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commons-IO 包解析学习---FileUtils篇（1）

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Javacommons-io 
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由于Android项目忙完，苦于学习方向迷失，决定开一个进度，学习解析commons-IO包，提高JAVA水平，学习JAVA IO部分。

 

废话不多说，进入正题。

 

1.

 

//-----------------------------------------------------------------------
    /**
     * Compares the contents of two files to determine if they are equal or not.
     * <p>
     * This method checks to see if the two files are different lengths
     * or if they point to the same file, before resorting to byte-by-byte
     * comparison of the contents.
     * <p>
     * Code origin: Avalon
     *
     * @param file1  the first file
     * @param file2  the second file
     * @return true if the content of the files are equal or they both don't
     * exist, false otherwise
     * @throws IOException in case of an I/O error
     */
    public static boolean contentEquals(File file1, File file2) throws IOException {
        boolean file1Exists = file1.exists();
        if (file1Exists != file2.exists()) {
            return false;
        }

        if (!file1Exists) {
            // two not existing files are equal
            return true;
        }

        if (file1.isDirectory() || file2.isDirectory()) {
            // don't want to compare directory contents
            throw new IOException("Can't compare directories, only files");
        }

        if (file1.length() != file2.length()) {
            // lengths differ, cannot be equal
            return false;
        }

        if (file1.getCanonicalFile().equals(file2.getCanonicalFile())) {
            // same file
            return true;
        }

        InputStream input1 = null;
        InputStream input2 = null;
        try {
            input1 = new FileInputStream(file1);
            input2 = new FileInputStream(file2);
            return IOUtils.contentEquals(input1, input2);

        } finally {
            IOUtils.closeQuietly(input1);
            IOUtils.closeQuietly(input2);
        }
    }

这个函数用来比较两个file里面的文件是否相同。

 

比较策略：

1.判断是否有一个存在一个不存在（两个不存在也算相同）

2.判断两个是不是至少一个是目录（不能比较目录内容）

3.判断两个文件的长度是否相同，不同则返回false

4.应用File.getCanonicalFile()这个函数返回文件路径判断是不是指向同一个文件

5.最后才用inputstream导入两个文件，使用IOUtils.contentEquals(input1, input2)判断内容是否相等

 

2.

 

    /**
     * Compares the contents of two files to determine if they are equal or not.
     * <p>
     * This method checks to see if the two files point to the same file, 
     * before resorting to line-by-line comparison of the contents.
     * <p>
     *
     * @param file1  the first file
     * @param file2  the second file
     * @param charsetName the character encoding to be used. 
     *        May be null, in which case the platform default is used
     * @return true if the content of the files are equal or neither exists,
     *         false otherwise
     * @throws IOException in case of an I/O error
     * @since 2.2
     * @see IOUtils#contentEqualsIgnoreEOL(Reader, Reader)
     */
    public static boolean contentEqualsIgnoreEOL(File file1, File file2, String charsetName) throws IOException {
        boolean file1Exists = file1.exists();
        if (file1Exists != file2.exists()) {
            return false;
        }

        if (!file1Exists) {
            // two not existing files are equal
            return true;
        }

        if (file1.isDirectory() || file2.isDirectory()) {
            // don't want to compare directory contents
            throw new IOException("Can't compare directories, only files");
        }

        if (file1.getCanonicalFile().equals(file2.getCanonicalFile())) {
            // same file
            return true;
        }

        Reader input1 = null;
        Reader input2 = null;
        try {
            if (charsetName == null) {
                input1 = new InputStreamReader(new FileInputStream(file1));
                input2 = new InputStreamReader(new FileInputStream(file2));
            } else {
                input1 = new InputStreamReader(new FileInputStream(file1), charsetName);
                input2 = new InputStreamReader(new FileInputStream(file2), charsetName);
            }
            return IOUtils.contentEqualsIgnoreEOL(input1, input2);

        } finally {
            IOUtils.closeQuietly(input1);
            IOUtils.closeQuietly(input2);
        }
    }


本函数和上一条基本相同，区别在于：

 

 

        Reader input1 = null;
        Reader input2 = null;
        try {
            if (charsetName == null) {
                input1 = new InputStreamReader(new FileInputStream(file1));
                input2 = new InputStreamReader(new FileInputStream(file2));
            } else {
                input1 = new InputStreamReader(new FileInputStream(file1), charsetName);
                input2 = new InputStreamReader(new FileInputStream(file2), charsetName);
            }
            return IOUtils.contentEqualsIgnoreEOL(input1, input2);

        } finally {
            IOUtils.closeQuietly(input1);
            IOUtils.closeQuietly(input2);
        }


这里使用了charsetName，用以获取编码后的字符流

 

*学习：

InputStreamReader的创建（使用charsetName参数编码FileInputStream获取的字节）

 

 

 

 

3.

 

public static File toFile(URL url) {
        if (url == null || !"file".equalsIgnoreCase(url.getProtocol())) {
            return null;
        } else {
            String filename = url.getFile().replace('/', File.separatorChar);
            filename = decodeUrl(filename);
            return new File(filename);
        }
    }


一个用于把file协议的url转换为File类型的函数

 

 

4.

 

static String decodeUrl(String url) {
        String decoded = url;
        if (url != null && url.indexOf('%') >= 0) {
            int n = url.length();
            StringBuffer buffer = new StringBuffer();
            ByteBuffer bytes = ByteBuffer.allocate(n);
            for (int i = 0; i < n;) {
                if (url.charAt(i) == '%') {
                    try {
                        do {
                            byte octet = (byte) Integer.parseInt(url.substring(i + 1, i + 3), 16);
                            bytes.put(octet);
                            i += 3;
                        } while (i < n && url.charAt(i) == '%');
                        continue;
                    } catch (RuntimeException e) {
                        // malformed percent-encoded octet, fall through and
                        // append characters literally
                    } finally {
                        if (bytes.position() > 0) {
                            bytes.flip();
                            buffer.append(UTF8.decode(bytes).toString());
                            bytes.clear();
                        }
                    }
                }
                buffer.append(url.charAt(i++));
            }
            decoded = buffer.toString();
        }
        return decoded;
    }


转换URL出现问题时的优化处理

 

（存疑）

 

 

5.

 

public static File[] toFiles(URL[] urls) {
        if (urls == null || urls.length == 0) {
            return EMPTY_FILE_ARRAY;
        }
        File[] files = new File[urls.length];
        for (int i = 0; i < urls.length; i++) {
            URL url = urls[i];
            if (url != null) {
                if (url.getProtocol().equals("file") == false) {
                    throw new IllegalArgumentException(
                            "URL could not be converted to a File: " + url);
                }
                files[i] = toFile(url);
            }
        }
        return files;
    }


Converts each of an array of URL to a File.

 

刚才函数toFile()的数组版本

 

6.

 

public static URL[] toURLs(File[] files) throws IOException {
        URL[] urls = new URL[files.length];

        for (int i = 0; i < urls.length; i++) {
            urls[i] = files[i].toURI().toURL();
        }

        return urls;
    }


Converts each of an array of File to a URL.

 

 

7.

 

public static void copyFileToDirectory(File srcFile, File destDir) throws IOException {
        copyFileToDirectory(srcFile, destDir, true);
    }


Copies a file to a directory preserving the file date.

 

 

8.

 

public static void copyFileToDirectory(File srcFile, File destDir, boolean preserveFileDate) throws IOException {
        if (destDir == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (destDir.exists() && destDir.isDirectory() == false) {
            throw new IllegalArgumentException("Destination '" + destDir + "' is not a directory");
        }
        File destFile = new File(destDir, srcFile.getName());
        copyFile(srcFile, destFile, preserveFileDate);
    }


刚才函数7的完整版本：

 

1.确保目标地址不是空的

2.确保目标地址存在，并且不是文件

3.对源文件和目标文件的保护在copyFile里做了，所以这里只做对目标目录的保护。

 

 

9.

 

public static void copyFile(File srcFile, File destFile) throws IOException {
        copyFile(srcFile, destFile, true);
    }

 

 

包装函数，重载默认保存date

 

10.

 

    public static void copyFile(File srcFile, File destFile,
            boolean preserveFileDate) throws IOException {
        if (srcFile == null) {
            throw new NullPointerException("Source must not be null");
        }
        if (destFile == null) {
            throw new NullPointerException("Destination must not be null");
        }
        if (srcFile.exists() == false) {
            throw new FileNotFoundException("Source '" + srcFile + "' does not exist");
        }
        if (srcFile.isDirectory()) {
            throw new IOException("Source '" + srcFile + "' exists but is a directory");
        }
        if (srcFile.getCanonicalPath().equals(destFile.getCanonicalPath())) {
            throw new IOException("Source '" + srcFile + "' and destination '" + destFile + "' are the same");
        }
        File parentFile = destFile.getParentFile();
        if (parentFile != null) {
            if (!parentFile.mkdirs() && !parentFile.isDirectory()) {
                throw new IOException("Destination '" + parentFile + "' directory cannot be created");
            }
        }
        if (destFile.exists() && destFile.canWrite() == false) {
            throw new IOException("Destination '" + destFile + "' exists but is read-only");
        }
        doCopyFile(srcFile, destFile, preserveFileDate);
    }


策略学习：

 

目标文件和源文件的保护监测

 

11.

 

public static long copyFile(File input, OutputStream output) throws IOException {
        final FileInputStream fis = new FileInputStream(input);
        try {
            return IOUtils.copyLarge(fis, output);
        } finally {
            fis.close();
        }
    }


从一个input文件中拷贝bytes进入output输出流，注意：

 

IOUtils.copyLarge(fis, output)这个方法内部使用了buffer，所以不需要使用BufferedInputStream

 

12.

 

    private static void doCopyFile(File srcFile, File destFile, boolean preserveFileDate) throws IOException {
        if (destFile.exists() && destFile.isDirectory()) {
            throw new IOException("Destination '" + destFile + "' exists but is a directory");
        }

        FileInputStream fis = null;
        FileOutputStream fos = null;
        FileChannel input = null;
        FileChannel output = null;
        try {
            fis = new FileInputStream(srcFile);
            fos = new FileOutputStream(destFile);
            input  = fis.getChannel();
            output = fos.getChannel();
            long size = input.size();
            long pos = 0;
            long count = 0;
            while (pos < size) {
                count = size - pos > FILE_COPY_BUFFER_SIZE ? FILE_COPY_BUFFER_SIZE : size - pos;
                pos += output.transferFrom(input, pos, count);
            }
        } finally {
            IOUtils.closeQuietly(output);
            IOUtils.closeQuietly(fos);
            IOUtils.closeQuietly(input);
            IOUtils.closeQuietly(fis);
        }

        if (srcFile.length() != destFile.length()) {
            throw new IOException("Failed to copy full contents from '" +
                    srcFile + "' to '" + destFile + "'");
        }
        if (preserveFileDate) {
            destFile.setLastModified(srcFile.lastModified());
        }
    }


使用nio中的FileChannel进行复制（传输文件内容），调用IOUtils.closeQuietly()关闭filechannel和I/Ostream

 

最后用文件的length长度监测是否传输成功

 

 

16.
publicstaticvoidcopyDirectory(File srcDir, File destDir,
FileFilter filter,booleanpreserveFileDate)throwsIOException {
if(srcDir ==null) {
thrownewNullPointerException("Source must not be null");
}
if(destDir ==null) {
thrownewNullPointerException("Destination must not be null");
}
if(srcDir.exists() ==false) {
thrownewFileNotFoundException("Source '"+ srcDir +"' does not exist");
}
if(srcDir.isDirectory() ==false) {
thrownewIOException("Source '"+ srcDir +"' exists but is not a directory");
}
if(srcDir.getCanonicalPath().equals(destDir.getCanonicalPath())) {
thrownewIOException("Source '"+ srcDir +"' and destination '"+ destDir +"' are the same");
}
 
// Cater for destination being directory within the source directory (see IO-141)
List<String> exclusionList =null;
if(destDir.getCanonicalPath().startsWith(srcDir.getCanonicalPath())) {
File[] srcFiles = filter ==null? srcDir.listFiles() : srcDir.listFiles(filter);
if(srcFiles !=null&& srcFiles.length> 0) {
exclusionList =newArrayList<String>(srcFiles.length);
for(File srcFile : srcFiles) {
File copiedFile =newFile(destDir, srcFile.getName());
exclusionList.add(copiedFile.getCanonicalPath());
}
}
}
doCopyDirectory(srcDir, destDir, filter, preserveFileDate, exclusionList);
}
 
 
 
这个函数加入了一个filter对复制操作的file加以过滤
 
注意：这里有一个假如destDir是srcDir的子目录的附加操作
// Cater for destination being directory within the source directory (see IO-141)
List<String> exclusionList =null;
if(destDir.getCanonicalPath().startsWith(srcDir.getCanonicalPath())) {
File[] srcFiles = filter ==null? srcDir.listFiles() : srcDir.listFiles(filter);
if(srcFiles !=null&& srcFiles.length> 0) {
exclusionList =newArrayList<String>(srcFiles.length);
for(File srcFile : srcFiles) {
File copiedFile =newFile(destDir, srcFile.getName());
exclusionList.add(copiedFile.getCanonicalPath());
}
}
}
 
exclusionList是要排除的文件路径String列表（因为本来就在desDir里面），要作为参数传入下一个docopy()方法中
 
 
17.
privatestaticvoiddoCopyDirectory(FilesrcDir, File destDir, FileFilter filter,
booleanpreserveFileDate, List<String> exclusionList)throwsIOException {
// recurse
File[] srcFiles = filter ==null?srcDir.listFiles() :srcDir.listFiles(filter);
if(srcFiles ==null) {// null if abstract pathname does not denote a directory, or if an I/O error occurs
thrownewIOException("Failed to list contents of "+srcDir);
}
if(destDir.exists()) {
if(destDir.isDirectory() ==false) {
thrownewIOException("Destination '"+ destDir +"' exists but is not a directory");
}
}else{
if(!destDir.mkdirs() && !destDir.isDirectory()) {
thrownewIOException("Destination '"+ destDir +"' directory cannot be created");
}
}
if(destDir.canWrite() ==false) {
thrownewIOException("Destination '"+ destDir +"' cannot be written to");
}
for(File srcFile : srcFiles) {
File dstFile =newFile(destDir, srcFile.getName());
if(exclusionList ==null|| !exclusionList.contains(srcFile.getCanonicalPath())) {
if(srcFile.isDirectory()) {
doCopyDirectory(srcFile, dstFile, filter, preserveFileDate, exclusionList);
}else{
doCopyFile(srcFile, dstFile, preserveFileDate);
}
}
}
 
// Do this last, as the above has probably affected directory metadata
if(preserveFileDate) {
destDir.setLastModified(srcDir.lastModified());
}
}
 
 
注意：
1.递归调用，反复打开子目录复制文件
2.排除列表的操作
 
 
20.
publicstaticvoidcopyInputStreamToFile(InputStream source, File destination)throwsIOException {
try{
FileOutputStream output =openOutputStream(destination);
try{
IOUtils.copy(source, output);
output.close();// don't swallow close Exception if copy completes normally
}finally{
IOUtils.closeQuietly(output);
}
}finally{
IOUtils.closeQuietly(source);
}
}
 
使用IOUtils.copy()函数复制source流到output流（目标文件输出流）
 
 
21.
publicstaticvoiddeleteDirectory(File directory)throwsIOException {
if(!directory.exists()) {
return;
}
 
if(!isSymlink(directory)) {
cleanDirectory(directory);
}
 
if(!directory.delete()) {
String message =
"Unable to delete directory "+ directory +".";
thrownewIOException(message);
}
}
 
 
isSymlink(directory)貌似和windows没关系？？暂时存疑
调用cleanDirectory清空目录，然后删除目录本身
 
 
22.
publicstaticbooleandeleteQuietly(File file) {
if(file ==null) {
returnfalse;
}
try{
if(file.isDirectory()) {
cleanDirectory(file);
}
}catch(Exception ignored) {
}
 
try{
returnfile.delete();
}catch(Exception ignored) {
returnfalse;
}
}
 
本身Doc的描述：

Deletes a file, never throwing an exception. If file is a directory, delete it and all sub-directories.

The difference between File.delete() and this method are:

  • A directory to be deleted does not have to be empty. 亮点所在！！！！！！！！！
  • No exceptions are thrown when a file or directory cannot be deleted.
 
23.
publicstaticbooleandirectoryContains(finalFile directory,finalFile child)throwsIOException {
 
// Fail fast against NullPointerException
if(directory ==null) {
thrownewIllegalArgumentException("Directory must not be null");
}
 
if(!directory.isDirectory()) {
thrownewIllegalArgumentException("Not a directory: "+ directory);
}
 
if(child ==null) {
returnfalse;
}
 
if(!directory.exists() || !child.exists()) {
returnfalse;
}
 
// Canonicalize paths (normalizes relative paths)
String canonicalParent =directory.getCanonicalPath();
String canonicalChild = child.getCanonicalPath();
 
returnFilenameUtils.directoryContains(canonicalParent, canonicalChild);
}
 
 
使用了FilenameUtils.directoryContains(canonicalParent, canonicalChild)这个方法判断是否目录包含目标文件（非限定父子包含，可以是祖先后代关系）
 
 
 
24.
publicstaticvoidcleanDirectory(File directory)throwsIOException {
if(!directory.exists()) {
String message = directory +" does not exist";
thrownewIllegalArgumentException(message);
}
 
if(!directory.isDirectory()) {
String message = directory +" is not a directory";
thrownewIllegalArgumentException(message);
}
 
File[] files = directory.listFiles();
if(files ==null) {// null if security restricted
thrownewIOException("Failed to list contents of "+ directory);
}
 
IOException exception =null;
for(File file : files) {
try{
forceDelete(file);
}catch(IOException ioe) {
exception = ioe;
}
}
 
if(null!= exception) {
throwexception;
}
}
 
调用forceDelete(file);删除文件或者文件夹
注意：
IOException exception =null;
for(File file : files) {
try{
forceDelete(file);
}catch(IOException ioe) {
exception = ioe;
}
}
 
if(null!= exception) {
throwexception;
}
这里是为了可以顺利抛出异常才这样写
 
 
 
25.
publicstaticbooleanwaitFor(File file,intseconds) {
inttimeout = 0;
inttick = 0;
while(!file.exists()) {
if(tick++ >= 10) {
tick = 0;
if(timeout++ > seconds) {
returnfalse;
}
}
try{
Thread.sleep(100);
}catch(InterruptedException ignore) {
// ignore exception
}catch(Exception ex) {
break;
}
}
returntrue;
}
 
等待一定时间，反复测试是否存在吗某一文件（可用于等待用户创建某一文件）
注意：
1.采用线程sleep(100)，使得1秒可以检查10次文件是否存在
2.这里过滤sleep操作引起的InterruptedException异常，但是捕捉其他异常，发生则会break，这里个人觉得不太好，因为这样发生异常就会返回true
 
 
34.
publicstaticvoidwriteStringToFile(File file, String data, Charset encoding,booleanappend)throwsIOException {
OutputStream out =null;
try{
out =openOutputStream(file, append);
IOUtils.write(data, out, encoding);
out.close();// don't swallow close Exception if copy completes normally
}finally{
IOUtils.closeQuietly(out);
}
}
 
这里不明白的：
out.close();// don't swallow close Exception if copy completes normally
这个什么意思？
 
 
 
38.
publicstaticvoidwrite(File file, CharSequence data, Charset encoding,booleanappend)throwsIOException {
Stringstr= data ==null?null: data.toString();
writeStringToFile(file,str, encoding, append);
}
 
CharSequence接口实现类都可以使用
 
 
 
 
46.
publicstaticvoidwriteLines(File file, String encoding, Collection<?> lines, String lineEnding,booleanappend)
throwsIOException {
FileOutputStream out =null;
try{
out =openOutputStream(file, append);
finalBufferedOutputStream buffer =newBufferedOutputStream(out);
IOUtils.writeLines(lines, lineEnding, buffer, encoding);
buffer.flush();
out.close();// don't swallow close Exception if copy completes normally
}finally{
IOUtils.closeQuietly(out);
}
}
 
这里使用了IOUtils.writeLines(lines, lineEnding, buffer, encoding);写入行，并且值得注意的是，可以用lineEnding指定行分隔符
 
 
 
 
49.
publicstaticvoidforceDelete(File file)throwsIOException {
if(file.isDirectory()) {
deleteDirectory(file);
}else{
booleanfilePresent = file.exists();
if(!file.delete()) {
if(!filePresent){
thrownewFileNotFoundException("File does not exist: "+ file);
}
String message =
"Unable to delete file: "+ file;
thrownewIOException(message);
}
}
}
这里和刚才的deleteDirectory()有隐式递归调用，在目录和文件的区分处理上，假如是目录，就用deleteDirectory()继续打开，用以递归打开再调用forceDelete(),如此反复，可以做到删除所用文件
 
 
 
 
52.
privatestaticvoidcleanDirectoryOnExit(File directory)throwsIOException {
if(!directory.exists()) {
String message = directory +" does not exist";
thrownewIllegalArgumentException(message);
}
 
if(!directory.isDirectory()) {
String message = directory +" is not a directory";
thrownewIllegalArgumentException(message);
}
 
File[] files = directory.listFiles();
if(files ==null) {// null if security restricted
thrownewIOException("Failed to list contents of "+ directory);
}
 
IOException exception =null;
for(File file : files) {
try{
forceDeleteOnExit(file);
}catch(IOException ioe) {
exception = ioe;
}
}
 
if(null!= exception) {
throwexception;
}
}
 
在JVM退出时清空，目录，其中调用到了File.deleteOnExit()
 
 
53.
publicstaticvoidforceMkdir(File directory)throwsIOException {
if(directory.exists()) {
if(!directory.isDirectory()) {
String message =
"File "
+ directory
+" exists and is "
+"not a directory. Unable to create directory.";
thrownewIOException(message);
}
}else{
if(!directory.mkdirs()) {
// Double-check that some other thread or process hasn't made
// the directory in the background
if(!directory.isDirectory())
{
String message =
"Unable to create directory "+ directory;
thrownewIOException(message);
}
}
}
}
 
存疑：
// Double-check that some other thread or process hasn't made
// the directory in the background
这是表达什么？
 
 
54.
publicstaticlongsizeOf(File file) {
 
if(!file.exists()) {
String message = file +" does not exist";
thrownewIllegalArgumentException(message);
}
 
if(file.isDirectory()) {
returnsizeOfDirectory(file);
}else{
returnfile.length();
}
 
}
 
返回一个File对象的byte大小，目录会递归调用，但是不会处理受限制的子目录
 
 
65.
publicstaticlongchecksumCRC32(File file)throwsIOException {
CRC32crc =newCRC32();
checksum(file, crc);
returncrc.getValue();
}
 
存疑
CRC32是啥？
 
66.
publicstaticChecksum checksum(File file, Checksum checksum)throwsIOException {
if(file.isDirectory()) {
thrownewIllegalArgumentException("Checksums can't be computed on directories");
}
InputStream in =null;
try{
in =newCheckedInputStream(newFileInputStream(file), checksum);
IOUtils.copy(in,newNullOutputStream());
}finally{
IOUtils.closeQuietly(in);
}
returnchecksum;
}
 
存疑
checksum是啥
 
 
 
 
67.
publicstaticvoidmoveDirectory(File srcDir, File destDir)throwsIOException {
if(srcDir ==null) {
thrownewNullPointerException("Source must not be null");
}
if(destDir ==null) {
thrownewNullPointerException("Destination must not be null");
}
if(!srcDir.exists()) {
thrownewFileNotFoundException("Source '"+ srcDir +"' does not exist");
}
if(!srcDir.isDirectory()) {
thrownewIOException("Source '"+ srcDir +"' is not a directory");
}
if(destDir.exists()) {
thrownewFileExistsException("Destination '"+ destDir +"' already exists");
}
booleanrename = srcDir.renameTo(destDir);
if(!rename) {
if(destDir.getCanonicalPath().startsWith(srcDir.getCanonicalPath())) {
thrownewIOException("Cannot move directory: "+srcDir+" to a subdirectory of itself: "+destDir);
}
copyDirectory( srcDir, destDir );
deleteDirectory( srcDir );
if(srcDir.exists()) {
thrownewIOException("Failed to delete original directory '"+ srcDir +
"' after copy to '"+ destDir +"'");
}
}
}
 
 
注意：
1.booleanrename = srcDir.renameTo(destDir);使用这个renameTo的操作移动，假如未成功再进行第二种移动操作（先复制，再删除）
2.不能移动父目录到子目录
3.删除不成功要抛出异常
 
 
 
72.
publicstaticbooleanisSymlink(File file)throwsIOException {
if(file ==null) {
thrownewNullPointerException("File must not be null");
}
if(FilenameUtils.isSystemWindows()) {
returnfalse;
}
File fileInCanonicalDir =null;
if(file.getParent() ==null) {
fileInCanonicalDir = file;
}else{
File canonicalDir = file.getParentFile().getCanonicalFile();
fileInCanonicalDir =newFile(canonicalDir, file.getName());
}
 
if(fileInCanonicalDir.getCanonicalFile().equals(fileInCanonicalDir.getAbsoluteFile())) {
returnfalse;
}else{
returntrue;
}
}
 
存疑
貌似和WINDOWS系统无关？不懂。。。

 

 

 

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