userservlet.java

出学者的基础,你可以用它来开始你学习AJAX的旅程.很简单的.

package demo;

import javax.servlet.*;
import javax.servlet.http.*;

import java.io.*;

public class UserServlet extends HttpServlet{
	public void service(HttpServletRequest req,HttpServletResponse res)throws IOException,ServletException{
		//处理验证用户唯一性的请求，真正处理业务逻辑的是model
		//因此这里需要model的实例
		res.setContentType("text/html;charset=gb2312");
		req.setCharacterEncoding("gb2312");

		//得到用户请求的方法
		String method = req.getParameter("method");
		if(method.equals("checkUser")){//检查用户是否已经存在
			checkUser(req,res);
		}else if(method.equals("validateUser")){//检查用户的合法性
			validateUser(req,res);
		}
	}

	//验证用户的唯一性
	public void checkUser(HttpServletRequest req,HttpServletResponse res)throws IOException{
		PrintWriter out = res.getWriter();
		if(getUserModel().validateUser(req.getParameter("username"))){
			out.print("true");
			out.close();
		}else{
			out.print("false");
			out.close();
		}
	}

	//验证用户的合法性
	public void validateUser(HttpServletRequest req,HttpServletResponse res)throws IOException{
		PrintWriter out = res.getWriter();
		if(getUserModel().validateUser(req.getParameter("username"),req.getParameter("password"))){
			out.print("true");
			out.close();
		}else{
			out.print("false");
			out.close();
		}
	}

	public UserModelIf getUserModel(){
		MyBeanFactory factory = MyBeanFactory.getInstance();
		return (UserModelIf)factory.getBean("usermodel");
	}
}