sitefilefetch.java

j2me的基于http协议的断点续传。支持多线程的断点续传。

/**
 * SiteFileFetch.java
 * 
 * There are five classes:
 * SiteFileFetch.java: for whole file fetch and control the threads of FileSplitterFetch
 * FileSplitterFetch.java: for fetch partials of given file
 * FileAccess.java: for file storage
 * SiteInfoBean.java: for information storage
 * Utility.java: tools such as log
 *  
 */
package NetFox;

import java.io.*;
import javax.microedition.io.file.*;
import javax.microedition.io.*;

import FileUtils;

public class SiteFileFetch extends Thread {
    SiteInfoBean siteInfoBean = null;
    long[] m_nOrgStartPos;
    long[] nStartPos; 
    long[] nEndPos;
    FileSplitterFetch[] fileSplitterFetch;
    long nFileLength;
    boolean bFirst = true; // 是否第一次取文件
    boolean bStop = false; // 停止标志
    FileConnection tmpFile; // 文件下载的临时信息
    FileSelector fSel = null;
    
    public SiteFileFetch(SiteInfoBean bean, FileSelector fSel) throws IOException {
        this.fSel = fSel;
        bean.printBean();
        siteInfoBean = bean;
        String tmpFn = bean.getSFilePath() + bean.getSFileName() + ".info";
        Utility.log("check file " + tmpFn + "\n");
        tmpFile = Utility.createFileConn(tmpFn);
        boolean bGotPos = false;
        if( tmpFile.exists() ) 
        {
            Utility.log("info file exists, read pos\n");
            bGotPos = read_nPos();
        }
        
        if( !bGotPos )
        {
        	Utility.log("info file does NOT exist, init new one\n");
        	tmpFile.create();
            m_nOrgStartPos = new long[bean.getNSplitter()];
            nStartPos = new long[bean.getNSplitter()];
            nEndPos = new long[bean.getNSplitter()];
        }
        else
        	bFirst = false;
    }

    public void run() {
        Utility.log("SiteFileFetch runs\n");
        // 获得文件长度
        // 分割文件
        // 实例FileSplitterFetch
        // 启动FileSplitterFetch线程
        // 等待子线程返回
        try 
        {
            if( bFirst )
            {
                nFileLength = getFileSize();
                if (nFileLength == -1) 
                {
                    Utility.log("File Length is not known!\n");
                    return;
                }
                else if (nFileLength == -2)
                {
                    Utility.log("File is not access!\n");
                    return;
                }
                else
                {
                    for (int i = 0; i < nStartPos.length; i++) 
                    {
                        m_nOrgStartPos[i] = (long)(i * (nFileLength / nStartPos.length));
                        nStartPos[i] = m_nOrgStartPos[i]; 
                    }
                    
                    for(int i = 0;i < nEndPos.length - 1; i++)
                    {
                        nEndPos[i] = nStartPos[i + 1];
                    }
                    
                    nEndPos[nEndPos.length - 1] = nFileLength;
                }
            }


            // start download thread            
            fileSplitterFetch = new FileSplitterFetch[nStartPos.length];
            for (int i = 0; i < nStartPos.length; i++) 
            {
                if( nStartPos[i] < nEndPos[i] ) 
                {
                    fileSplitterFetch[i] = new FileSplitterFetch(siteInfoBean.getSSiteHost(),
                        siteInfoBean.getSSiteURL(), 
                        siteInfoBean.getSFilePath() + siteInfoBean.getSFileName() + i,
                        m_nOrgStartPos[i],
                        nStartPos[i], 
                        nEndPos[i], 
                        i);
                    Utility.log("Thread " + i + ": nOrgStartPos = " + m_nOrgStartPos[i] + ", nStartPos = " + nStartPos[i] + ", nEndPos = " + nEndPos[i]);
                    fileSplitterFetch[i].start();
                }
            }
            
            // 等待子线程结束
            // int count = 0;
            // 是否结束while循环
            
            boolean breakWhile = false;
            while (!bStop)
            {
                write_nPos();
                Utility.sleep(Utility.SLEEP);
                breakWhile = true;
                for( int i = 0; i < nStartPos.length; i++ ) 
                {
                    if( !fileSplitterFetch[i].bDownOver )
                    {
                        breakWhile = false;
                        break;
                    }
                }
                
                if(breakWhile)
                    break;
            }

            if( bStop )
            {
                // user stop, we need to write pos too
                write_nPos();
                tmpFile.close();
            
                checkProgress(fileSplitterFetch);
                Utility.log("User stopped download.");
            }
            else
            {
            	Utility.log("Download finished." + FileUtils.getDefaultRoot());
            	
            	String[] asFile = new String[fileSplitterFetch.length];
            	for( int i=0; i<asFile.length; i++ )
            	{
            		asFile[i] = siteInfoBean.getSFileName() + i;
            	}
            	FileUtils.mergeFiles(null, siteInfoBean.getSFileName(), null, asFile, 0);

            	Utility.log("Merge finished.");

            	for( int i=0; i<asFile.length; i++ )
            	{
            		FileUtils.deleteFile(null, asFile[i]);
            	}
            	Utility.log("Delete file finished.");
            	
            	tmpFile.delete();
            	
                fSel.notifyProgress(true, 0, 0);
                Utility.log("File download is finished.");
            }            
        } catch(Exception e) {
            Utility.log(e.getMessage());
        }
    }

    /**
     * Check download progress and notify FileSelector
     *
     */
    private int checkProgress(FileSplitterFetch[] fSplitter) {
        int transferred = 0;
        int left = 0;
        
        for (int i = 0; i < nStartPos.length; i++) {
            if (fSplitter[i].bStop) {
                transferred += fSplitter[i].nStartPos;
                left += fSplitter[i].nEndPos - fSplitter[i].nStartPos;
            }
        }
        Utility.log("In checkProgress, transferred:" + transferred
            + " left:" + left);
        transferred /= 1000;
        left /= 1000;
        fSel.notifyProgress(false, transferred, left);
        
        return 0;
    }
    
    /**
     * Get download file length
     */
    public long getFileSize() {
        long nFileLength = -1;
        try {
            HttpConnection httpConn = Utility.createHttpConn(Utility.DOWNLOAD_HOST, Utility.FILE_NAME);
            httpConn.setRequestMethod(HttpConnection.POST);       
            httpConn.setRequestProperty(Utility.PROP_USER_AGENT, Utility.MOBILE_UA);
            
            int responseCode = httpConn.getResponseCode();
            
            if (responseCode >= 400) {
                Utility.log("responseCode=" + responseCode);
                return -2; // -2 represent access is error
            }
            
            nFileLength = httpConn.getLength();
            Utility.log("getLength =" + nFileLength);
            
            /*
            String sHeader;
            for (int i = 1 ; ; i++) {
                sHeader = httpConn.getHeaderFieldKey(i);
                
                if (sHeader != null) 
                {
                    //Utility.log(sHeader);
                    if (sHeader.equalsIgnoreCase("content-length")) 
                    {
                        nFileLength = Integer.parseInt(httpConn.getHeaderField(sHeader));
                        Utility.log("content-length= " + nFileLength);
                        break;
                    }
                    else
                    	Utility.log(sHeader + "=" + httpConn.getHeaderField(sHeader));
                } else
                    break;
            }
            */
            
            httpConn.close();
        } catch(IOException e) {
            Utility.log(e.getMessage());
        } catch(Exception e) {
            Utility.log(e.getMessage());
        }
        
        Utility.log("file length === " + nFileLength);
        return nFileLength;
    }
    
    /**
     *  Store the download file offset
     */
    private void write_nPos() {
        DataOutputStream output = null;
        
        try 
        {
            output = tmpFile.openDataOutputStream();
            output.writeInt(nStartPos.length);
 
            for (int i = 0; i < nStartPos.length; i++) 
            {
            	output.writeLong(fileSplitterFetch[i].m_nOrgStartPos);
                output.writeLong(fileSplitterFetch[i].nStartPos);
                output.writeLong(fileSplitterFetch[i].nEndPos);
            }
            output.close();
        } catch (IOException e) {
            Utility.log(e.getMessage());
        } catch (Exception e) {
            Utility.log(e.getMessage());
        }
    }
    
    /**
     * Read the download file offset
     * 
     */
    private boolean read_nPos() {
        DataInputStream input = null;

        try 
        {
            input = tmpFile.openDataInputStream();
            int nCount = input.readInt();
            m_nOrgStartPos = new long[nCount];
            nStartPos = new long[nCount];
            nEndPos = new long[nCount];
            for (int i = 0; i < nStartPos.length; i++) 
            {
            	m_nOrgStartPos[i] = input.readLong();
                nStartPos[i] = input.readLong();
                nEndPos[i] = input.readLong();
            }
            input.close();
            
            return true;
        } 
        catch(IOException e) 
        {
            Utility.log(e.getMessage());
        	try
        	{
        		tmpFile.truncate(0);
        	}
        	catch( IOException e1 )
        	{
                Utility.log(e1.getMessage());        		
        	}
        } 
        return false;
    }
    
    /**
     * Stop download
     * 
     */
    public void siteStop() {
        bStop = true;
        for (int i = 0; i < nStartPos.length; i++)
            fileSplitterFetch[i].splitterStop();
    }

    /**
     * Restart download
     * 
     */
    public void siteStart() {
        bStop = false;
        for (int i = 0; i < nStartPos.length; i++)
            fileSplitterFetch[i].splitterStart();
    }
}