Split and merge large files to achieve split and merge

Split and merge large files to achieve split and merge

1 public void cutFile (File bigFile, File destFile, int cutSize) {2 3 FileInputStream inputStream = null; 4 int size = 1024*1024; // 1 M 5 try {6 if (! DestFile. isDirectory () {// if the address for saving the split file is not the path 7 destFile. mkdir (); // create path 8} 9 size = size * cutSize; // split the file size in the unit of M, 10 int length = (int) bigFile. length (); // obtain the size of a large file (in Unit B) 11 int num = length/size; // calculate the number of small files to be split (the size of each small file is in MB) 12 int yu = length % size; // the size of the file to be divided (M) 13 14 String bigFilePath = bigFile. getAbsolutePath (); // obtain the complete path information of a large file (including the file name) 15 int fileNew = bigFilePath. lastIndexOf (". "); // get the". "Index 16 String suffix = bigFilePath. substring (fileNew, bigFilePath. length (); // get the suffix, that is, the file type 17 18 inputStream = new FileInputStream (bigFile ); // get large File input stream 19 File [] smallFile = new File [num + 1]; // create an array of files for saving small files 20 int begin = 0; 21 for (int I = 0; I <num; I ++) {22 smallFile [I] = new File (bigFile. getAbsolutePath () + "\" + (I + 1) + suffix + ". tem "); // specify the name of the small file 23 if (! SmallFile [I]. isFile () {24 smallFile [I]. createNewFile (); // create this file 25} 26 FileOutputStream outputStream = new FileOutputStream (smallFile [I]); // create a small file. The output stream is 27 byte [] small = new byte [size]; 28 inputStream. read (small); // read the small file byte 29 outputStream. write (small); // write byte data to small files 30 begin = begin + size; 31 outputStream. close (); 32} 33 if (yu! = 0) {// The remainder object size (M) is not empty. 34. smallFile [num] = new File (bigFile. getAbsolutePath () + "\" + (num + 1) + suffix + ". tem "); 35 if (! SmallFile [num]. isFile () {36 smallFile [num]. createNewFile (); // Create File 37} 38 FileOutputStream outputStream = new FileOutputStream (smallFile [num]); 39 byte [] bytes = new byte [yu]; 40 inputStream. read (bytes); // read the byte 41 outputStream. write (bytes); // write data to the file 42 outputStream. close (); 43} 44} catch (Exception e) {45 e. printStackTrace (); 46} 47}

2. merge processing

1 public void closeFile (File [] files, File closeDir, String hz) {2 try {3 File closeFile = new File (closeDir. getAbsoluteFile () + "\ close" + hz); // specify the merged file name (including path) 4 if (! CloseFile. isFile () {5 closeFile. createNewFile (); // create file 6} 7 8 FileOutputStream outputStream = new FileOutputStream (closeFile); // create file output stream 9 for (int I = 0; I <files. length; I ++) {10 FileInputStream inputStream = new FileInputStream (closeFile); // create a file input stream 11 int len = (int) files [I]. length (); // obtain the size of a single sub-file 12 byte [] bytes = new byte [len]; 13 inputStream. read (bytes); 14 outputStream. write (bytes); 15 inputStream. close (); 16} 17 outputStream. close (); 18} catch (Exception e) {19 e. printStackTrace (); 20} 21}