checkusernameexist.java

jsp + servlete + jdbc开的管理系统

package hbu.david.cmc.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import hbu.david.cmc.http.ServletEncoding;
import hbu.david.cmc.work.*;
import hbu.david.cmc.util.*;
/**
 * Servlet implementation class for Servlet: CheckUsernameExist
 *
 */
 public class CheckUsernameExist extends javax.servlet.http.HttpServlet implements javax.servlet.Servlet {
   static final long serialVersionUID = 1L;
   
    /* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#HttpServlet()
	 */
	public CheckUsernameExist() {
		super();
	}   	
	
	/* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#doGet(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub
		doPost(request,response);
	}  	
	
	/* (non-Java-doc)
	 * @see javax.servlet.http.HttpServlet#doPost(HttpServletRequest request, HttpServletResponse response)
	 */
	protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
		// TODO Auto-generated method stub		
		ServletEncoding.setEncoding(request, response);
		String username=request.getParameter("username");
		PrintWriter out=response.getWriter();
		if(StringUtil.isStringEmpty(username)){
			out.print("对不起，这个是空数据！");
			System.out.print("1");
			out.close();
		}else{
			if(UserBean.isUsernameExist(username)){
				//存在
				out.print("对不起，该用户名已经存在！");
				System.out.print("2");
				out.close();
			}else{
				out.print("恭喜您，该用户名可以使用！");
				System.out.print("3");
				out.flush();
			}
		}
	}   	  	    
}