JDBC连接MySQL并且查询操作。

 1 package com.imooc.db;
 2
 3
 4 import java.sql.Connection;
 5 import java.sql.DriverManager;
 6 import java.sql.ResultSet;
 7 import java.sql.SQLException;
 8 import java.sql.Statement;
 9
10
11
12 public class DBUtil {
13     private static final String URL="jdbc:mysql://127.0.0.1:3306/test";
14     private static final String USER="root";
15     private static final String PASSWORD="****";
16     public static void main(String[] args)throws Exception{
17
18     //1.加载驱动程序
19     Class.forName("com.mysql.jdbc.Driver");
20     //2.获得数据库的连接
21     Connection conn=DriverManager.getConnection(URL, USER, PASSWORD);
22
23     Statement stmt = conn.createStatement();
24     ResultSet rs= stmt.executeQuery("select * from tb3");
25     float sum=0;
26     while(rs.next())
27     {
28         sum +=rs.getFloat("salary");
29         System.out.println(rs.getString("username"));
30     }
31     System.out.println(sum);
32
33
34 }
35 }