源码简介

实现android 上面多线程断点续传下载 ，支持暂停，记忆任务。
源码运行截图

源码片段

try { 
                HttpURLConnection http = (HttpURLConnection) downUrl 
                        .openConnection(); 
                http.setConnectTimeout(5 * 1000); 
                http.setRequestMethod("GET"); 
                http.setRequestProperty("Accept", "image/gif, image/jpeg, image/pjpeg, image/pjpeg,application/x-shockwave-flash, application/xaml+xml,application/vnd.ms-xpsdocument, application/x-ms-xbap,application/x-ms-application, application/vnd.ms-excel, application/vnd.ms-powerpoint, application/msword"); 
            //  http.setRequestProperty(, null); // 设置客户端可以接受的返回数据类型 
                  
                http.setRequestProperty("Accept-Language", "zh-CN"); 
                http.setRequestProperty("Referer", downUrl.toString());// 设置请求的来源，便于对访问来源进行统计 
                http.setRequestProperty("Charset", "UTF-8"); 
  
                // 计算该线程下载的开始位置 
                int startPos = block * (threadId - 1) + downloadedLength; 
                  
                /** 
                 * 每块结束的位置（***一块需特殊处理，因为不能平均分配每块大下，***一块可能会有余数） 
                 */ 
                //int endPosition = (i + 1) != threadCount ? ((i + 1) * blockSize - 1): fileSize; 
                // 计算该线程下载的结束位置 
                int endPos = threadId!=threadCount? (block *threadId):fileSize; 
                // 设置获取实体数据的范围,如果超过了实体数据的大小会自动返回实际的数据大小 
                http.setRequestProperty("Range", "bytes=" + startPos + "-"+ endPos); 
                // 客户端用户代理 
                http.setRequestProperty("User-Agent", 
                        "Mozilla/4.0 (compatible; MSIE 8.0;" 
                                + " Windows NT 5.2; Trident/4.0;" 
                                + " .NET CLR 1.1.4322;" 
                                + " .NET CLR 2.0.50727;" 
                                + " .NET CLR 3.0.04506.30;" 
                                + " .NET CLR 3.0.4506.2152;" 
                                + " .NET CLR 3.5.30729)"); 
  
                // 使用长连接 
                http.setRequestProperty("Connection", "Keep-Alive"); 
                // 获取远程连接的输入流 
                InputStream inStream = http.getInputStream(); 
                // 设置本地数据缓存的大小为1M 
                byte[] buffer = new byte[1024]; 
                // 设置每次读取的数据量 
                int offset = 0; 
                // 打印该线程开始下载的位置 
                print("Thread " + this.threadId 
                        + " starts to download from position " + startPos); 
                RandomAccessFile threadFile = new RandomAccessFile( 
                        this.saveFile, "rwd"); 
                // 文件指针指向开始下载的位置 
                threadFile.seek(startPos); 

源码链接：http://down.51cto.com/data/1980815