spring.http.multipart.maxFileSize=10Mb 
spring.http.multipart.maxRequestSize=10Mb 

private long parseSize(String size) { 
   Assert.hasLength(size, "Size must not be empty"); 
   size = size.toUpperCase(); 
   return size.endsWith("KB")?Long.valueOf(size.substring(0, size.length() - 2)).longValue() * 1024L:(size.endsWith("MB")?Long.valueOf(size.substring(0, size.length() - 2)).longValue() * 1024L * 1024L:Long.valueOf(size).longValue()); 
 } 

/** 
   * 文件上传配置 
   * @return 
   */ 
  @Bean 
  public MultipartConfigElement multipartConfigElement() { 
    MultipartConfigFactory factory = new MultipartConfigFactory(); 
    //文件最大 
    factory.setMaxFileSize("10240KB"); //KB,MB 
    /// 设置总上传数据总大小 
    factory.setMaxRequestSize("102400KB"); 
    return factory.createMultipartConfig(); 
  } 

@Configuration 
@SpringBootApplication 
public class Application { 
 
  public static void main(String[] args) throws Exception { 
    SpringApplication.run(Application.class, args); 
  } 
 
 
  /** 
   * 文件上传配置 
   * @return 
   */ 
  @Bean 
  public MultipartConfigElement multipartConfigElement() { 
    MultipartConfigFactory factory = new MultipartConfigFactory(); 
    //文件最大 
    factory.setMaxFileSize("10240KB"); //KB,MB 
    /// 设置总上传数据总大小 
    factory.setMaxRequestSize("102400KB"); 
    return factory.createMultipartConfig(); 
  } 
 
}