receivemailservlet.java

运用JSP/servlet/JavaBean 技术

package com.lovo.controller;

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

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

import com.lovo.po.Mail;
import com.lovo.po.MailVo;
import com.lovo.service.IMailBo;
import com.lovo.service.IMailBoImpl;

public class ReceiveMailServlet extends HttpServlet
{
	/** mailBo接口，用于业务方法调用 */
	private IMailBo mailBo = new IMailBoImpl();

	/**
	 * 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
	{
		/** 设置响应文件类型及字符集编码 */
		response.setContentType("text/xml; charset=utf-8");
		/** 设置响应头，让浏览器不缓存信息 */
		response.setHeader("Cache-control", "no-cache");
		/** 获取请求收件的帐号userId */
		int userId = Integer.parseInt(request.getParameter("userId"));
		/** 查询未读信件 */
		List<MailVo> notReadList = mailBo.queryMail(userId, Mail.NOT_READ_MAIL);
		/** 查询已读信件 */
		List<MailVo> readYetList = mailBo.queryMail(userId, Mail.READ_YET_MAIL);
		/** 将收到的信件添加到session */
		HttpSession session = request.getSession();
		session.setAttribute("notReadList", notReadList);
		session.setAttribute("readYetList", readYetList);
		boolean create  = true;//标志是否需要构建xml
		int notReadMail = notReadList == null ? 0 : notReadList.size();//未读信件数量
		int readYetMail = readYetList == null ? 0 : readYetList.size();//已读信件数量
//		System.out.println("notReadList.size=" + notReadMail);
//		System.out.println("readYetList.size=" + readYetMail);
		/** 判断是否需要构建xml */
		if(notReadMail == 0 && readYetMail == 0)
		{
			/** 既没有未读信件，也没有已读信件则不需构建xml，将create设为false */
			create = false;
		}
		/** 无信息返回 */
		if(create == false)
		{
			return;
		}
		/** 获得输出流 */
		PrintWriter writer = response.getWriter();
		/** 构建xml */
		writer.println("<?xml version='1.0' encoding='UTF-8'?>");
		writer.println("<mail>");
		String whoSend = "";//存发件人帐号
		String mailTitle = "";//存邮件标题
		int mailId = 0;//存邮件Id
		MailVo mailVo = null;//存当前邮件
		/** 如果有未读信件那么做以下操作 */
		if(notReadMail != 0)
		{
			/**
			 * 遍历notReadList获得要返回页面的信息并构建xml
			 */
			for(int i = 0; i < notReadMail; i++)
			{
				/** 获得当前未读邮件 */
				mailVo = notReadList.get(i);
				/** 获得发件人帐号 */
				whoSend = mailVo.getWhoSendedName();
				/** 获得邮件主题 */
				mailTitle = mailVo.getMailTitle();
				/** 获得邮件ID */
				mailId = mailVo.getMailId();
				writer.println("<notreadmail>");
				writer.println("<whosend>" + whoSend + "</whosend>");
				writer.println("<mailtitle>" + mailTitle + "</mailtitle>");
				writer.println("<mailid>" + mailId + "</mailid>");
				writer.println("</notreadmail>");
			}
		}
		/** 如果有已读信件那么做以下操作 */
		if(readYetMail != 0)
		{
			/**
			 * 遍历readYetList获得要返回页面的信息并构建xml
			 */
			for(int i = 0; i < readYetMail; i++)
			{
				/** 获得当前已读邮件 */
				mailVo = readYetList.get(i);
				/** 获得发件人帐号 */
				whoSend = mailVo.getWhoSendedName();
				/** 获得邮件主题 */
				mailTitle = mailVo.getMailTitle();
				/** 获得邮件ID */
				mailId = mailVo.getMailId();
				writer.println("<readyetmail>");
				writer.println("<whosend>" + whoSend + "</whosend>");
				writer.println("<mailtitle>" + mailTitle + "</mailtitle>");
				writer.println("<mailid>" + mailId + "</mailid>");
				writer.println("</readyetmail>");
			}
		}
		writer.println("</mail>");
		writer.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
	{
		doGet(request, response);
	}

}