java.io.FileNotFoundException#initCause ( )源码实例Demo

public java.io.InputStream getInputStream () throws java.io.FileNotFoundException {
    if (openStreams < 0) {
        FileNotFoundException e = new FileNotFoundException("Already exists output stream");
        if (previousStream != null) {
            e.initCause(previousStream);
        }
        throw e;
    }
    
    class IS extends ByteArrayInputStream {
        public IS(byte[] arr) {
            super(arr);
            openStreams++;
        }

        @Override
        public void close() throws IOException {
            openStreams--;
            super.close();
        }
    }
    previousStream = new Exception("Input");
    
    return new IS(RUNNING.content.getBytes ());
}
 

public java.io.InputStream getInputStream () throws java.io.FileNotFoundException {
    if (openStreams < 0) {
        FileNotFoundException e = new FileNotFoundException("Already exists output stream");
        if (previousStream != null) {
            e.initCause(previousStream);
        }
        throw e;
    }
    
    class IS extends ByteArrayInputStream {
        public IS(byte[] arr) {
            super(arr);
            openStreams++;
        }

        @Override
        public void close() throws IOException {
            openStreams--;
            super.close();
        }
    }
    previousStream = new Exception("Input");
    
    return new IS(RUNNING.content.getBytes ());
}
 

@Override
   public LocalFilesystemURL[] listChildren(LocalFilesystemURL inputURL) throws FileNotFoundException {
       String pathNoSlashes = inputURL.path.substring(1);
       if (pathNoSlashes.endsWith("/")) {
           pathNoSlashes = pathNoSlashes.substring(0, pathNoSlashes.length() - 1);
       }

       String[] files;
       try {
           files = listAssets(pathNoSlashes);
       } catch (IOException e) {
           FileNotFoundException fnfe = new FileNotFoundException();
           fnfe.initCause(e);
           throw fnfe;
       }

       LocalFilesystemURL[] entries = new LocalFilesystemURL[files.length];
       for (int i = 0; i < files.length; ++i) {
           entries[i] = localUrlforFullPath(new File(inputURL.path, files[i]).getPath());
       }
       return entries;
}
 

@Override
   public LocalFilesystemURL[] listChildren(LocalFilesystemURL inputURL) throws FileNotFoundException {
       String pathNoSlashes = inputURL.path.substring(1);
       if (pathNoSlashes.endsWith("/")) {
           pathNoSlashes = pathNoSlashes.substring(0, pathNoSlashes.length() - 1);
       }

       String[] files;
       try {
           files = listAssets(pathNoSlashes);
       } catch (IOException e) {
           FileNotFoundException fnfe = new FileNotFoundException();
           fnfe.initCause(e);
           throw fnfe;
       }

       LocalFilesystemURL[] entries = new LocalFilesystemURL[files.length];
       for (int i = 0; i < files.length; ++i) {
           entries[i] = localUrlforFullPath(new File(inputURL.path, files[i]).getPath());
       }
       return entries;
}
 

@Override
   public LocalFilesystemURL[] listChildren(LocalFilesystemURL inputURL) throws FileNotFoundException {
       String pathNoSlashes = inputURL.path.substring(1);
       if (pathNoSlashes.endsWith("/")) {
           pathNoSlashes = pathNoSlashes.substring(0, pathNoSlashes.length() - 1);
       }

       String[] files;
       try {
           files = listAssets(pathNoSlashes);
       } catch (IOException e) {
           FileNotFoundException fnfe = new FileNotFoundException();
           fnfe.initCause(e);
           throw fnfe;
       }

       LocalFilesystemURL[] entries = new LocalFilesystemURL[files.length];
       for (int i = 0; i < files.length; ++i) {
           entries[i] = localUrlforFullPath(new File(inputURL.path, files[i]).getPath());
       }
       return entries;
}
 

/**
 * java.io only throws FileNotFoundException when opening files, regardless of what actually
 * went wrong. Additionally, java.io is more restrictive than POSIX when it comes to opening
 * directories: POSIX says read-only is okay, but java.io doesn't even allow that. We also
 * have an Android-specific hack to alter the default permissions.
 */
public static FileDescriptor open(String path, int flags) throws FileNotFoundException {
    FileDescriptor fd = null;
    try {
        // On Android, we don't want default permissions to allow global access.
        int mode = ((flags & O_ACCMODE) == O_RDONLY) ? 0 : 0600;
        fd = Libcore.os.open(path, flags, mode);
        // Posix open(2) fails with EISDIR only if you ask for write permission.
        // Java disallows reading directories too.
        if (isDirectory(path)) {
            throw new ErrnoException("open", EISDIR);
        }
        return fd;
    } catch (ErrnoException errnoException) {
        try {
            if (fd != null) {
                IoUtils.close(fd);
            }
        } catch (IOException ignored) {
        }
        FileNotFoundException ex = new FileNotFoundException(path + ": " + errnoException.getMessage());
        ex.initCause(errnoException);
        throw ex;
    }
}
 

private void waitForFetch() throws IOException, InterruptedException {
  Preconditions.checkState(pendingFetch != null, "%s: no fetch pending", this);
  Preconditions.checkState(!current.hasRemaining(), "%s: current has remaining", this);
  try {
    GcsFileMetadata gcsFileMetadata = pendingFetch.get();
    flipToNextBlockAndPrefetch(gcsFileMetadata.getLength());
  } catch (ExecutionException e) {
    if (e.getCause() instanceof BadRangeException) {
      eofHit = true;
      current = EMPTY_BUFFER;
      next = null;
      pendingFetch = null;
    } else if (e.getCause() instanceof FileNotFoundException) {
      FileNotFoundException toThrow = new FileNotFoundException(e.getMessage());
      toThrow.initCause(e);
      throw toThrow;
    } else if (e.getCause() instanceof IOException) {
      log.log(Level.WARNING, this + ": IOException fetching block", e);
      requestBlock();
      throw new IOException(this + ": Prefetch failed, prefetching again", e.getCause());
    } else {
      throw new RuntimeException(this + ": Unknown cause of ExecutionException", e.getCause());
    }
  }
}
 

public static OutputStream getOutputStream(Object target) throws IOException {
	if (target instanceof OutputStream) {
		return (OutputStream) target;
	} 
	if (target instanceof String) {
		String filename=(String)target;
		if (StringUtils.isEmpty(filename)) {
			throw new IOException("target string cannot be empty but must contain a filename");
		}
		try {
			return new FileOutputStream(filename);
		} catch (FileNotFoundException e) {
			FileNotFoundException fnfe = new FileNotFoundException("cannot create file ["+filename+"]");
			fnfe.initCause(e);
			throw fnfe;					
		}
	}
	return null;
}
 

public static FileNotFoundException asFileNotFoundException(Throwable t)
        throws FileNotFoundException {
    if (t instanceof FileNotFoundException) {
        throw (FileNotFoundException) t;
    }
    final FileNotFoundException fnfe = new FileNotFoundException(t.getMessage());
    fnfe.initCause(t);
    throw fnfe;
}
 

public static FileNotFoundException asFileNotFoundException(Throwable t)
        throws FileNotFoundException {
    if (t instanceof FileNotFoundException) {
        throw (FileNotFoundException) t;
    }
    final FileNotFoundException fnfe = new FileNotFoundException(t.getMessage());
    fnfe.initCause(t);
    throw fnfe;
}
 

public static FileNotFoundException asFileNotFoundException(Throwable t)
        throws FileNotFoundException {
    if (t instanceof FileNotFoundException) {
        throw (FileNotFoundException) t;
    }
    final FileNotFoundException fnfe = new FileNotFoundException(t.getMessage());
    fnfe.initCause(t);
    throw fnfe;
}
 

protected static FileNotFoundException initFileNotFoundException(IPath path, Throwable cause)
{
	FileNotFoundException e = new FileNotFoundException(path.toPortableString());
	if (cause != null)
	{
		e.initCause(cause);
	}
	return e;
}
 

/** Creates FileNotFoundException with suitable message for a GCS bucket or object. */
public static FileNotFoundException createFileNotFoundException(
    String bucketName, String objectName, @Nullable IOException cause) {
  checkArgument(!isNullOrEmpty(bucketName), "bucketName must not be null or empty");
  FileNotFoundException fileNotFoundException =
      new FileNotFoundException(
          String.format(
              "Item not found: '%s'. Note, it is possible that the live version"
                  + " is still available but the requested generation is deleted.",
              StringPaths.fromComponents(bucketName, nullToEmpty(objectName))));
  if (cause != null) {
    fileNotFoundException.initCause(cause);
  }
  return fileNotFoundException;
}
 

/**
 * Tests {@link Exceptions#formatChainedMessages(Locale, String, Throwable)}.
 */
@Test
public void testFormatChainedMessages() {
    final String lineSeparator = System.lineSeparator();
    final FileNotFoundException cause = new FileNotFoundException("MisingFile.txt");
    cause.initCause(new IOException("Disk is not mounted."));
    final Exception e = new Exception("Can not find “MisingFile.txt”.", cause);
    /*
     * The actual sequence of messages (with their cause is):
     *
     *    Can not find “MisingFile.txt”
     *    MisingFile.txt
     *    Disk is not mounted.
     *
     * But the second line shall be omitted because it duplicates the first line.
     */
    String message = Exceptions.formatChainedMessages(Locale.ENGLISH, null, e);
    assertEquals("Can not find “MisingFile.txt”." + lineSeparator +
                 "Caused by IOException: Disk is not mounted.",
                 message);
    /*
     * Test again with a header.
     */
    message = Exceptions.formatChainedMessages(Locale.ENGLISH, "Error while creating the data store.", e);
    assertEquals("Error while creating the data store." + lineSeparator +
                 "Caused by Exception: Can not find “MisingFile.txt”." + lineSeparator +
                 "Caused by IOException: Disk is not mounted.",
                 message);
}
 

private static void throwFileNotFoundException(final String name,
        final Throwable t) throws FileNotFoundException {
    final FileNotFoundException e = new FileNotFoundException(
            "No file, resource or URL found: " + name);
    if (t != null) {
        e.initCause(t);
    }
    throw e;
}