缓冲器与修改输出流
有没有办法缓冲 OutputStream，在返回之前对其进行修改？这是我的代码片段：
public ServletOutputStream getOutputStream() throws IOException {
BufferedOutputStream buffer = new BufferedOutputStream(super.getOutputStream());
// Modify the buffer contents, before it is returned
return new DelegatingServletOutputStream(buffer);
}
谢谢。
is there a way to buffer a OutputStream, modify it before it is returned? Here is my code snippet:
public ServletOutputStream getOutputStream() throws IOException {
BufferedOutputStream buffer = new BufferedOutputStream(super.getOutputStream());
// Modify the buffer contents, before it is returned
return new DelegatingServletOutputStream(buffer);
}
Thanks.
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@oliholz 的答案给出了一种方法，您可以在数据“通过”过滤器流到达其目的地时对其进行修改。
另一种方法是将输出发送到 ByteArrayOutputStream ，将内容提取到字节数组，修改字节，最后将它们写入“真实”输出流。
或者您可以扩展 ByteArrayOutputStream 并重写其 close() 方法以在流关闭时执行操作...如果这就是您的意思。或者您可以覆盖
getBytes以在返回字节之前修改字节。或者重写write方法来修改正在写入的字节。您可以采用多种方法来实现它，具体取决于您的要求。@oliholz's answer gives is one approach in which you modify the data "as it goes through" a filter stream to its destination.
Another approach is to send the output to a
ByteArrayOutputStream, extract the contents to a byte array, modify the bytes, and finally write them to your "real" output stream.Or you could extend
ByteArrayOutputStreamand override itsclose()method to do things when the stream is closed ... if that is what you mean. Or you could overridegetBytesto modify the bytes before returning them. Or override thewritemethod to modify the bytes as they are being written. There are many ways you could approach it, depending on precisely what your requirements are.您可以编写自己的 FilterOutputStream：
该类是所有过滤输出流的类的超类。这些流位于现有的输出流（底层输出流）之上，它用作基本数据接收器，但可能会沿途转换数据或提供附加功能。
You can write your own FilterOutputStream:
This class is the superclass of all classes that filter output streams. These streams sit on top of an already existing output stream (the underlying output stream) which it uses as its basic sink of data, but possibly transforming the data along the way or providing additional functionality.