java的http断点续传原理(二)

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 Positionlong nEndPos; //File Snippet End Positionint nThreadID; //Thread's IDboolean bDownOver = false; //Downing is overboolean bStop = false; //Stop identicalFileAccessI fileAccessI = null; //File Access interfacepublic FileSplitterFetch(String sURL,String sName,long nStart,long nEnd,int id) throws IOException{this.sURL = sURL;this.nStartPos = nStart;this.nEndPos = nEnd;nThreadID = id;fileAccessI = new FileAccessI(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 += fileAccessI.write(b,0,nRead);//if(nThreadID == 1)// Utility.log("nStartPos = " + nStartPos + ", nEndPos = " + nEndPos); }Utility.log("Thread " + nThreadID + " is over!");bDownOver = true;//nPos = fileAccessI.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));elsebreak;}}public void splitterStop(){bStop = true;}}/***FileAccess.java*/package NetFox;import java.io.*;public class FileAccessI implements Serializable{ RandomAccessFile oSavedFile;long nPos;public FileAccessI() throws IOException{this("",0);}public FileAccessI(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;}}/***SiteInfoBean.java*/package NetFox;public class SiteInfoBean {private String sSiteURL; //Site's URLprivate String sFilePath; //Saved File's Pathprivate String sFileName; //Saved File's Nameprivate int nSplitter; //Count of Splited Downloading Filepublic SiteInfoBean(){//default value of nSplitter is 5this("","","",5);}public SiteInfoBean(String sURL,String sPath,String sName,int nSpiltter) {sSiteURL= sURL;sFilePath = sPath;sFileName = sName;this.nSplitter = nSpiltter;}public String getSSiteURL(){return sSiteURL;}public void setSSiteURL(String value) {sSiteURL = value;}public String getSFilePath(){return sFilePath;}public void setSFilePath(String value) {sFilePath = value;}public String getSFileName(){return sFileName;}public void setSFileName(String value) {sFileName = value;}public int getNSplitter(){return nSplitter;}public void setNSplitter(int nCount) {nSplitter = nCount;}}/***Utility.java*/package NetFox;public class Utility {public Utility(){}public static void sleep(int nSecond) {try{Thread.sleep(nSecond);}catch(Exception e){e.printStackTrace ();}}public static void log(String sMsg){System.err.println(sMsg);}public static void log(int sMsg){System.err.println(sMsg);}}/***TestMethod.java*/package NetFox;public class TestMethod {public TestMethod(){ ///xx/weblogic60b2_win.exetry{SiteInfoBean bean = newSiteInfoBean("http://localhost/xx/weblogic60b2_win.exe","L:\\temp","weblogic60b2_w in.exe",5);//SiteInfoBean bean = newSiteInfoBean("http://localhost:8080/down.zip","L:\\temp","weblogic60b2_win.exe",5) ;SiteFileFetch fileFetch = new SiteFileFetch(bean);fileFetch.start();}catch(Exception e){e.printStackTrace ();}}public static void main(String[] args){new TestMethod();。