How to convert Writer to String
Several answers suggest using StringWriter.It's important to realize that StringWriter uses StringBuffer internally, meaning that it's thread-safe and has a significant synchronization overhead.
If you need thread-safety for the writer, then
StringWriteris the way to go.If you don't need a thread safe
Writer(i.e. the writer is only used as a local variable in a single method) and you care for performance — consider usingStringBuilderWriterfrom the commons-io library.
StringBuilderWriter is almost the same as StringWriter, but uses StringBuilder instead of StringBuffer.
Sample usage:
Writer writer = new StringBuilderWriter();String data = writer.toString();Note — Log4j has its own StringBuilderWriter implementation which is almost identical to the commons-io version.