checkservlet.java

ajax验证用户输入例子

package cn.edu.bit.servlet;

import java.io.IOException;

import javax.servlet.ServletConfig;
import javax.servlet.RequestDispatcher;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;


public class CheckServlet extends HttpServlet {
	
	public String[] usernameList;
	
	public void doGet(HttpServletRequest request,HttpServletResponse response)
	  throws IOException,ServletException
	{
		String username = (String)request.getParameter("username");
		
		String password = (String)request.getParameter("password");
		
		String repassword = (String)request.getParameter("repassword");
		
		String email = (String)request.getParameter("email");
		
		if(this.IsContain(username))
		{
			request.setAttribute("error.message","您输入的用户名已经存在!");
			RequestDispatcher requestDispatcher = request.getRequestDispatcher("error.jsp");
			requestDispatcher.forward(request,response);	
		}else
		{
			RequestDispatcher requestDispatcher = request.getRequestDispatcher("success.jsp");
			requestDispatcher.forward(request,response);
		}
	
	}
	
	public void doPost(HttpServletRequest request,HttpServletResponse response)
	  throws IOException,ServletException
	  {
		doGet(request,response);
	  }
	
	 public void init(ServletConfig config) throws ServletException {
		 usernameList = new String[]{"Tom","Jerry","Brain"};
	 }
	 
	 public boolean IsContain(String param)
	 {
		 for(int i = 0; i <usernameList.length;i++)
		 {
			 if(usernameList[i].equals(param))
			 {
				 return true;
			 }
			 else
				 continue;
		 }
		 
		 return false;
	 }
}