自从用nginx-1.2.3为solr4.6做负载均衡之后，只要是删除操作，就报如下堆栈：
org.apache.solr.client.solrj.impl.HttpSolrServer$RemoteSolrException: Expected content type application/octet-stream but got text/html. <html>
<head><title>411 Length Required</title></head>
<body bgcolor="white">
<center><h1>411 Length Required</h1></center>
<hr><center>nginx/1.2.3</center>
</body>
</html>
at org.apache.solr.client.solrj.impl.HttpSolrServer.request(HttpSolrServer.java:455)
at org.apache.solr.client.solrj.impl.HttpSolrServer.request(HttpSolrServer.java:197)
at org.apache.solr.client.solrj.impl.ConcurrentUpdateSolrServer.request(ConcurrentUpdateSolrServer.java:299)
at org.apache.solr.client.solrj.request.AbstractUpdateRequest.process(AbstractUpdateRequest.java:117)
at org.apache.solr.client.solrj.SolrServer.deleteByQuery(SolrServer.java:285)
at org.apache.solr.client.solrj.SolrServer.deleteByQuery(SolrServer.java:271)
at com.jd.soa.solr.write.impl.SolrWriteDaoImpl.deleteByQuery(SolrWriteDaoImpl.java:156)
at com.jd.soa.solr.write.impl.test.SolrWriteDaoImplTest.deleteByQueryTest(SolrWriteDaoImplTest.java:89)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:39)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:25)
at java.lang.reflect.Method.invoke(Method.java:597)
at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
at org.springframework.test.context.junit4.statements.RunBeforeTestMethodCallbacks.evaluate(RunBeforeTestMethodCallbacks.java:74)
at org.springframework.test.context.junit4.statements.RunAfterTestMethodCallbacks.evaluate(RunAfterTestMethodCallbacks.java:83)
at org.springframework.test.context.junit4.statements.SpringRepeat.evaluate(SpringRepeat.java:72)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.runChild(SpringJUnit4ClassRunner.java:231)
at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
at org.springframework.test.context.junit4.statements.RunBeforeTestClassCallbacks.evaluate(RunBeforeTestClassCallbacks.java:61)
at org.springframework.test.context.junit4.statements.RunAfterTestClassCallbacks.evaluate(RunAfterTestClassCallbacks.java:71)
at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
at org.springframework.test.context.junit4.SpringJUnit4ClassRunner.run(SpringJUnit4ClassRunner.java:174)
at org.eclipse.jdt.internal.junit4.runner.JUnit4TestReference.run(JUnit4TestReference.java:49)
at org.eclipse.jdt.internal.junit.runner.TestExecution.run(TestExecution.java:38)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:467)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.runTests(RemoteTestRunner.java:683)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.run(RemoteTestRunner.java:390)
at org.eclipse.jdt.internal.junit.runner.RemoteTestRunner.main(RemoteTestRunner.java:197)
不仅删除操作不成功，写操作虽然单元测试通过，但是上solr管理界面上查，并没有真正的写进去。
问题显然出在Nginx上，因为没有打通Nginx之前，所有CRUD单元测试都是正常的。返回结果也提示是Nginx-1.2.3把这个请求拦截了。
根据提示，我修改了nginx.conf的配置文件：
default_type application/octet-stream; ——>default_type text/html;
重启nginx， ./nginx -s reload。删除操作报同样的错误。
最终怀疑nginx的版本的问题，是不是我的solr太新了，4.6是当前solr的最新版本，会不会跟比较老的nginx-1.2.3不兼容？
于是上nginx官网download最新的nginx-1.5.9的代码包。放到服务器上，编译安装好之后。停掉老的1.2.3，重新配置1.5.9。
启动nginx-1.5.9,重新执行删除和写的单元测试，没有报异常。去solr4.6的管理界面查看数据，没有问题。
分享下我的解决办法，至于真正的原因，我也不是很清楚，慢慢的熟悉solr4.6吧。希望有经验的大神回复下，指出异常的根本原因。
Solr4.6 Expected content type application/octet-stream but got text/html 解决办法