根据异常内提示的类，可以定位到：
FileUploadBase（class FileItemStreamImpl 的构造函数）
/**
* Creates a new instance.
*
* @param pName The items file name, or null.
* @param pFieldName The items field name.
* @param pContentType The items content type, or null.
* @param pFormField Whether the item is a form field.
* @param pContentLength The items content length, if known, or -1
* @throws IOException Creating the file item failed.
*/
FileItemStreamImpl(String pName, String pFieldName,
String pContentType, boolean pFormField,
long pContentLength) throws IOException {
name = pName;
fieldName = pFieldName;
contentType = pContentType;
formField = pFormField;
final ItemInputStream itemStream = multi.newInputStream();
InputStream istream = itemStream;
if (fileSizeMax != -1) {
if (pContentLength != -1
&& pContentLength > fileSizeMax) {
FileSizeLimitExceededException e =
new FileSizeLimitExceededException(
String.format("The field %s exceeds its maximum permitted size of %s bytes.",
fieldName, Long.valueOf(fileSizeMax)),
pContentLength, fileSizeMax);
e.setFileName(pName);
e.setFieldName(pFieldName);
throw new FileUploadIOException(e);
}
istream = new LimitedInputStream(istream, fileSizeMax) {
@Override
protected void raiseError(long pSizeMax, long pCount)
throws IOException {
itemStream.close(true);
FileSizeLimitExceededException e =
new FileSizeLimitExceededException(
String.format("The field %s exceeds its maximum permitted size of %s bytes.",
fieldName, Long.valueOf(pSizeMax)),
pCount, pSizeMax);
e.setFieldName(fieldName);
e.setFileName(name);
throw new FileUploadIOException(e);
}
};
}
stream = istream;
}
发现fileSizeMax该值控制上传上限，在207行看到
/**
* Sets the maximum allowed size of a single uploaded file,
* as opposed to {@link #getSizeMax()}.
*
* @see #getFileSizeMax()
* @param fileSizeMax Maximum size of a single uploaded file.
*/
public void setFileSizeMax(long fileSizeMax) {
this.fileSizeMax = fileSizeMax;
}
追踪后发现在Request类的parseParts方法（2863行）upload.setFileSizeMax(mce.getMaxFileSize());
mce对象是在2800行MultipartConfigElement mce = getWrapper().getMultipartConfigElement();初始化的。
通过getMultipartConfigElement()可在StandardWrapper内的1072行处发现如下代码
if (multipartConfigElement == null) {
MultipartConfig annotation =
servlet.getClass().getAnnotation(MultipartConfig.class);
if (annotation != null) {
multipartConfigElement =
new MultipartConfigElement(annotation);
}
}
最终发现 通过MultipartConfig注解可配置。
配置完不好使！！！
后发现可通过配置文件：
spring:
http:
multipart:
maxFileSize: 10Mb
maxRequestSize: 100Mb
