Java -- & gt; implements resumable upload (download) and java -- resumable upload

Java --> implements resumable upload (download), java -- resumable upload

--> Resumable upload: stops or closes the program just like thunder downloads a file. The next download starts from the last download, rather than starting with another download...

--> RandomAccessFile --> pointer (File pointer) --> seek (move file pointer) --> resumable upload

Package com. dragon. java. downloadfile; import java. io. file; import java. io. IOException; import java. io. randomAccessFile;/* resumable upload: This is very important for downloading software! --> The first download of 100 bytes --> the second download of 101 bytes... find a way to know where the last download was broken. The location where the last download has been made. Write down the breakpoint location ------> A third-party file is required to remember the breakpoint location */public class Test {public static void main (String args []) {File srcFile = new File ("D:/Java4Android/01_Java archaeology/01_java .mp4"); File desDir = new File ("f:/vidio"); copyFileToDir (srcFile, desDir);} public static void copyFileToDir (File srcFile, File desDir) {desDir. mkdirs (); // create the configuration File configFile = new File (desDir, srcFile. getName (). split ("\\. ") [0] + ". c Onfig "); // create the target File desFile = new File (desDir, srcFile. getName (); if (! ConfigFile. exists () & desFile. exists () {System. out. println ("this file has been downloaded! "); Return;} RandomAccessFile rafSrc = null; RandomAccessFile rafDes = null; RandomAccessFile rafConfig = null; try {rafSrc = new RandomAccessFile (srcFile," r "); rafDes = new RandomAccessFile (desFile, "rw"); rafConfig = new RandomAccessFile (configFile, "rw"); // set the target file to be as long as the source file. setLength (srcFile. length (); // set the configuration file length to 8 to prevent the first download from an EOF exception rafConfig. setLength (8); // download continues from the last download location! Long pointer = rafConfig. readLong (); System. out. println ("downloaded:" + (float) pointer/srcFile. length () * 100 + "%"); rafSrc. seek (pointer); rafDes. seek (pointer); // set a small point for the length of a single transmission, so that you can check whether the resumable data transfer byte [] buffer = new byte [32]; int len =-1; // at the beginning of each copy, the pointer of the source file and the pointer of the target file must be read from the last disconnected position while (len = rafSrc. read (buffer ))! =-1) {rafDes. write (buffer, 0, len); // when writing the configuration file, every time the file pointer is moved to the original position --> this way, the first eight bytes of rafConfig will be stored forever. seek (0); // The sum of each copy. record the position of the file pointer for resumable data transfer. RafConfig. writeLong (rafSrc. getFilePointer ();} catch (IOException e) {System. out. println (e);} finally {try {rafSrc. close (); rafDes. close (); rafConfig. close ();} catch (IOException e) {System. out. println (e);} // Delete the configuration file System after the stream is closed. out. println ("Download successful! "); ConfigFile. delete ();}}}

--> Simulate simple resumable upload through replication...