事故现场截图
企业微信截图_17047861244282.png
事故原因
企业微信截图_17047864542464.png
源码分析
1、StandardMultipartHttpServletRequest
private void parseRequest(HttpServletRequest request) {
try {
//
Collection<Part> parts = request.getParts();
this.multipartParameterNames = new LinkedHashSet<>(parts.size());
MultiValueMap<String, MultipartFile> files = new LinkedMultiValueMap<>(parts.size());
for (Part part : parts) {
String headerValue = part.getHeader(HttpHeaders.CONTENT_DISPOSITION);
ContentDisposition disposition = ContentDisposition.parse(headerValue);
String filename = disposition.getFilename();
if (filename != null) {
if (filename.startsWith("=?") && filename.endsWith("?=")) {
filename = MimeDelegate.decode(filename);
}
files.add(part.getName(), new StandardMultipartFile(part, filename));
}
else {
this.multipartParameterNames.add(part.getName());
}
}
setMultipartFiles(files);
}
catch (Throwable ex) {
handleParseFailure(ex);
}
}
事故入口
@Override
public Collection<Part> getParts() throws IOException,
ServletException {
return this._getHttpServletRequest().getParts();
}
// 进入到Request实现类
@Override
public Collection<Part> getParts() throws IOException, IllegalStateException,
ServletException {
//核心处理方法
parseParts(true);
if (partsParseException != null) {
if (partsParseException instanceof IOException) {
throw (IOException) partsParseException;
} else if (partsParseException instanceof IllegalStateException) {
throw (IllegalStateException) partsParseException;
} else if (partsParseException instanceof ServletException) {
throw (ServletException) partsParseException;
}
}
return parts;
}
private void parseParts(boolean explicit) {
// Return immediately if the parts have already been parsed
if (parts != null || partsParseException != null) {
return;
}
Context context = getContext();
// 这个是什么，从哪来 到哪去？
MultipartConfigElement mce = getWrapper().getMultipartConfigElement();
if (mce == null) {
// 如果没有配置默认给了2M
if(context.getAllowCasualMultipartParsing()) {
mce = new MultipartConfigElement(null,
connector.getMaxPostSize(),
connector.getMaxPostSize(),
connector.getMaxPostSize());
} else {
if (explicit) {
partsParseException = new IllegalStateException(
sm.getString("coyoteRequest.noMultipartConfig"));
return;
} else {
parts = Collections.emptyList();
return;
}
}
}
Parameters parameters = coyoteRequest.getParameters();
parameters.setLimit(getConnector().getMaxParameterCount());
boolean success = false;
try {
File location;
String locationStr = mce.getLocation();
if (locationStr == null || locationStr.length() == 0) {
location = ((File) context.getServletContext().getAttribute(
ServletContext.TEMPDIR));
} else {
// If relative, it is relative to TEMPDIR
location = new File(locationStr);
if (!location.isAbsolute()) {
location = new File(
(File) context.getServletContext().getAttribute(
ServletContext.TEMPDIR),
locationStr).getAbsoluteFile();
}
}
if (!location.isDirectory()) {
parameters.setParseFailedReason(FailReason.MULTIPART_CONFIG_INVALID);
partsParseException = new IOException(
sm.getString("coyoteRequest.uploadLocationInvalid",
location));
return;
}
// Create a new file upload handler
DiskFileItemFactory factory = new DiskFileItemFactory();
try {
factory.setRepository(location.getCanonicalFile());
} catch (IOException ioe) {
parameters.setParseFailedReason(FailReason.IO_ERROR);
partsParseException = ioe;
return;
}
factory.setSizeThreshold(mce.getFileSizeThreshold());
ServletFileUpload upload = new ServletFileUpload();
upload.setFileItemFactory(factory);
// 配置扔进来
upload.setFileSizeMax(mce.getMaxFileSize());
upload.setSizeMax(mce.getMaxRequestSize());
parts = new ArrayList<>();
try {
List<FileItem> items =
//处理方法
upload.parseRequest(new ServletRequestContext(this));
int maxPostSize = getConnector().getMaxPostSize();
int postSize = 0;
Charset charset = getCharset();
for (FileItem item : items) {
ApplicationPart part = new ApplicationPart(item, location);
parts.add(part);
if (part.getSubmittedFileName() == null) {
String name = part.getName();
String value = null;
try {
value = part.getString(charset.name());
} catch (UnsupportedEncodingException uee) {
// Not possible
}
if (maxPostSize >= 0) {
// Have to calculate equivalent size. Not completely
// accurate but close enough.
postSize += name.getBytes(charset).length;
if (value != null) {
// Equals sign
postSize++;
// Value length
postSize += part.getSize();
}
// Value separator
postSize++;
if (postSize > maxPostSize) {
parameters.setParseFailedReason(FailReason.POST_TOO_LARGE);
throw new IllegalStateException(sm.getString(
"coyoteRequest.maxPostSizeExceeded"));
}
}
parameters.addParameter(name, value);
}
}
success = true;
} catch (InvalidContentTypeException e) {
parameters.setParseFailedReason(FailReason.INVALID_CONTENT_TYPE);
partsParseException = new ServletException(e);
} catch (FileUploadBase.SizeException e) {
parameters.setParseFailedReason(FailReason.POST_TOO_LARGE);
checkSwallowInput();
partsParseException = new IllegalStateException(e);
} catch (FileUploadException e) {
parameters.setParseFailedReason(FailReason.IO_ERROR);
partsParseException = new IOException(e);
} catch (IllegalStateException e) {
// addParameters() will set parseFailedReason
checkSwallowInput();
partsParseException = e;
}
} finally {
// This might look odd but is correct. setParseFailedReason() only
// sets the failure reason if none is currently set. This code could
// be more efficient but it is written this way to be robust with
// respect to changes in the remainder of the method.
if (partsParseException != null || !success) {
parameters.setParseFailedReason(FailReason.UNKNOWN);
}
}
}
image.png
FileUploaBase 处理类
public List<FileItem> parseRequest(RequestContext ctx)
throws FileUploadException {
List<FileItem> items = new ArrayList<>();
boolean successful = false;
try {
//处理请求对象上下文
FileItemIterator iter = getItemIterator(ctx);
FileItemFactory fac = getFileItemFactory();
if (fac == null) {
throw new NullPointerException("No FileItemFactory has been set.");
}
while (iter.hasNext()) {
final FileItemStream item = iter.next();
// Don't use getName() here to prevent an InvalidFileNameException.
final String fileName = ((FileItemIteratorImpl.FileItemStreamImpl) item).name;
FileItem fileItem = fac.createItem(item.getFieldName(), item.getContentType(),
item.isFormField(), fileName);
items.add(fileItem);
try {
Streams.copy(item.openStream(), fileItem.getOutputStream(), true);
} catch (FileUploadIOException e) {
throw (FileUploadException) e.getCause();
} catch (IOException e) {
throw new IOFileUploadException(String.format("Processing of %s request failed. %s",
MULTIPART_FORM_DATA, e.getMessage()), e);
}
final FileItemHeaders fih = item.getHeaders();
fileItem.setHeaders(fih);
}
successful = true;
return items;
} catch (FileUploadIOException e) {
throw (FileUploadException) e.getCause();
} catch (IOException e) {
throw new FileUploadException(e.getMessage(), e);
} finally {
if (!successful) {
for (FileItem fileItem : items) {
try {
fileItem.delete();
} catch (Exception ignored) {
// ignored TODO perhaps add to tracker delete failure list somehow?
}
}
}
}
}
public FileItemIterator getItemIterator(RequestContext ctx)
throws FileUploadException, IOException {
try {
return new FileItemIteratorImpl(ctx);
} catch (FileUploadIOException e) {
// unwrap encapsulated SizeException
throw (FileUploadException) e.getCause();
}
}
FileItemIteratorImpl(RequestContext ctx)
throws FileUploadException, IOException {
if (ctx == null) {
throw new NullPointerException("ctx parameter");
}
String contentType = ctx.getContentType();
if ((null == contentType)
|| (!contentType.toLowerCase(Locale.ENGLISH).startsWith(MULTIPART))) {
throw new InvalidContentTypeException(String.format(
"the request doesn't contain a %s or %s stream, content type header is %s",
MULTIPART_FORM_DATA, MULTIPART_MIXED, contentType));
}
// 获取整体报文长度
final long requestSize = ((UploadContext) ctx).contentLength();
// 下方使用配置报文长度和请求报文长度校验
InputStream input; // N.B. this is eventually closed in MultipartStream processing
if (sizeMax >= 0) {
if (requestSize != -1 && requestSize > sizeMax) {
throw new SizeLimitExceededException(String.format(
"the request was rejected because its size (%s) exceeds the configured maximum (%s)",
Long.valueOf(requestSize), Long.valueOf(sizeMax)),
requestSize, sizeMax);
}
// N.B. this is eventually closed in MultipartStream processing
input = new LimitedInputStream(ctx.getInputStream(), sizeMax) {
@Override
protected void raiseError(long pSizeMax, long pCount)
throws IOException {
FileUploadException ex = new SizeLimitExceededException(
String.format("the request was rejected because its size (%s) exceeds the configured maximum (%s)",
Long.valueOf(pCount), Long.valueOf(pSizeMax)),
pCount, pSizeMax);
throw new FileUploadIOException(ex);
}
};
} else {
input = ctx.getInputStream();
}
String charEncoding = headerEncoding;
if (charEncoding == null) {
charEncoding = ctx.getCharacterEncoding();
}
boundary = getBoundary(contentType);
if (boundary == null) {
IOUtils.closeQuietly(input); // avoid possible resource leak
throw new FileUploadException("the request was rejected because no multipart boundary was found");
}
notifier = new MultipartStream.ProgressNotifier(listener, requestSize);
try {
multi = new MultipartStream(input, boundary, notifier);
} catch (IllegalArgumentException iae) {
IOUtils.closeQuietly(input); // avoid possible resource leak
throw new InvalidContentTypeException(
String.format("The boundary specified in the %s header is too long", CONTENT_TYPE), iae);
}
multi.setHeaderEncoding(charEncoding);
skipPreamble = true;
//开始校验文件
findNextItem();
}
image.png
private boolean findNextItem() throws IOException {
if (eof) {
return false;
}
if (currentItem != null) {
currentItem.close();
currentItem = null;
}
for (;;) {
boolean nextPart;
if (skipPreamble) {
nextPart = multi.skipPreamble();
} else {
nextPart = multi.readBoundary();
}
if (!nextPart) {
if (currentFieldName == null) {
// Outer multipart terminated -> No more data
eof = true;
return false;
}
// Inner multipart terminated -> Return to parsing the outer
multi.setBoundary(boundary);
currentFieldName = null;
continue;
}
FileItemHeaders headers = getParsedHeaders(multi.readHeaders());
if (currentFieldName == null) {
// We're parsing the outer multipart
String fieldName = getFieldName(headers);
if (fieldName != null) {
String subContentType = headers.getHeader(CONTENT_TYPE);
if (subContentType != null
&& subContentType.toLowerCase(Locale.ENGLISH)
.startsWith(MULTIPART_MIXED)) {
currentFieldName = fieldName;
// Multiple files associated with this field name
byte[] subBoundary = getBoundary(subContentType);
multi.setBoundary(subBoundary);
skipPreamble = true;
continue;
}
String fileName = getFileName(headers);
// 生成文件流
currentItem = new FileItemStreamImpl(fileName,
fieldName, headers.getHeader(CONTENT_TYPE),
fileName == null, getContentLength(headers));
currentItem.setHeaders(headers);
notifier.noteItem();
itemValid = true;
return true;
}
} else {
String fileName = getFileName(headers);
if (fileName != null) {
// 生成文件流
currentItem = new FileItemStreamImpl(fileName,
currentFieldName,
headers.getHeader(CONTENT_TYPE),
false, getContentLength(headers));
currentItem.setHeaders(headers);
notifier.noteItem();
itemValid = true;
return true;
}
}
multi.discardBodyData();
}
}
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;
}
image.png
问题来了 fileSizeMax 和 sizeMax 在哪里配置呢
@Configuration
@ConditionalOnClass({ Servlet.class, StandardServletMultipartResolver.class,
MultipartConfigElement.class })
@ConditionalOnProperty(prefix = "spring.servlet.multipart", name = "enabled", matchIfMissing = true)
@ConditionalOnWebApplication(type = Type.SERVLET)
@EnableConfigurationProperties(MultipartProperties.class)
public class MultipartAutoConfiguration {
private final MultipartProperties multipartProperties;
public MultipartAutoConfiguration(MultipartProperties multipartProperties) {
this.multipartProperties = multipartProperties;
}
@Bean
@ConditionalOnMissingBean
public MultipartConfigElement multipartConfigElement() {
//这里创建一个配置类
return this.multipartProperties.createMultipartConfig();
}
@Bean(name = DispatcherServlet.MULTIPART_RESOLVER_BEAN_NAME)
@ConditionalOnMissingBean(MultipartResolver.class)
public StandardServletMultipartResolver multipartResolver() {
StandardServletMultipartResolver multipartResolver = new StandardServletMultipartResolver();
multipartResolver.setResolveLazily(this.multipartProperties.isResolveLazily());
return multipartResolver;
}
}
image.png
容器启动时loadServlet（） MultipartConfigElement 装配到wapper
public synchronized Servlet loadServlet() throws ServletException {
// Nothing to do if we already have an instance or an instance pool
if (!singleThreadModel && (instance != null))
return instance;
PrintStream out = System.out;
if (swallowOutput) {
SystemLogHandler.startCapture();
}
Servlet servlet;
try {
long t1=System.currentTimeMillis();
// Complain if no servlet class has been specified
if (servletClass == null) {
unavailable(null);
throw new ServletException
(sm.getString("standardWrapper.notClass", getName()));
}
InstanceManager instanceManager = ((StandardContext)getParent()).getInstanceManager();
try {
servlet = (Servlet) instanceManager.newInstance(servletClass);
} catch (ClassCastException e) {
unavailable(null);
// Restore the context ClassLoader
throw new ServletException
(sm.getString("standardWrapper.notServlet", servletClass), e);
} catch (Throwable e) {
e = ExceptionUtils.unwrapInvocationTargetException(e);
ExceptionUtils.handleThrowable(e);
unavailable(null);
// Added extra log statement for Bugzilla 36630:
// http://bz.apache.org/bugzilla/show_bug.cgi?id=36630
if(log.isDebugEnabled()) {
log.debug(sm.getString("standardWrapper.instantiate", servletClass), e);
}
// Restore the context ClassLoader
throw new ServletException
(sm.getString("standardWrapper.instantiate", servletClass), e);
}
if (multipartConfigElement == null) {
MultipartConfig annotation =
servlet.getClass().getAnnotation(MultipartConfig.class);
if (annotation != null) {
multipartConfigElement =
new MultipartConfigElement(annotation);
}
}
// Special handling for ContainerServlet instances
// Note: The InstanceManager checks if the application is permitted
// to load ContainerServlets
if (servlet instanceof ContainerServlet) {
((ContainerServlet) servlet).setWrapper(this);
}
classLoadTime=(int) (System.currentTimeMillis() -t1);
if (servlet instanceof SingleThreadModel) {
if (instancePool == null) {
instancePool = new Stack<>();
}
singleThreadModel = true;
}
initServlet(servlet);
fireContainerEvent("load", this);
loadTime=System.currentTimeMillis() -t1;
} finally {
if (swallowOutput) {
String log = SystemLogHandler.stopCapture();
if (log != null && log.length() > 0) {
if (getServletContext() != null) {
getServletContext().log(log);
} else {
out.println(log);
}
}
}
}
return servlet;
}
image.png
