Tomcat服务器始终压缩为gzip（即使没有Accept-Encoding字段）(Tomcat server is always compressing as gzip (even when Accept-Encoding field is absent))

 我最近开始使用Apache Tomcat，我的一项任务是在动态Web内容上启用gzip压缩。 虽然我在网上找到了这个功能的一些实现，但最后我选择按照这里的说明（ http://viralpatel.net/blogs/enable-gzip-compression-in-tomcat/ ）并添加以下行我的server.xml文件的连接器部分。 
 
compression="on" 
noCompressionUserAgents="gozilla, traviata" 
compressionMinSize="2048" 
compressableMimeType="text/html,text/xml,application/json"
 
 编辑完文件并重新启动服务器后，我开始使用Postman测试我的一个servlet。 我发现大于2048的正确MIME类型的所有内容都被压缩 - 即使我没有发送Accept-Encoding：gzip标头。 我测试了几种方法，包括切换压缩几次，调整compressableMimeType值，以及摆弄compressionMinSize，但尽管我可以告诉这个实现不检查是否已包含Accept-Encoding标头。 
 
 虽然我可以相信这可能是一个不必要的功能，因为现代浏览器在2000年开始支持压缩，我想确保我覆盖了我的所有基础。 我假设我在这里遗漏了一些小事，因为我无法在网上找到这个问题的答案。 我已经包含了我的server.xml的副本，我正在运行Apache Tomcat 7.0.65，我会感谢任何和所有的帮助，以确定为什么我似乎无法选择不接收来自我新配置的服务器的压缩响应。 
 
<?xml version='1.0' encoding='utf-8'?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<Server port="8005" shutdown="SHUTDOWN">
<Listener className="org.apache.catalina.startup.VersionLoggerListener" />
<Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
<Listener className="org.apache.catalina.core.JasperListener" />
<Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
<Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

<GlobalNamingResources>
<Resource name="UserDatabase" auth="Container"
          type="org.apache.catalina.UserDatabase"
          description="User database that can be updated and saved"
          factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
          pathname="conf/tomcat-users.xml" />
</GlobalNamingResources>

<Service name="Catalina">

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
           redirectPort="8443"
    compression="on" 
    noCompressionUserAgents="gozilla, traviata" 
    compressionMinSize="2048" 
    compressableMimeType="text/html,text/xml" />

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

<Engine name="Catalina" defaultHost="localhost">

  <Realm className="org.apache.catalina.realm.LockOutRealm">
    <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
           resourceName="UserDatabase"/>
  </Realm>

  <Host name="localhost"  appBase="webapps"
        unpackWARs="true" autoDeploy="true">

    <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
           prefix="localhost_access_log." suffix=".txt"
           pattern="%h %l %u %t &quot;%r&quot; %s %b" />

      </Host>
    </Engine>
  </Service>
</Server>

I recently started working with Apache Tomcat, and one of my assignments was to enable gzip compression on our dynamic web content. While I found a number of implementations for this feature online, in the end I chose to follow the instructions here (http://viralpatel.net/blogs/enable-gzip-compression-in-tomcat/) and add the following lines to the connector section of my server.xml file.
 
compression="on" 
noCompressionUserAgents="gozilla, traviata" 
compressionMinSize="2048" 
compressableMimeType="text/html,text/xml,application/json"
 
Once I edited the file and restarted my server I started testing one of my servlets using Postman. I found that everything of the correct MIME types, larger than 2048, was getting compressed – even when I didn’t send the Accept-Encoding:gzip header. I tested this several ways, including toggling compression a few times, adjusting the compressableMimeType value, and fiddling with the compressionMinSize, but as near as I can tell this implementation is not checking to see if the Accept-Encoding header has been included. 
 
While I can believe this may be an unnecessary feature since modern browsers started supporting compression back in 2000, I wanted to ensure I was covering all of my bases. I am assuming I am missing something trivial here because I haven’t been able to find the answer to this question online. I have included a copy of my server.xml, I am running Apache Tomcat 7.0.65, and I would appreciate any and all help as far as determining why I can’t seem to opt out of receiving compressed responses from my newly configured server.
 
<?xml version='1.0' encoding='utf-8'?>
<!--
Licensed to the Apache Software Foundation (ASF) under one or more
contributor license agreements.  See the NOTICE file distributed with
this work for additional information regarding copyright ownership.
The ASF licenses this file to You under the Apache License, Version 2.0
(the "License"); you may not use this file except in compliance with
the License.  You may obtain a copy of the License at

  http://www.apache.org/licenses/LICENSE-2.0

Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.
-->
<Server port="8005" shutdown="SHUTDOWN">
<Listener className="org.apache.catalina.startup.VersionLoggerListener" />
<Listener className="org.apache.catalina.core.AprLifecycleListener" SSLEngine="on" />
<Listener className="org.apache.catalina.core.JasperListener" />
<Listener className="org.apache.catalina.core.JreMemoryLeakPreventionListener" />
<Listener className="org.apache.catalina.mbeans.GlobalResourcesLifecycleListener" />
<Listener className="org.apache.catalina.core.ThreadLocalLeakPreventionListener" />

<GlobalNamingResources>
<Resource name="UserDatabase" auth="Container"
          type="org.apache.catalina.UserDatabase"
          description="User database that can be updated and saved"
          factory="org.apache.catalina.users.MemoryUserDatabaseFactory"
          pathname="conf/tomcat-users.xml" />
</GlobalNamingResources>

<Service name="Catalina">

<Connector port="8080" protocol="HTTP/1.1"
           connectionTimeout="20000"
           redirectPort="8443"
    compression="on" 
    noCompressionUserAgents="gozilla, traviata" 
    compressionMinSize="2048" 
    compressableMimeType="text/html,text/xml" />

<Connector port="8009" protocol="AJP/1.3" redirectPort="8443" />

<Engine name="Catalina" defaultHost="localhost">

  <Realm className="org.apache.catalina.realm.LockOutRealm">
    <Realm className="org.apache.catalina.realm.UserDatabaseRealm"
           resourceName="UserDatabase"/>
  </Realm>

  <Host name="localhost"  appBase="webapps"
        unpackWARs="true" autoDeploy="true">

    <Valve className="org.apache.catalina.valves.AccessLogValve" directory="logs"
           prefix="localhost_access_log." suffix=".txt"
           pattern="%h %l %u %t &quot;%r&quot; %s %b" />

      </Host>
    </Engine>
  </Service>
</Server>

原文：https://stackoverflow.com/questions/35948793