Maybe another option would be to implement BufferedWriter with a StringBuilder rather than a char[]. This would remove the force to utf-16
On Sun, Jun 29, 2025 at 10:36 PM Brett Okken <brett.okken...@gmail.com> wrote: > Is StreamEncoder buffering content to only write to the underlying > OutputStream when some threshold is hit? While the layers of conversions > are unfortunate, it seems there could be negative performance implications > of having many extremely small writes (such as 1 character/byte) at a time > to the underlying OutputStream. > > Presumably this is a common pattern, as it is recommended: > > https://github.com/openjdk/jdk/blob/4dd1b3a6100f9e379c7cee3c699d63d0d01144a7/src/java.base/share/classes/java/io/OutputStreamWriter.java#L45 > > > On Sun, Jun 29, 2025 at 11:04 AM wenshao <shaojin.we...@alibaba-inc.com> > wrote: > >> BufferedWriter -> OutputStreamWriter -> StreamEncoder >> >> In this call chain, BufferedWriter has a char[] buffer, and StreamEncoder >> has a ByteBuffer. There are two layers of cache here, or the BufferedWriter >> layer can be removed. >> >> LATIN1 (byte[]) -> UTF16 (char[]) -> UTF8 (byte[]) >> >> And when charset is UTF8, if the content of write(String) is LATIN1, a >> conversion from LATIN1 to UTF16 and then to LATIN1 will occur here. >> >> We can improve BufferedWriter. When the parameter Writer instanceof >> OutputStreamWriter is passed in, remove the cache and call it directly. In >> addition, improve write(String) in StreamEncoder to avoid unnecessary >> encoding conversion. >> >> - >> Shaojin Wen >> >
