checkusername.java

整个系统采用MVC开发模式

package conn;

import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;

import bean.UserDAO;
import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

public class CheckUsername extends HttpServlet {

	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		request.setCharacterEncoding("gbk");

		String name = request.getParameter("name");

		response.setContentType("text/xml; charset=UTF-8");
		response.setHeader("Cache-Control", "no-cache");

		PrintWriter out = response.getWriter();
		UserDAO db=new UserDAO();
		try {
			ArrayList rs =(ArrayList)db.userSelect("select *from user where username='"+name+"'");
		if (rs.size()!=0) {
			out.println("<content>用户名已存在!</content>");

		} else {
			out.println("<content>用户名可用!</content>");
		}
		}catch (Exception e) {
			e.printStackTrace();
		} 
	}
		

	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		doGet(request, response);
	}

}