JDBC API详解2

1 //stmt.executeUpdate 执行成功后，返回值为受影响行数，对DDL不能判断其0或1来断定是否执行成功

 1 //ResultSet 
 2 //stmt.executeQuery(sql):执行DQL语句，返回ResultSet对象
 3 
 4 
 5 //获取查询结果
 6 boolean next();//将光标移到下一行，并判断下一行是否为有效行
 7 xxx getXxx(参数);//获取数据，xxx为数据类型，如：int getInt(参数);
 8 
 9 
10 import java.sql.*;
11 //获取表中的数据，并打印
12 public class JDBCdemo {
13     public static void main(String[] args) throws Exception {
14         //1.注册驱动
15         Class.forName("com.mysql.cj.jdbc.Driver");
16 
17         //2.获取连接
18         String url = "jdbc:mysql://127.0.0.1:3306/db1";
19         String username = "root";
20         String password = "1234";
21         Connection conn = DriverManager.getConnection(url,username,password);
22 
23         //定义sql
24         String sql = "select * from account";
25 
26         //获取statement对象
27         Statement statement = conn.createStatement();
28 
29         //执行sql
30         ResultSet rs = statement.executeQuery(sql);
31 
32         //处理结果
33         while(rs.next()){
34             int id = rs.getInt(1);
35             String name = rs.getString(2);
36             double money = rs.getDouble(3);
37             System.out.println(id);
38             System.out.println(name);
39             System.out.println(money);
40             System.out.println("===========================");
41         }
42 
43         //释放资源
44         rs.close();
45         statement.close();
46         conn.close();
47 
48     }
49 
50 }