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


public class Test17 {

    private  Connection con;
    public static void main(String[] args) {
        
    }
 public void getStudent(Connection con,String sql){
     try{
         Statement st=con.createStatement();
         ResultSet rs=st.executeQuery(sql);
         while(rs.next()){
             String name1=rs.getString(1);
             String code1=rs.getString(2);
             String sexy1=rs.getString(3);
             String age1=rs.getString(4);
             System.out.println("\nname"+name1+"\tcode"+code1+"\tsexy"+sexy1+"\tage"+age1);
         }
         st.close();
         con.close();
     }catch(Exception e){
         System.out.println(e);
     }
 }
 public Connection getConnection(){
        String driverName = "com.microsoft.sqlserver.jdbc.SQLServerDriver";
        String dbURL = "jdbc:sqlserver://localhost:1433; DatabaseName=student"; //连接服务器和数据库sample
          String userName = "sa";  //默认用户名
          String userPwd = "123";  //密码
          Connection dbConn;

          try {
           Class.forName(driverName);
           dbConn = DriverManager.getConnection(dbURL, userName, userPwd);
           System.out.println("Connection Successful!");  //如果连接成功 控制台输出Connection Successful!
          } catch (Exception e) {
           e.printStackTrace();
          }
    return con;

 }

}

大哥你的main方法里什么都没有，怎么会运行呢