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使用ajax写一个用户注册小界面
步骤 创建注册界面 -->创建数据库 --> 在jsp页面进行跳转servlet界面–>servlet界面获取将jsp页面的输入的数据 -->在dao下进行check用户名信息 -->在daoimpl下进行关于用户名查找的具体的实现 -->转到servlet界面获取查找数据库里面的是否具有用户输入的数据进行反馈到jsp页面代码部分
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>Insert title here
| 用户名 | |
| 密码 | |
| 邮箱 | |
| 简介 | |
package com.dao;import java.sql.SQLException;public interface UserDao { /* 检测用户名是否存在 */ //检测 true 存在 //false 不存在 boolean checkUserName(String username) throws SQLException ;} package com.dao.impl;import java.sql.SQLException;import org.apache.commons.dbutils.QueryRunner;import org.apache.commons.dbutils.handlers.ScalarHandler;import com.dao.UserDao;import com.util.JDBCUtil;public class UserDaoImpl implements UserDao{ //查询 @Override public boolean checkUserName(String username) throws SQLException { QueryRunner runner = new QueryRunner(JDBCUtil.getDataSource()); String sql = "select count(*) from t_user where username = ?"; //返回值为Boolean值 Long result = (Long) runner.query(sql, new ScalarHandler(),username); //大于0 true 因为有值则会返回大于0 //小于等于0 false return result>0; }} package com.servlet;import java.io.IOException;import java.sql.SQLException;import javax.servlet.ServletException;import javax.servlet.annotation.WebServlet;import javax.servlet.http.HttpServlet;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import com.dao.UserDao;import com.dao.impl.UserDaoImpl;/** * Servlet implementation class DemoServlet01 */@WebServlet("/DemoServlet01")public class DemoServlet01 extends HttpServlet { private static final long serialVersionUID = 1L; /** * @see HttpServlet#HttpServlet() */ public DemoServlet01() { super(); // TODO Auto-generated constructor stub } /** * @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response) */ protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { try { request.setCharacterEncoding("utf-8"); //检测是否存在 String name = request.getParameter("name"); System.out.println("name" + name); UserDao dao = new UserDaoImpl(); //Boolean返回 boolean exist = dao.checkUserName(name); //通知页面是否有 if(exist) { //因为write 的是字符串1 response.getWriter().println(1); //存在用户名 }else { response.getWriter().println(2); //不存在 } } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } /** * @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response) */ protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { // TODO Auto-generated method stub doGet(request, response); }} 转载地址：http://edgwi.baihongyu.com/