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);
		}
		
	}
}