原本用的2.0.x的版本上传文件是没有问题的，后来升级SpringBoot版本为2.3.3就无法上传文件了，我看到MultipartFile是为空的。
不使用Multipart自动配置，再排除原有的Multipart配置@EnableAutoConfiguration(exclude = {MultipartAutoConfiguration.class})，然后显示声明CommonsMultipartResolver为mutipartResolver。
排除MultipartAutoConfiguration
java
@SpringBootApplication(exclude = {MultipartAutoConfiguration.class})
添加依赖
xml <dependency> <groupId>commons-io</groupId> <artifactId>commons-io</artifactId> <version>2.6</version> </dependency> <dependency> <groupId>commons-fileupload</groupId> <artifactId>commons-fileupload</artifactId> <version>1.4</version> </dependency>
显示声明CommonsMultipartResolver为mutipartResolver：
java
@Configuration
public class UploadResolverConfig {
/**
* 显示声明CommonsMultipartResolver为mutipartResolver
*
* @return
*/
@Bean(name = "multipartResolver")
public MultipartResolver multipartResolver() {
CommonsMultipartResolver resolver = new CommonsMultipartResolver();
resolver.setDefaultEncoding("UTF-8");
// resolveLazily属性启用是为了推迟文件解析，以在在UploadAction中捕获文件大小异常
resolver.setResolveLazily(true);
// 设置了文件放入临时文件夹的大小限制
resolver.setMaxInMemorySize(40960);
// 设置单个上传数据总大小25M
resolver.setMaxUploadSizePerFile(25 * 1024 * 1024);
// 设置总上传数据总大小50M
resolver.setMaxUploadSize(5 * 1024 * 1024);
return resolver;
}
}
java
/**
* {@link EnableAutoConfiguration Auto-configuration} for multi-part uploads. Adds a
* {@link StandardServletMultipartResolver} if none is present, and adds a
* {@link javax.servlet.MultipartConfigElement multipartConfigElement} if none is
* otherwise defined. The {@link ServletWebServerApplicationContext} will associate the
* {@link MultipartConfigElement} bean to any {@link Servlet} beans.
* <p>
* The {@link javax.servlet.MultipartConfigElement} is a Servlet API that's used to
* configure how the server handles file uploads.
*
* @author Greg Turnquist
* @author Josh Long
* @author Toshiaki Maki
* @since 2.0.0
*/
@Configuration(proxyBeanMethods = false)
@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({ MultipartConfigElement.class, CommonsMultipartResolver.class })
public MultipartConfigElement multipartConfigElement() {
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;
}
}
java
/**
* Servlet-based {@link MultipartResolver} implementation for
* <a href="https://commons.apache.org/proper/commons-fileupload">Apache Commons FileUpload</a>
* 1.2 or above.
*
* <p>Provides "maxUploadSize", "maxInMemorySize" and "defaultEncoding" settings as
* bean properties (inherited from {@link CommonsFileUploadSupport}). See corresponding
* ServletFileUpload / DiskFileItemFactory properties ("sizeMax", "sizeThreshold",
* "headerEncoding") for details in terms of defaults and accepted values.
*
* <p>Saves temporary files to the servlet container's temporary directory.
* Needs to be initialized <i>either</i> by an application context <i>or</i>
* via the constructor that takes a ServletContext (for standalone usage).
*
* @author Trevor D. Cook
* @author Juergen Hoeller
* @since 29.09.2003
* @see #CommonsMultipartResolver(ServletContext)
* @see #setResolveLazily
* @see org.apache.commons.fileupload.servlet.ServletFileUpload
* @see org.apache.commons.fileupload.disk.DiskFileItemFactory
*/
public class CommonsMultipartResolver extends CommonsFileUploadSupport
implements MultipartResolver, ServletContextAware {
private boolean resolveLazily = false;
/**
* Constructor for use as bean. Determines the servlet container's
* temporary directory via the ServletContext passed in as through the
* ServletContextAware interface (typically by a WebApplicationContext).
* @see #setServletContext
* @see org.springframework.web.context.ServletContextAware
* @see org.springframework.web.context.WebApplicationContext
*/
public CommonsMultipartResolver() {
super();
}
/**
* Constructor for standalone usage. Determines the servlet container's
* temporary directory via the given ServletContext.
* @param servletContext the ServletContext to use
*/
public CommonsMultipartResolver(ServletContext servletContext) {
this();
setServletContext(servletContext);
}
/**
* Set whether to resolve the multipart request lazily at the time of
* file or parameter access.
* <p>Default is "false", resolving the multipart elements immediately, throwing
* corresponding exceptions at the time of the {@link #resolveMultipart} call.
* Switch this to "true" for lazy multipart parsing, throwing parse exceptions
* once the application attempts to obtain multipart files or parameters.
*/
public void setResolveLazily(boolean resolveLazily) {
this.resolveLazily = resolveLazily;
}
/**
* Initialize the underlying {@code org.apache.commons.fileupload.servlet.ServletFileUpload}
* instance. Can be overridden to use a custom subclass, e.g. for testing purposes.
* @param fileItemFactory the Commons FileItemFactory to use
* @return the new ServletFileUpload instance
*/
@Override
protected FileUpload newFileUpload(FileItemFactory fileItemFactory) {
return new ServletFileUpload(fileItemFactory);
}
@Override
public void setServletContext(ServletContext servletContext) {
if (!isUploadTempDirSpecified()) {
getFileItemFactory().setRepository(WebUtils.getTempDir(servletContext));
}
}
@Override
public boolean isMultipart(HttpServletRequest request) {
return ServletFileUpload.isMultipartContent(request);
}
@Override
public MultipartHttpServletRequest resolveMultipart(final HttpServletRequest request) throws MultipartException {
Assert.notNull(request, "Request must not be null");
if (this.resolveLazily) {
return new DefaultMultipartHttpServletRequest(request) {
@Override
protected void initializeMultipart() {
MultipartParsingResult parsingResult = parseRequest(request);
setMultipartFiles(parsingResult.getMultipartFiles());
setMultipartParameters(parsingResult.getMultipartParameters());
setMultipartParameterContentTypes(parsingResult.getMultipartParameterContentTypes());
}
};
}
else {
MultipartParsingResult parsingResult = parseRequest(request);
return new DefaultMultipartHttpServletRequest(request, parsingResult.getMultipartFiles(),
parsingResult.getMultipartParameters(), parsingResult.getMultipartParameterContentTypes());
}
}
/**
* Parse the given servlet request, resolving its multipart elements.
* @param request the request to parse
* @return the parsing result
* @throws MultipartException if multipart resolution failed.
*/
protected MultipartParsingResult parseRequest(HttpServletRequest request) throws MultipartException {
String encoding = determineEncoding(request);
FileUpload fileUpload = prepareFileUpload(encoding);
try {
List<FileItem> fileItems = ((ServletFileUpload) fileUpload).parseRequest(request);
return parseFileItems(fileItems, encoding);
}
catch (FileUploadBase.SizeLimitExceededException ex) {
throw new MaxUploadSizeExceededException(fileUpload.getSizeMax(), ex);
}
catch (FileUploadBase.FileSizeLimitExceededException ex) {
throw new MaxUploadSizeExceededException(fileUpload.getFileSizeMax(), ex);
}
catch (FileUploadException ex) {
throw new MultipartException("Failed to parse multipart servlet request", ex);
}
}
/**
* Determine the encoding for the given request.
* Can be overridden in subclasses.
* <p>The default implementation checks the request encoding,
* falling back to the default encoding specified for this resolver.
* @param request current HTTP request
* @return the encoding for the request (never {@code null})
* @see javax.servlet.ServletRequest#getCharacterEncoding
* @see #setDefaultEncoding
*/
protected String determineEncoding(HttpServletRequest request) {
String encoding = request.getCharacterEncoding();
if (encoding == null) {
encoding = getDefaultEncoding();
}
return encoding;
}
@Override
public void cleanupMultipart(MultipartHttpServletRequest request) {
if (!(request instanceof AbstractMultipartHttpServletRequest) ||
((AbstractMultipartHttpServletRequest) request).isResolved()) {
try {
cleanupFileItems(request.getMultiFileMap());
}
catch (Throwable ex) {
logger.warn("Failed to perform multipart cleanup for servlet request", ex);
}
}
}
}
控制器使用
plaintext
@PostMapping("/upload")
public void bigStopFile(@RequestParam Map<String, MultipartFile> map,HttpServletRequest request, HttpServletResponse response) throws IOException {
......
}
注意 MultipartResolver 与 MultipartConfigElement 冲突，如果同时配置也会造成MultipartFile为空的情况，MultipartConfigElement配置方式如下：
plaintext
@Bean
public MultipartConfigElement multipartConfigElement() {
MultipartConfigFactory factory = new MultipartConfigFactory();
//factory.setLocation("/app/sinova/tmp");
//文件最大
factory.setMaxFileSize(DataSize.of(50, DataUnit.MEGABYTES));
/// 设置总上传数据总大小
factory.setMaxRequestSize(DataSize.of(200, DataUnit.MEGABYTES));
return factory.createMultipartConfig();
}