JDBC connects MySQL and queries the operation.

1  Packagecom.imooc.db;2 3 4 Importjava.sql.Connection;5 ImportJava.sql.DriverManager;6 ImportJava.sql.ResultSet;7 Importjava.sql.SQLException;8 Importjava.sql.Statement;9 Ten  One  A  Public classDbutil { -     Private Static FinalString url= "Jdbc:mysql://127.0.0.1:3306/test"; -     Private Static FinalString user= "Root"; the     Private Static FinalString password= "* * * *"; -      Public Static voidMain (string[] args)throwsexception{ -  -     //1. Loading drivers +Class.forName ("Com.mysql.jdbc.Driver"); -     //2. Get a connection to the database +Connection conn=drivermanager.getconnection (URL, USER, PASSWORD); A      atStatement stmt =conn.createstatement (); -ResultSet rs= stmt.executequery ("SELECT * from Tb3"); -     floatSum=0; -      while(Rs.next ()) -     { -Sum +=rs.getfloat ("salary"); inSystem.out.println (rs.getstring ("username")); -     } to System.out.println (sum); +      -      the } *}

JDBC connects MySQL and queries the operation.