• 由spring官方文件可知，spring-boot在MultipartProperties配置檔案中對最大上傳大小做了限制需要在啟動時增加一個配置類

• 在啟動類裡增加以下類即可解決問題

  /**
   * 解除上傳檔案的限制
   */
  @Configuration
  @ConditionalOnClass({Servlet.class, StandardServletMultipartResolver.class,
          MultipartConfigElement.class})
  @ConditionalOnProperty(prefix = "spring.http.multipart"
   
  , name = "enabled", matchIfMissing = true)
  @EnableConfigurationProperties(MultipartProperties.class)
  public class MultipartAutoConfiguration {
  
      private final MultipartProperties multipartProperties;
  
      public MultipartAutoConfiguration(MultipartProperties multipartProperties) {
          this.multipartProperties = multipartProperties;
          multipartProperties.setMaxFileSize("-1"
   
  );
      }
  
      @Bean
      @ConditionalOnMissingBean
      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;
      }
  
  }

以上參考springboot官方文件