Latest --- multi-thread download of java files

Import java. io. inputStream; import java. io. randomAccessFile; import java.net. httpURLConnection; import java.net. URL; public class Demo {// define the number of threads public static int threadCount = 5; public static void main (String [] args) throws Exception {// 1, connect to the server, obtain a file. The file size is the same as that of the server. The temporary file String path = "http: // 172.22.64.193: 8080/0001 AndroidWebService/test.exe "; URL url = new URL (path); HttpURLConnection conn = (HttpUR LConnection) url. openConnection (); // set timeout conn. setConnectTimeout (5000); // sets the Request Method conn. setRequestMethod ("GET"); // GET the server's return code int code = conn. getResponseCode (); // judge the return code if (code = 200) {// obtain the returned length int length = conn. getContentLength (); System. out. println ("total file length:" + length); // create a temporary file RandomAccessFile raf = new RandomAccessFile ("temp.exe ", "rwd"); // specifies the size of the temporary file raf. setLength (length); // release the resource raf. cl Ose (); // average file size of each thread int blockSize = length/threadCount; for (int threadId = 1; threadId <= threadCount; threadId ++) {// download position starting from the thread int startIndex = (threadId-1) * blockSize; // The end position of the thread int endIndex = threadId * blockSize-1; // determine whether it is the last thread if (threadId = threadCount) {// set the end position to the end of the file endIndex = length;} System. out. println ("thread:" + threadId + "Download: >>>>>>>>>" + startIndex + ">>>>>>>>>" + endIndex ); new DownlodeThread (path, threadId, startIndex, endIndex ). start () ;}}/ *** subthread class for downloading files, each Thread downloads the file data at the corresponding location ** @ author MartinDong **/public static class DownlodeThread extends Thread {private String path; private int threadId; private int startIndex; private int endIndex; /***** @ param path * File Download path * @ param threadId * thread id * @ param startIndex * thread start position * @ param endIndex * thread end position */ public DownlodeThread (Stri Ng path, int threadId, int startIndex, int endIndex) {this. path = path; this. threadId = threadId; this. startIndex = startIndex; this. endIndex = endIndex ;}@ Overridepublic void run () {try {// convert the address to URLURL url = new URL (path); // obtain the http connection HttpURLConnection conn = (HttpURLConnection) url. openConnection (); // set the Connection Request Method conn. setRequestMethod ("GET"); // important: Requests the server to download part of the file, specifying the position of the file conn. setRequestProperty ("Range", "byt Es = "+ startIndex +"-"+ endIndex); // set the timeout value conn. setReadTimeout (5000); // get the server status code. The value 200 indicates that all requested resources are responded = OK, 206 response = okint code = conn for some requested resources. getResponseCode (); System. out. println ("code:" + code); // The returned file stream InputStream is = conn. getInputStream (); // create a temporary file named RandomAccessFile raf = new RandomAccessFile ("temp.exe", "rwd"); // move the pointer to the specified file location, raf. seek (startIndex); // creates an intermediate buffer byte array byte [] buffer = new byte [1024]; int length = 0; while (length = is. read (buffer ))! =-1) {raf. write (buffer, 0, length);} is. close (); raf. close (); System. out. println ("thread:" + threadId + "download completed ............ ");} catch (Exception e) {// TODO Auto-generated catch blocke. printStackTrace ();}}}}