ServletOutputStreamImpl.java 文件源码

/**
 * {@inheritDoc}
 */
public void flush() throws IOException {
    //according to the servlet spec we ignore a flush from within an include
    if (servletRequestContext.getOriginalRequest().getDispatcherType() == DispatcherType.INCLUDE ||
            servletRequestContext.getOriginalResponse().isTreatAsCommitted()) {
        return;
    }
    if (servletRequestContext.getDeployment().getDeploymentInfo().isIgnoreFlush() &&
            servletRequestContext.getExchange().isRequestComplete() &&
            servletRequestContext.getOriginalResponse().getHeader(Headers.TRANSFER_ENCODING_STRING) == null) {
        //we mark the stream as flushed, but don't actually flush
        //because in most cases flush just kills performance
        //we only do this if the request is fully read, so that http tunneling scenarios still work
        servletRequestContext.getOriginalResponse().setIgnoredFlushPerformed(true);
        return;
    }
    flushInternal();
}