JAVA与WEB2.0亲密接触

import java.util.Collection;
import java.util.Date;

/**
* 接口
* @author blurxx
*/
public interface Depot {
    public abstract Collection getFiles();
    public abstract Date getLastUpdateDate();
    public abstract void update();
}

/**
* Depot of files avialable in reverse chronological order.
* @author Dave Johnson
*/
public class FileDepot implements Depot {
    private String path;
    private ArrayList files = new ArrayList();
    private Date lastModified = null;
    
    /** Create file depot in existing directory */
    public FileDepot(String path) {
        this.path = path;
        update();
    }
    public synchronized void update()
    {
        File depotDir = new File(path);
        String[] fileNames = depotDir.list();
        for (int i = 0; i < fileNames.length; i++) {
            File file = new File(depotDir.getPath() + File.separator + fileNames[i]);
            files.add(file);
            Date fileLastModified = new Date(file.lastModified());
            if (lastModified == null || lastModified.compareTo(fileLastModified) < 0) {
                lastModified = fileLastModified;
            }
        }
        Collections.sort(files, new FileComparator());
    }
    /** Get files sorted in reverse chronological order */
    public synchronized Collection getFiles() {
        return files;
    }
    
    public synchronized Date getLastUpdateDate() {
        return lastModified;
    }

    /** Helps to sort files in reverse chrono order */
    class FileComparator implements Comparator {
        public int compare(Object o1, Object o2) {
            File file1 = (File)o1;
            File file2 = (File)o2;
            if (file1.lastModified() == file2.lastModified()) return 0;
            else if (file1.lastModified() < file2.lastModified()) return 1;
            else return -1;
        }
    }
}

import java.io.*;
import java.util.*;

import com.sun.syndication.feed.WireFeed;
import com.sun.syndication.feed.synd.*;
import com.sun.syndication.io.WireFeedOutput;

/**
* 使用Java生成newsfeed
* @author blurxx
*
*/
public class DepotNewsfeedWriter {

    private static final List Collections = null;

    private Depot depot;

    public DepotNewsfeedWriter(Depot depot) {
        this.depot = depot;
    }

    public void write(Writer writer, String baseURL, String format)
            throws Exception {
        SyndFeed feed = new SyndFeedImpl();
        feed.setFeedType(format);
        feed.setLanguage("en-us");
        feed.setTitle("File Depot Newsfeed");
        feed.setDescription("Newly uploaded files in the File Depot");
        feed.setLink(baseURL);
        feed.setUri(baseURL + "/depot-newsfeed");
        feed.setPublishedDate(depot.getLastUpdateDate());

        SyndLink selfLink = new SyndLinkImpl();
        selfLink.setHref(feed.getUri());
        selfLink.setRel("self");
        feed.setLinks(Collections); //

        ArrayList<SyndEntry> entries = new ArrayList<SyndEntry>();
        Iterator files = depot.getFiles().iterator();
        while (files.hasNext()) {
            File file = (File) files.next();

            SyndEntry entry = new SyndEntryImpl();
            String url = baseURL + file.getName();
            entry.setLink(url);
            entry.setUri(url);
            entry.setTitle(file.getName());
            entry.setPublishedDate(new Date(file.lastModified())); // 索取文件最后一次修改时间
            entry.setUpdatedDate(new Date(file.lastModified()));

            SyndContent description = new SyndContentImpl();
            description.setValue("Click <a href='" + url + "'>"
                    + file.getName() + "</a>to download the file.");
            entry.setDescription(description);
            entries.add(entry);// 包含多个entry
        }
        feed.setEntries(entries);

        WireFeedOutput output = new WireFeedOutput();
        WireFeed wireFeed = feed.createWireFeed();
        output.output(wireFeed, writer);
    }

    /**
     * @param args
     * @throws Exception
     */
    public static void main(String[] args) throws Exception {
        if (args.length < 3) {
            System.out.println("USER:DepotNewsfeedWriter "
                    + "[depotDir] [depotUrl] [file] [format]");
            return;
        }
        String depotDir =  args[0];
        Depot depot = new FileDepot(depotDir);
        DepotNewsfeedWriter newsfeedWriter = new DepotNewsfeedWriter(depot);

        new DepotNewsfeedWriter(depot); // |#11

        String depotUrl = args[1]; // 输入1

        String filePath = args[2]; // 输入2

        String format = args[3]; // 输入3

        FileWriter writer = new FileWriter(filePath);

        newsfeedWriter.write(writer, depotUrl, format);

    }
}

package com.manning.blogapps.chapter08.filedpot;

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

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

public class DepotNewsfeedServlet extends HttpServlet {

    private static final long serialVersionUID = 182023042307203449L;

    /**
     * Constructor of the object.
     */
    public DepotNewsfeedServlet() {
        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 {

        ServletContext application = this.getServletContext();
        Depot depot = (Depot) application.getAttribute("depot");
        if(depot == null){
            depot = new FileDepot(request.getRealPath("/depot"));
            application.setAttribute("depot", depot);
        }
        try{
            String format = request.getParameter("format");
            if(format ==null)
                format ="rss_2.0";
            if(format.startsWith("rss")){
                response.setContentType("application/rss+xml;charset=utf-8");
            }else{
                response.setContentType("application/atom+xml;charset=utf-8");
            }
            String depotUrl = request.getRequestURI().toString();
            //String depotUrl = url.substring(0,url.lastIndexOf("/"));
            depotUrl = "http://"+request.getRemoteHost()+depotUrl;
            DepotNewsfeedWriter depotWriter = new DepotNewsfeedWriter(depot);
            depotWriter.write(response.getWriter(), depotUrl, format);
        }
        catch(Exception ex){
            String msg ="ERROR:generating newsfeed";
            log(msg,ex);
            response.sendError(HttpServletResponse.SC_INTERNAL_SERVER_ERROR,msg);
        }
    }

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