jdbc 连接 mysql 获取 数据集 条数

package nona;import java.io.IOException;import java.io.PrintWriter;import java.sql.Connection;import java.sql.Driver;import java.sql.DriverManager;import java.sql.ResultSet;import java.sql.SQLException;import java.sql.Statement;import javax.servlet.ServletException;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;public class LoginServlet extends HttpServlet {private int num = 0; //记录有多少条记录public void doGet(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {doPost(request, response);}public boolean login(String name, String password)  {// 连接数据库String driverName = "com.mysql.jdbc.Driver";Driver d;Connection con;Statement stmt;ResultSet results;try {d = (Driver) Class.forName(driverName).newInstance();con = DriverManager.getConnection("jdbc:mysql://localhost:3307/school","root", "root");stmt = con.createStatement();String sqlstr = "select * from user where name = '"+ name +"' and password = '"+password +"'";results = stmt.executeQuery(sqlstr); // 获取数据库结果集while(results.next()){int id = results.getInt("id");String name1 = results.getString("name");String password1 = results.getString("password");System.out.println(" " + id + " " + name +" " + password);num ++;//数据条数}            stmt.close();con.close();} catch (Exception e) {e.printStackTrace();}return true;}public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException {num = 0;String name = request.getParameter("name");String password = request.getParameter("password");System.out.println("name:"+ name +"  password: "+ password);boolean success = login(name, password);PrintWriter out = response.getWriter();if(success){out.write("login success: " +num);}else{out.write("login fail : " + num);}}}