IOUtils.closeQuietly：在finally中关掉流时不用再catch一遍IOException版权声明

在使用 stream 当，经常 try catch IOException。eric教我关掉小溪 finally 写入和写入 close 在判断是否存在之前 null。但是 stream.close() 也会 throw IOException这导致 finally 中 也需要 try catch 所以代码很长。如下：

byte[] data = new byte[1024];
InputStream in = null;
OutputStream out = null;

try {
in = new FileInputStream("foo.txt");
in.read(data);

out = new FileOutputStream("foo.txt");
data = "Hello, World".getBytes();
out.write(data);

IOUtils.copy(in, out);

} catch (IOException e) {
// error handling
} finally {
if (in != null) {
try {
in.close();
} catch (IOException e) {
LOGGER.warn("Fail to close stream : ", e);
}
}
if (out != null) {
try {
out.close();
} catch (IOException e) {
LOGGER.warn("Fail to close stream : ", e);
}
}
}
你可以在这个时候使用它。 IOUtils.closeQuietly 要简化代码，请执行以下操作：

byte[] data = new byte[1024];
InputStream in = null;
OutputStream out = null;

try {
in = new FileInputStream("foo.txt");
in.read(data);

out = new FileOutputStream("foo.txt");
data = "Hello, World".getBytes();
out.write(data);

IOUtils.copy(in, out);

in.close(); //close errors are handled
out.close();
} catch (IOException e) {
// error handling
} finally {
IOUtils.closeQuietly(in);
IOUtils.closeQuietly(out);
}
closeQuietly 的内部实现如下：

/**

• Closes an Reader unconditionally.
• Equivalent to {@link Reader#close()}, except any exceptions will be ignored.
• This is typically used in finally blocks.
• Example code:
•   char[] data = new char[1024];
•   Reader in = null;
•   try {
•       in = new FileReader("foo.txt");
•       in.read(data);
•       in.close(); //close errors are handled
•   } catch (Exception e) {
•       // error handling
•   } finally {
•       IOUtils.closeQuietly(in);
•   }
• @param input the Reader to close, may be null or already closed
  */
  public static void closeQuietly(final Reader input) {
  closeQuietly((Closeable) input);
  }

/**

• Closes an Writer unconditionally.
• Equivalent to {@link Writer#close()}, except any exceptions will be ignored.
• This is typically used in finally blocks.
• Example code:
•   Writer out = null;
•   try {
•       out = new StringWriter();
•       out.write("Hello World");
•       out.close(); //close errors are handled
•   } catch (Exception e) {
•       // error handling
•   } finally {
•       IOUtils.closeQuietly(out);
•   }
• @param output the Writer to close, may be null or already closed
  */
  public static void closeQuietly(final Writer output) {
  closeQuietly((Closeable) output);
  }

/**

• Closes an InputStream unconditionally.
• Equivalent to {@link InputStream#close()}, except any exceptions will be ignored.
• This is typically used in finally blocks.
• Example code:
•   byte[] data = new byte[1024];
•   InputStream in = null;
•   try {
•       in = new FileInputStream("foo.txt");
•       in.read(data);
•       in.close(); //close errors are handled
•   } catch (Exception e) {
•       // error handling
•   } finally {
•       IOUtils.closeQuietly(in);
•   }
• @param input the InputStream to close, may be null or already closed
  */
  public static void closeQuietly(final InputStream input) {
  closeQuietly((Closeable) input);
  }

/**

• Closes an OutputStream unconditionally.
• Equivalent to {@link OutputStream#close()}, except any exceptions will be ignored.
• This is typically used in finally blocks.
• Example code:
• byte[] data = "Hello, World".getBytes();
• OutputStream out = null;
• try {
•     out = new FileOutputStream("foo.txt");
•     out.write(data);
•     out.close(); //close errors are handled
• } catch (IOException e) {
•     // error handling
• } finally {
•     IOUtils.closeQuietly(out);
• }
• @param output the OutputStream to close, may be null or already closed
  */
  public static void closeQuietly(final OutputStream output) {
  closeQuietly((Closeable) output);
  }

/**

• Closes a Closeable unconditionally.
• Equivalent to {@link Closeable#close()}, except any exceptions will be ignored. This is typically used in
• finally blocks.
• Example code:
• Closeable closeable = null;
• try {
•     closeable = new FileReader("foo.txt");
•     // process closeable
•     closeable.close();
• } catch (Exception e) {
•     // error handling
• } finally {
•     IOUtils.closeQuietly(closeable);
• }
• Closing all streams:
• try {
•     return IOUtils.copy(inputStream, outputStream);
• } finally {
•     IOUtils.closeQuietly(inputStream);
•     IOUtils.closeQuietly(outputStream);
• }
• @param closeable the objects to close, may be null or already closed
• @since 2.0
  */
  public static void closeQuietly(final Closeable closeable) {
  try {
  if (closeable != null) {
  closeable.close();
  }
  } catch (final IOException ioe) {
  // ignore
  }
  }

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  作者：huanghanqian
  来源：CSDN
  原文：https://blog.csdn.net/huanghanqian/article/details/82500132
  版权声明：本文为博主原创文章，转载请附上博客链接！