java的http断点续传原理(二).docx

java的http断点续传原理(二)//获得文件长度public long getFileSize(){int nFileLength = -1;try{URL url = new URL(siteInfoBean.getSSiteURL());HttpURLConnection httpConnection = (HttpURLConnection)url.openConnection ();httpConnection.setRequestProperty(User-Agent,NetFox);int responseCode=httpConnection.getResponseCode();if(responseCode=400){processErrorCode(responseCode);return -2; //-2 represent access is error}String sHeader;for(int i=1;;i++){//DataInputStream in = new DataInputStream(httpConnection.getInputStream ());//Utility.log(in.readLine());sHeader=httpConnection.getHeaderFieldKey(i);if(sHeader!=null){if(sHeader.equals(Content-Length)){nFileLength = Integer.parseInt(httpConnection.getHeaderField(sHeader));break;}}elsebreak;}}catch(IOException e){e.printStackTrace ();}catch(Exception e){e.printStackTrace ();}Utility.log(nFileLength);return nFileLength;}//保存下载信息(文件指针位置)private void write_nPos(){try{output = new DataOutputStream(new FileOutputStream(tmpFile));output.writeInt(nStartPos.length);for(int i=0;i p {// output.writeLong(nPos[i]);output.writeLong(fileSplitterFetch[i].nStartPos);output.writeLong(fileSplitterFetch[i].nEndPos);}output.close();}catch(IOException e){e.printStackTrace ();}catch(Exception e){e.printStackTrace ();}}//读取保存的下载信息(文件指针位置)private void read_nPos(){try{DataInputStream input = new DataInputStream(new FileInputStream(tmpFile));int nCount = input.readInt();nStartPos = new long[nCount];nEndPos = new long[nCount];for(int i=0;i p {nStartPos[i] = input.readLong();nEndPos[i] = input.readLong();}input.close();}catch(IOException e){e.printStackTrace ();}catch(Exception e){e.printStackTrace ();}}private void processErrorCode(int nErrorCode){System.err.println(Error Code : + nErrorCode);}//停止文件下载public void siteStop(){bStop = true;for(int i=0;i p fileSplitterFetch[i].splitterStop();}}/***FileSplitterFetch.java*/package NetFox;import java.io.*;import .*;public class FileSplitterFetch extends Thread {String sURL; //File URLlong nStartPos; //File Snippet Start Positio