BufferedReader 到 BufferedWriter

发布于 2024-11-30 03:37:09 字数 237 浏览 0 评论 0原文

如何从 BufferedReader 获取 BufferedWriter？

我希望能够做这样的事情：

BufferedReader read  = new BufferedReader(new InputStreamReader(...));
BufferedWriter write = new BufferedWriter(read);

原文

How can I obtain a BufferedWriter from a BufferedReader?

I'd like to be able to do something like this:

BufferedReader read  = new BufferedReader(new InputStreamReader(...));
BufferedWriter write = new BufferedWriter(read);

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止于盛夏 2024-12-07 03:37:09

您可以使用 Apache commons io 中的以下内容：

IOUtils.copy(reader, writer);

站点此处

You can use the following from Apache commons io:

IOUtils.copy(reader, writer);

site here

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深海不蓝 2024-12-07 03:37:09

JAVA 9 更新

从 Java 9 开始，Reader 提供了一个名为 transferTo 的方法，其签名如下：

public long transferTo(Writer out)  throws IOException

正如文档所述，transferTo 将：

从该 reader 读取所有字符，并按顺序将字符写入给定 writer他们被阅读了。返回时，该读取器将位于流的末尾。此方法不会关闭读取器或写入器。
此方法可能会无限期地阻止读取器读取或写入写入器。读取器和/或写入器异步关闭或线程在传输期间中断的情况的行为是高度特定于读取器和写入器的，因此未指定。

如果从读取器读取或写入写入器时发生 I/O 错误，则可能会在读取或写入某些字符后发生此错误。因此，读取器可能不在流的末尾，并且一个或两个流可能处于不一致的状态。强烈建议如果发生 I/O 错误，立即关闭两个流。

因此，为了将 Java Reader 的内容写入 Writer，您可以编写：

reader.transferTo(writer);

JAVA 9 Updates

Since Java 9, Reader provides a method called transferTo with the following signature:

public long transferTo(Writer out)  throws IOException

As the documentation states, transferTo will:

Reads all characters from this reader and writes the characters to the given writer in the order that they are read. On return, this reader will be at end of the stream. This method does not close either reader or writer.
This method may block indefinitely reading from the reader, or writing to the writer. The behavior for the case where the reader and/or writer is asynchronously closed , or the thread interrupted during the transfer, is highly reader and writer specific, and therefore not specified.

If an I/O error occurs reading from the reader or writing to the writer, then it may do so after some characters have been read or written. Consequently the reader may not be at end of the stream and one, or both, streams may be in an inconsistent state. It is strongly recommended that both streams be promptly closed if an I/O error occurs.

So in order to write contents of a Java Reader to a Writer, you can write:

reader.transferTo(writer);

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予囚 2024-12-07 03:37:09

如果您想知道发生了什么：

来自阅读器的所有输入都被复制到输入流

也类似：

 private final void copyInputStream( InputStreamReader in, OutputStreamWriter out )      throws IOException
  {
    char[] buffer=new char[1024];
    int len;
    while ( ( len=in.read(buffer) ) >= 0 )
      {
      out.write(buffer, 0, len);
      }
  }

有关输入和输出的更多信息真正的大索引

If you want to know what happens:

All input from the reader is copied to the inputstream

Something similar too:

 private final void copyInputStream( InputStreamReader in, OutputStreamWriter out )      throws IOException
  {
    char[] buffer=new char[1024];
    int len;
    while ( ( len=in.read(buffer) ) >= 0 )
      {
      out.write(buffer, 0, len);
      }
  }

More on input and output on The Really big Index

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吃兔兔 2024-12-07 03:37:09

BufferedWriter 构造函数没有为接受读取器重载，对吧？布赫布说的是正确的。

BufferedWriter  writer = new BufferedWriter(
new FileWriter("filename_towrite"));    

IOUtils.copy(new InputStreamReader(new FileInputStream("filename_toread")), writer);
writer.flush();
writer.close();

BufferedWriter constructor is not overloaded for accept readers right? what Buhb said was correct.

BufferedWriter  writer = new BufferedWriter(
new FileWriter("filename_towrite"));    

IOUtils.copy(new InputStreamReader(new FileInputStream("filename_toread")), writer);
writer.flush();
writer.close();

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