checkusernameservlet.java

java编程新手学习ajax时候可以参考此文档

package com.jisong.ajax;

import java.io.IOException;
import java.io.PrintWriter;
import java.net.URLDecoder;

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

public class CheckUserNameServlet extends HttpServlet {

	/**
	 * Constructor of the object.
	 */
	public CheckUserNameServlet() {
		super();
	}

	/**
	 * Destruction of the servlet. <br>
	 */
	public void destroy() {
		super.destroy(); // Just puts "destroy" string in log
		// Put your code here
	}

	/**
	 * The doGet method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to get.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		//1.取得参数值
		request.setCharacterEncoding("UTF-8");
		
		String user=request.getParameter("username");
//		user=URLDecoder.decode(user);
//		user=new String(user.getBytes(),"UTF-8");
		
		System.out.println("取得用户名："+user);
		//2.进行检查
		boolean flag=false;
		if(user!=null && user.equals("accp")){
			flag=true;//该用户已经存在
		}else
			flag=false;
		//3.输出结果
		response.setContentType("text/html;charset=UTF-8");
		PrintWriter out = response.getWriter();
		out.print(flag);
		out.close();
	}

	/**
	 * The doPost method of the servlet. <br>
	 *
	 * This method is called when a form has its tag value method equals to post.
	 * 
	 * @param request the request send by the client to the server
	 * @param response the response send by the server to the client
	 * @throws ServletException if an error occurred
	 * @throws IOException if an error occurred
	 */
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		System.out.println("************调用了doPost");
		doGet(request,response);
	}

	/**
	 * Initialization of the servlet. <br>
	 *
	 * @throws ServletException if an error occurs
	 */
	public void init() throws ServletException {
		// Put your code here
	}

}