问题
Should the StreamingOutput's OutputStream be closed by the implementing class?
The java-doc does not give any recommendations. I guess it just delegates to the underlying ServletOutputStream which means it should not be closed, but my guess might be wrong :) Also the javadoc makes a reference to the MessageBodyWriter interface where it's explicitly said that the output stream must not be closed.
https://docs.oracle.com/javaee/7/api/javax/ws/rs/core/StreamingOutput.html
回答1:
Being unable to find a definitive answer I took a look at jersey's source being the reference implementation. In Jersey the StreamingOutput is processed by a MessageBodyWriter by simply calling streamingOutput.write(os) [1] where os is the OutputStream passed to the MessageBodyWriter. That's good because its javadoc is quite clear that this OutputStream must not be closed.
To summarize: The OutputStream passed to the StreamingOutput must not be closed.
[1] https://github.com/jersey/jersey/blob/master/core-common/src/main/java/org/glassfish/jersey/message/internal/StreamingOutputProvider.java
来源：https://stackoverflow.com/questions/39572872/closing-jax-rs-streamingoutputs-outputstream