行DDL语句
  */
  public class JDBCDemo7 {
  public static void main(String[] args) {
  Connection conn = null;
  Statement stmt = null;
  ResultSet rs = null;
  try {
  //1. 注册驱动
  Class.forName(“com.mysql.jdbc.Driver”);
  //2.获取连接对象
  conn = DriverManager.getConnection(“jdbc:mysql:///db3”, “root”, “root”);
  //3.定义sql
  String sql = “select * from account”;
  //4.获取执行sql对象
  stmt = conn.createStatement();
  //5.执行sql
  rs = stmt.executeQuery(sql);
  //6.处理结果
  //循环判断游标是否是最后一行末尾。
  while(rs.next()){

           //获取数据
           //6.2 获取数据
           int id = rs.getInt(1);
           String name = rs.getString("name");
           double balance = rs.getDouble(3);
  
           System.out.println(id + "---" + name + "---" + balance);
       }
  
  
      /* //6.1 让游标向下移动一行
       if(rs.next()){
           //判断是否有数据
           //6.2 获取数据
           int id = rs.getInt(1);
           String name = rs.getString("name");
           double balance = rs.getDouble(3);
  
           System.out.println(id + "---" + name + "---" + balance);
       }
  
       //6.1 让游标向下移动一行
       if(rs.next()){
           //判断是否有数据
           //6.2 获取数据
           int id = rs.getInt(1);
           String name = rs.getString("name");
           double balance = rs.getDouble(3);
  
           System.out.println(id + "---" + name + "---" + balance);
       }
  
       //6.1 让游标向下移动一行
       if(rs.next()){
           //判断是否有数据
           //6.2 获取数据
           int id = rs.getInt(1);
           String name = rs.getString("name");
           double balance = rs.getDouble(3);
  
           System.out.println(id + "---" + name + "---" + balance);
       }
  
       //6.1 让游标向下移动一行
       if(rs.next()){
           //判断是否有数据
           //6.2 获取数据
           int id = rs.getInt(1);
           String name = rs.getString("name");
           double balance = rs.getDouble(3);
  
           System.out.println(id + "---" + name + "---" + balance);
       }*/
  
     /*  //6.1 让游标向下移动一行
       rs.next();
       //6.2 获取数据
       int id2 = rs.getInt(1);
       String name2 = rs.getString("name");
       double balance2 = rs.getDouble(3);
  
       System.out.println(id2 + "---" + name2 + "---" + balance2);
  
       //6.1 让游标向下移动一行
       rs.next();
       //6.2 获取数据
       int id3 = rs.getInt(1);
       String name3 = rs.getString("name");
       double balance3 = rs.getDouble(3);
  
       System.out.println(id3 + "---" + name3 + "---" + balance3);*/
  
  
   } catch (ClassNotFoundException e) {
       e.printStackTrace();
   } catch (SQLException e) {
       e.printStackTrace();
   } finally {
       //7.释放资源
  
       if(rs != null){
           try {
               rs.close();
           } catch (SQLException e) {
               e.printStackTrace();
           }
       }
  
       if(stmt != null){
           try {
               stmt.close();
           } catch (SQLException e) {
               e.printStackTrace();
           }
       }
  
       if(conn != null){
           try {
               conn.close();
           } catch (SQLException e) {
               e.printStackTrace();
           }
       }
   }
  

  }

}