org.apache.commons.fileupload.FileUploadBase$InvalidContentTypeException:
用ajax提交form表单上传文件，出现以下错误
org.apache.commons.fileupload.FileUploadBase$InvalidContentTypeException: the request doesn't contain a multipart/form-data or multipart/mixed stream, content type header is application/x-www-form-urlencoded; charset=UTF-8
at org.apache.commons.fileupload.FileUploadBase$FileItemIteratorImpl.<init>(FileUploadBase.java:947)
at org.apache.commons.fileupload.FileUploadBase.getItemIterator(FileUploadBase.java:310)
at org.apache.commons.fileupload.FileUploadBase.parseRequest(FileUploadBase.java:334)
at org.apache.commons.fileupload.servlet.ServletFileUpload.parseRequest(ServletFileUpload.java:115)
at com.qiye.EnterpriseServlet.update(EnterpriseServlet.java:252)
at com.qiye.EnterpriseServlet.doPost(EnterpriseServlet.java:91)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:641)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:722)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at com.filter.MyFilter.doFilter(MyFilter.java:90)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:225)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:169)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:472)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:168)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:98)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:927)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:407)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:999)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:565)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:309)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:745)
通过 传统的 form 表单提交的方式上传文件：
<form id= "uploadForm" action= "http://localhost:8080/cfJAX_RS/rest/file/upload" method= "post" enctype ="multipart/form-data"> <h1 >测试通过Rest接口上传文件 </h1> <p >指定文件名： <input type ="text" name="filename" /></p> <p >上传文件： <input type ="file" name="file" /></p> <p >关键字1： <input type ="text" name="keyword" /></p> <p >关键字2： <input type ="text" name="keyword" /></p> <p >关键字3： <input type ="text" name="keyword" /></p> <input type ="submit" value="上传"/> </form>
不过 传统的 form 表单提交会导致页面刷新， 但是在有些情况下，我们不希望页面被刷新，这种时候我们都是使用Ajax的方式进行请求的：
$.ajax({
url : "http://localhost:8080/STS/rest/user", type : "POST", data : $( '#postForm').serialize(), success : function(data) { $( '#serverResponse').html(data); }, error : function(data) { $( '#serverResponse').html(data.status + " : " + data.statusText + " : " + data.responseText); } });
如上，通过 $( '#postForm' ).serialize() 可以对form表单进行序列化，从而将form表单中的所有参数传递到服务端。
但是上述方式，只能传递一般的参数， 上传文件的文件流是无法被序列化并传递的。
不过如今主流浏览器都开始支持一个叫做FormData的对象，有了这个FormData，我们就可以轻松地使用Ajax方式进行文件 上传 了。
正确的方法是：
使用FormData，进行Ajax请求并上传文件
<form id= "uploadForm"> <p >指定文件名： <input type="text" name="filename" value= ""/></p > <p >上传文件： <input type="file" name="file"/></ p> <input type="button" value="上传" onclick="doUpload()" /> </form>
function doUpload() { var formData = new FormData($( "#uploadForm" )[0]); $.ajax({ url: 'http://localhost:8080/cfJAX_RS/rest/file/upload' , type: 'POST', data: formData, async: false, cache: false, contentType: false, processData: false, success: function (returndata) { alert(returndata); }, error: function (returndata) { alert(returndata); } }); }
一定要记得把form表单头里面除了id以为的数据去掉，不然会报错，为什么我也不知道
来自：http://www.tuicool.com/articles/IJrAna3