JAVA断点续传(B/S)（2）

/*
 **FileSplitterFetch.java
 */
package NetFox;

import java.io.*;
import java.net.*;

public class FileSplitterFetch extends Thread {
    String sURL; // File URL

    long nStartPos; // File Snippet Start Position

    long nEndPos; // File Snippet End Position

    int nThreadID; // Thread's ID

    boolean bDownOver = false; // Downing is over

    boolean bStop = false; // Stop identical

    FileAccess FileAccess = null; // File Access interface

    public FileSplitterFetch(String sURL, String sName, long nStart, long nEnd,
            int id) throws IOException {
        this.sURL = sURL;
        this.nStartPos = nStart;
        this.nEndPos = nEnd;
        nThreadID = id;
        FileAccess = new FileAccess(sName, nStartPos);
    }

    public void run() {
        while (nStartPos < nEndPos && !bStop) {
            try {
                URL url = new URL(sURL);
                HttpURLConnection httpConnection = (HttpURLConnection) url
                        .openConnection();
                httpConnection.setRequestProperty("User-Agent", "NetFox");
                String sProperty = "bytes=" + nStartPos + "-";
                httpConnection.setRequestProperty("RANGE", sProperty);
                Utility.log(sProperty);
                InputStream input = httpConnection.getInputStream();
                // logResponseHead(httpConnection);
                byte[] b = new byte[1024];
                int nRead;
                while ((nRead = input.read(b, 0, 1024)) > 0
                        && nStartPos < nEndPos && !bStop) {
                    nStartPos += FileAccess.write(b, 0, nRead);
                    // if(nThreadID == 1)
                    // Utility.log("nStartPos = " + nStartPos + ", nEndPos = " +
                    // nEndPos);
                }
                Utility.log("Thread " + nThreadID + " is over!");
                bDownOver = true;
                // nPos = FileAccess.write (b,0,nRead);
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
    }

    // 打印回应的头信息
    public void logResponseHead(HttpURLConnection con) {
        for (int i = 1;; i++) {
            String header = con.getHeaderFieldKey(i);
            if (header != null)
                // responseHeaders.put(header,httpConnection.getHeaderField(header));
                Utility.log(header + " : " + con.getHeaderField(header));
            else
                break;
        }
    }

    public void splitterStop() {
        bStop = true;
    }
}

 

/*
 **FileAccess.java
 */
package NetFox;

import java.io.*;

public class FileAccess implements Serializable {

    private static final long serialVersionUID = 1L;

    RandomAccessFile oSavedFile;

    long nPos;

    public FileAccess() throws IOException {
        this("", 0);
    }

    public FileAccess(String sName, long nPos) throws IOException {
        oSavedFile = new RandomAccessFile(sName, "rw");
        this.nPos = nPos;
        oSavedFile.seek(nPos);
    }

    public synchronized int write(byte[] b, int nStart, int nLen) {
        int n = -1;
        try {
            oSavedFile.write(b, nStart, nLen);
            n = nLen;
        } catch (IOException e) {
            e.printStackTrace();
        }
        return n;
    }
}