本文实例为大家分享了AJAX实现注册验证用户名的具体代码，供大家参考，具体内容如下
功能说明
当用户在注册页面输入用户名并且鼠标焦点离开输入框时，到数据表中去验证该用户名是否已经存在，如果存在提示不可用，否则，提示可用。
接口
1 2 3 | public interface UserDao { public User findName(String name);} |
接口实现类
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 | import java.sql.Connection;import java.sql.PreparedStatement;import java.sql.ResultSet;import java.sql.SQLException;public class UserDaoImpl implements UserDao { @Override public User findName(String name) { User user =null; Connection conn = DBHelper.getConn(); String sql = "select * from user where name=?"; try { PreparedStatement ps = conn.prepareStatement(sql); ps.setString(1,name); ResultSet rs = ps.executeQuery(); if (rs.next()){ user = new User(); user.setId(rs.getInt(1)); user.setName(rs.getString(2)); user.setPassword(rs.getString(3)); } } catch (SQLException e) { e.printStackTrace(); } return user; }} |
servlet
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 | 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 java.io.IOException;@WebServlet("/findName")public class FindNameServlet extends HttpServlet { protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { request.setCharacterEncoding("utf-8"); response.setContentType("text/html;charset=utf-8"); String name = request.getParameter("name"); UserDao userDao = new UserDaoImpl(); User name1 = userDao.findName(name); if (name1!=null){ response.getWriter().write("1"); }else { response.getWriter().write("2"); } } protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { this.doPost(request, response); }} |
JSP页面
1 2 | <title>AJAX实际操作注册验证用户名</title><script src="js/jquery-1.8.3.js"></script> |
数据库如下：
运行结果如下：
以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持IT俱乐部。
