further occurrences of HTTP header parsing errors will be logged at DEBUG level.

1.   获取参数Json的值为null  

String json=request.getParameter("Json");

　　

首先检查是否有下面的东东，

 信息: Error parsing HTTP request header
 Note: further occurrences of HTTP header parsing errors will be logged at DEBUG level.

　　

如果有：说明tomcat  的head缓冲区大小不够，在server.xml中增加maxHttpHeaderSize字段:

<Connector URIEncoding="UTF-8" port="8080" protocol="org.apache.coyote.http11.Http11NioProtocol"
	useBodyEncodingForURI="false"
	enableLookups="false"
               connectionTimeout="20000"
               redirectPort="8443" maxHttpHeaderSize="你想要的大小"/>

　　

不过使用Web提交就不会出现这种问题,即使手机端再三强调使用的是Post方式,仍怀疑是因为使用的Get导致Header数据过长.

2.  更上面解决方案一样  maxHttpHeaderSize

org.apache.coyote.http11.HeadersTooLargeException: An attempt was made to write more data to the response headers than there was room available in the buffer.
Increase maxHttpHeaderSize on the connector or write less data into the response headers.