JDBC连接MySQL并且查询操作。

package com.imooc.db;


import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;



public class DBUtil {
    private static final String URL="jdbc:mysql://127.0.0.1:3306/test";
    private static final String USER="root";
    private static final String PASSWORD="****";
    public static void main(String[] args)throws Exception{

    //1.加载驱动程序
    Class.forName("com.mysql.jdbc.Driver");
    //2.获得数据库的连接
    Connection conn=DriverManager.getConnection(URL, USER, PASSWORD);
    
    Statement stmt = conn.createStatement();
    ResultSet rs= stmt.executeQuery("select * from tb3");
    float sum=0;
    while(rs.next())
    {
        sum +=rs.getFloat("salary");
        System.out.println(rs.getString("username"));
    }
    System.out.println(sum);
    
    
}
}