Java: 关于nested exception的理解

Question

像下面这个异常提示：

org.springframework.web.multipart.MultipartException: Could not parse multipart servlet request; nested exception is java.lang.IllegalStateException: org.apache.tomcat.util.http.fileupload.FileUploadBase$SizeLimitExceededException: the request was rejected because its size (45372783) exceeds the configured maximum (1048576)

MultipartException IllegalStateException SizeLimitExceededException
之间是什么关系？

Answer 1

MultipartException为springmvc封装的异常，抛出这个异常的原因在于产生了IllegalStateException，而产生IllegalStateException的原因是抛出了SizeLimitExceededException，这个异常产生的原因是你的请求上传内容大小超过了你配置的参数，如果服务器是tomcat的话，可以在server.xml中配置 maxPostSize这个参数,配置为0代表没有大小限制

<Connector executor="tomcatThreadPool"  
           port="8080" protocol="HTTP/1.1"  
           connectionTimeout="20000"  
           redirectPort="8443" maxPostSize="0" />