Java Utililty Methods Zip Files

String raw = file.getAbsolutePath().replace("\\", "/");
if (raw.length() == skipprefix) {
    if (file.isDirectory()) {
        File[] children = file.listFiles();
        if (children != null) {
            for (File child : children) {
                addFileToZip(skipprefix, child, zipper);
} else {
    String path = raw.substring(skipprefix + 1);
    if (file.isDirectory()) {
        File[] children = file.listFiles();
        if (children != null) {
            for (File child : children) {
                addFileToZip(skipprefix, child, zipper);
    } else {
        ZipEntry entry = new ZipEntry(path);
        zipper.putNextEntry(entry);
        try (FileInputStream in = new FileInputStream(file)) {
            copyStream(in, zipper);
        zipper.closeEntry();

if (flag == true) {
    zip.putNextEntry(new ZipEntry(path + "/" + srcFile.getName() + "/"));
} else {
    if (srcFile.isDirectory()) {
        addFolderToZip(path, srcFile, zip);
    } else {
        int len;
        byte[] buf = new byte[1024];
...

if (srcFile.isDirectory()) {
    addFolderToZip(path, srcFile, zip, destZipFile);
} else if (!srcFile.getName().equals(destZipFile)) {
    byte[] buf = new byte[1024];
    int len;
    final InputStream in = new BufferedInputStream(new FileInputStream(srcFile));
    try {
        if (path.equals("/")) {
...

File folder = new File(srcFile);
if (folder.isDirectory()) {
    addFolderToZip(path, srcFile, zip, false);
} else {
    byte[] buf = new byte[1024];
    int len;
    FileInputStream in = new FileInputStream(srcFile);
    try {
...

File folder = new File(srcFile);
if (folder.isDirectory()) {
    addFolderToZip(path, srcFile, zip);
} else {
    byte[] buf = new byte[1024];
    int len;
    FileInputStream in = new FileInputStream(srcFile);
    zip.putNextEntry(new ZipEntry(path + "/" + folder.getName()));
...

byte[] buf = new byte[1024]; 
ZipEntry ze = new ZipEntry(entry);
try {
    out.putNextEntry(ze);
    int len;
    while ((len = in.read(buf)) > 0) {
        out.write(buf, 0, len);
    in.close();
    out.closeEntry();
} catch (Exception e) {
    e.printStackTrace();

String relativeFilename = file.getCanonicalPath().substring(basePath.length() + 1,
        file.getCanonicalPath().length());
ZipEntry zipEntry = new ZipEntry(relativeFilename);
zipOutputStream.putNextEntry(zipEntry);
try (FileInputStream fileInputStream = new FileInputStream(file);) {
    byte[] inputBuffer = new byte[1024];
    int bytesRead;
    while ((bytesRead = fileInputStream.read(inputBuffer)) != -1) {
...

zipOutputStream.putNextEntry(new ZipEntry(path));
zipOutputStream.write(bytes, 0, bytes.length);
zipOutputStream.closeEntry();

if (file.isFile()) {
    File relativeFile = new File(file.getAbsolutePath().substring(rootDir.getPath().length() + 1));
    ZipEntry ze = new ZipEntry(relativeFile.getPath());
    zos.putNextEntry(ze);
    int count;
    byte data[] = new byte[BUF_SIZE];
    BufferedInputStream origin = new BufferedInputStream(new FileInputStream(file));
    while ((count = origin.read(data, 0, BUF_SIZE)) != -1) {
...

String fileName = file.getName();
try (FileInputStream fos = new FileInputStream(file)) {
    ZipEntry zipEntry = new ZipEntry(fileName);
    zipEntry.setSize(file.length());
    zipEntry.setTime(System.currentTimeMillis());
    zipOs.putNextEntry(zipEntry);
    byte[] buf = new byte[1024];
    int bytesRead;
...