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); } } }