Going to buffer response body of large or unknown size. Using getResponseBodyAsS

使用HttpClient，总是报出“Going to buffer response body of large or unknown size. Using getResponseBodyAsStream instead is recommended.”的WARN日志，定位到HttpClient的源码如下：

public byte [ ] getResponseBody( ) throws IOException {
if ( this .responseBody == null ) {
InputStream instream = getResponseBodyAsStream( ) ;
if ( instream != null ) {
long contentLength = getResponseContentLength( ) ;
if ( contentLength > Integer .MAX_VALUE ) { //guard below cast from overflow
throw new IOException ( "Content too large to be buffered: " + contentLength + " bytes" ) ;
}
int limit = getParams( ) .getIntParameter ( HttpMethodParams.BUFFER_WARN_TRIGGER_LIMIT , 1024 * 1024 ) ;
if ( ( contentLength == - 1 ) || ( contentLength > limit) ) {
LOG.warn ( "Going to buffer response body of large or unknown size. "
+ "Using getResponseBodyAsStream instead is recommended." ) ;
}
LOG.debug ( "Buffering response body" ) ;
ByteArrayOutputStream outstream = new ByteArrayOutputStream (
contentLength > 0 ? ( int ) contentLength : DEFAULT_INITIAL_BUFFER_SIZE) ;
byte [ ] buffer = new byte [ 4096 ] ;
int len;
while ( ( len = instream.read ( buffer) ) > 0 ) {
outstream.write ( buffer, 0 , len) ;
}
outstream.close ( ) ;
setResponseStream( null ) ;
this .responseBody = outstream.toByteArray ( ) ;
}
}
return this .responseBody ;
}

报WARN的条件是 ((contentLength == -1) || (contentLength > limit))，也就是说，或者是返回的HTTP头没有指定contentLength，或者是contentLength大于上限（默认是1M）。如果 能确定返回结果的大小对程序没有显著影响，这个WARN就可以忽略，可以在日志的配置中把HttpClient的日志级别调到ERROR，不让它报出来。

当然，这个警告也是有意义的，HttpClient建议使用InputStream getResponseBodyAsStream()代替byte[] getResponseBody()。对于返回结果很大或无法预知的情况，就需要使用InputStream getResponseBodyAsStream()，避免byte[] getResponseBody()可能带来的内存的耗尽问题。

使用String response = method.getResponseBodyAsString().trim(); 获得getMethod返回的内容，

每次都出现如下警告：

[WARN org.apache.commons.httpclient.HttpMethodBase] Going to buffer response body of

large or unknown size. Using getResponseBodyAsStream instead is recommended.

解决方法：

//String response = method.getResponseBodyAsString().trim();
InputStream resStream = method.getResponseBodyAsStream();
BufferedReader br = new
 BufferedReader(
new
 InputStreamReader(resStream));
StringBuffer resBuffer = new
 StringBuffer();
String resTemp = ""
;
while
((resTemp = br.readLine()) != 
null
){
resBuffer.append(resTemp);
}
String response = resBuffer.toString();

//String response = method.getResponseBodyAsString().trim(); InputStream resStream = method.getResponseBodyAsStream(); BufferedReader br = new BufferedReader(new InputStreamReader(resStream)); StringBuffer resBuffer = new StringBuffer(); String resTemp = ""; while((resTemp = br.readLine()) != null){ resBuffer.append(resTemp); } String response = resBuffer.toString();

response
.
addHeader
(
"Content-Type"
,
"text/html; charset=utf-8"
);


response
.
addHeader
(
"Content-Length"
,
 
String
.
valueOf
(
output
.
getBytes
(
"utf8"
).
length
));