IOUtils.java

/*
 * Licensed to the Apache Software Foundation (ASF) under one
 * or more contributor license agreements.  See the NOTICE file
 * distributed with this work for additional information
 * regarding copyright ownership.  The ASF licenses this file
 * to you under the Apache License, Version 2.0 (the
 * "License"); you may not use this file except in compliance
 * with the License.  You may obtain a copy of the License at
 *
 *     http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing,
 * software distributed under the License is distributed on an
 * "AS IS" BASIS, WITHOUT WARRANTIES OR CONDITIONS OF ANY
 * KIND, either express or implied.  See the License for the
 * specific language governing permissions and limitations
 * under the License.
 */

package com.aliyun.odps.commons.util;

import java.io.ByteArrayOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;

/**
 * IO Utils
 */
public class IOUtils {

  public static final int READ_BUFFER_SIZE = 4096;

  private static final int EOF = -1;

  /**
   * Read fully from the InputStream
   *
   * @param in
   * @return
   * @throws IOException
   */
  public static byte[] readFully(InputStream in) throws IOException {
    try {
      byte[] buf = new byte[READ_BUFFER_SIZE];
      int read = -1;
      ByteArrayOutputStream os = new ByteArrayOutputStream();
      while ((read = in.read(buf)) != -1) {
        os.write(buf, 0, read);
      }
      os.close();
      return os.toByteArray();
    } finally {
      if (in != null) {
        in.close();
      }
    }
  }

  /**
   * Get InputStream bytes count without reading
   *
   * @param in
   * @return
   * @throws IOException
   */
  public static long getInputStreamLength(InputStream in) throws IOException {
    if (in instanceof FileInputStream) {
      return ((FileInputStream) in).getChannel().size();
    }
    return in.available();
  }

  /**
   * Reset the InputStream to the beginning/mark position without a large buffer
   *
   * @param in
   * @throws IOException
   */
  public static void resetInputStream(InputStream in) throws IOException {
    if (in.markSupported()) {
      in.reset();
    }
    if (in instanceof FileInputStream) {
      ((FileInputStream) in).getChannel().position(0);
    }
  }

  /**
   * Copy bytes from a large (over 2GB) <code>InputStream</code> to an
   * <code>OutputStream</code>.
   * <p>
   * This method buffers the input internally, so there is no need to use a
   * <code>BufferedInputStream</code>.
   * <p>
   * The buffer size is given by {@link #DEFAULT_BUFFER_SIZE}.
   *
   * @param input
   *     the <code>InputStream</code> to read from
   * @param output
   *     the <code>OutputStream</code> to write to
   * @return the number of bytes copied
   * @throws NullPointerException
   *     if the input or output is null
   * @throws IOException
   *     if an I/O error occurs
   * @since Shamelessly cloned from Apache Commons IO 1.3 IOUtils
   */
  public static long copyLarge(InputStream input, OutputStream output) throws IOException {
    return copyLarge(input, output, new byte[READ_BUFFER_SIZE]);
  }

  /**
   * Copy bytes from a large (over 2GB) <code>InputStream</code> to an
   * <code>OutputStream</code>.
   * <p>
   * This method uses the provided buffer, so there is no need to use a
   * <code>BufferedInputStream</code>.
   * <p>
   *
   * @param input
   *     the <code>InputStream</code> to read from
   * @param output
   *     the <code>OutputStream</code> to write to
   * @param buffer
   *     the buffer to use for the copy
   * @return the number of bytes copied
   * @throws NullPointerException
   *     if the input or output is null
   * @throws IOException
   *     if an I/O error occurs
   * @since Shamelessly cloned from Apache Commons IO 2.2 IOUtils
   */
  public static long copyLarge(InputStream input, OutputStream output, byte[] buffer)
      throws IOException {
    long count = 0;
    int n = 0;
    while (EOF != (n = input.read(buffer))) {
      output.write(buffer, 0, n);
      count += n;
    }
    return count;
  }

  public static String readStreamAsString(InputStream in, String charset) throws IOException {
    return new String(readFully(in), charset);
  }

  public static String readStreamAsString(InputStream in) throws IOException {
    return new String(readFully(in), "utf-8");
  }
}