feature/BAEL-6712-split large file (#15262)

* feature/BAEL-6712-split lareg file

* feature/BAEL-6712-split lareg file

* bael-6712 review comment fix

---------

Co-authored-by: Sachin kumar <sachin.n.kumar@oracle.com>

core-java-modules/core-java-io-5/src/main/java/com/baeldung/splitlargefile/SplitLargeFile.java

@@ -0,0 +1,59 @@
+package com.baeldung.splitlargefile;
+
+import java.io.File;
+import java.io.FileOutputStream;
+import java.io.IOException;
+import java.io.InputStream;
+import java.nio.file.Files;
+import java.util.ArrayList;
+import java.util.List;
+
+import org.apache.commons.io.FilenameUtils;
+
+class SplitLargeFile {
+
+    public List<File> splitByFileSize(File largeFile, int maxSizeOfSplitFiles,
+            String splitedFileDirPath) throws IOException {
+        List<File> listOfSplitFiles = new ArrayList<>();
+        try (InputStream in = Files.newInputStream(largeFile.toPath())) {
+            final byte[] buffer = new byte[maxSizeOfSplitFiles];
+            int dataRead = in.read(buffer);
+            while (dataRead > -1) {
+                File splitFile = getSplitFile(FilenameUtils.removeExtension(largeFile.getName()),
+                        buffer, dataRead, splitedFileDirPath);
+                listOfSplitFiles.add(splitFile);
+                dataRead = in.read(buffer);
+            }
+        }
+        return listOfSplitFiles;
+    }
+
+    private File getSplitFile(String largeFileName, byte[] buffer, int length,
+            String splitedFileDirPath) throws IOException {
+        File splitFile = File.createTempFile(largeFileName + "-", "-split",
+                new File(splitedFileDirPath));
+        try (FileOutputStream fos = new FileOutputStream(splitFile)) {
+            fos.write(buffer, 0, length);
+        }
+        return splitFile;
+    }
+
+    public List<File> splitByNumberOfFiles(File largeFile, int noOfFiles, String splitedFileDirPath)
+            throws IOException {
+        return splitByFileSize(largeFile, getSizeInBytes(largeFile.length(), noOfFiles),
+                splitedFileDirPath);
+    }
+
+    private int getSizeInBytes(long largefileSizeInBytes, int numberOfFilesforSplit) {
+        if (largefileSizeInBytes % numberOfFilesforSplit != 0) {
+            largefileSizeInBytes = ((largefileSizeInBytes / numberOfFilesforSplit) + 1)
+                    * numberOfFilesforSplit;
+        }
+        long x = largefileSizeInBytes / numberOfFilesforSplit;
+        if (x > Integer.MAX_VALUE) {
+            throw new NumberFormatException("size too large");
+
+        }
+        return (int) x;
+    }
+}

core-java-modules/core-java-io-5/src/test/java/com/baeldung/splitlargefile/SplitLargeFileUnitTest.java

@@ -0,0 +1,41 @@
+package com.baeldung.splitlargefile;
+
+import java.io.File;
+import java.io.IOException;
+import java.nio.file.Files;
+import java.nio.file.Path;
+import java.nio.file.Paths;
+
+import org.junit.BeforeClass;
+
+public class SplitLargeFileUnitTest {
+
+    @BeforeClass
+    public static void prepareData() throws IOException {
+        Files.createDirectories(Paths.get("target/split"));
+    }
+
+    private String splitedFileDirPath() throws Exception {
+        return Paths.get("target").toString() + "/split";
+    }
+
+    private Path largeFilePath() throws Exception {
+        return Paths.get(this.getClass().getClassLoader().getResource("large-file.txt").toURI());
+    }
+
+
+    @org.junit.Test
+    public void givenLargeFile_whenSplitLargeFile_thenSplitBySize() throws Exception {
+        File input = largeFilePath().toFile();
+        SplitLargeFile slf = new SplitLargeFile();
+        slf.splitByFileSize(input, 1024_000, splitedFileDirPath());
+    }
+
+    @org.junit.Test
+    public void givenLargeFile_whenSplitLargeFile_thenSplitByNumberOfFiles() throws Exception {
+        File input = largeFilePath().toFile();
+        SplitLargeFile slf = new SplitLargeFile();
+        slf.splitByNumberOfFiles(input, 3, splitedFileDirPath());
+    }
+
+}