参考自 https://blog.csdn.net/u010429286/article/details/54381705
现象
上传文件报错
org.springframework.web.multipart.MultipartException
Could not parse multipart servlet request; nested exception is java.lang.IllegalStateException:
org.apache.tomcat.util.http.fileupload.FileUploadBase$FileSizeLimitExceededException: The field image exceeds its maximum permitted size of 1048576 bytes.
分析
通过百度发现是spring-boot上传文件是有大小限制的，可以通过配置文件修改
解决
查看了官方文档，原来Spring Boot工程嵌入的tomcat限制了请求的文件大小，这一点在Spring Boot的官方文档中有说明，原文如下
65.5 Handling Multipart File Uploads
Spring Boot embraces the Servlet 3 javax.servlet.http.Part API to support uploading files. By default Spring Boot configures Spring MVC with a maximum file of 1Mb per file and a maximum of 10Mb of file data in a single request. You may override these values, as well as the location to which intermediate data is stored (e.g., to the /tmp directory) and the threshold past which data is flushed to disk by using the properties exposed in the MultipartProperties class. If you want to specify that files be unlimited, for example, set the multipart.maxFileSize property to -1.The multipart support is helpful when you want to receive multipart encoded file data as a @RequestParam-annotated parameter of type MultipartFile in a Spring MVC controller handler method.
文档说明表示，每个文件的配置最大为1Mb，单次请求的文件的总数不能大于10Mb。要更改这个默认值需要在配置文件（如application.properties）中加入两个配置
multipart.maxFileSize = 10Mb
multipart.maxRequestSize=100Mb
multipart.maxFileSize=10Mb是设置单个文件的大小, multipart.maxRequestSize=100Mb是设置单次请求的文件的总大小
如果是想要不限制文件上传的大小，那么就把两个值都设置为-1就行啦
*****************************后续更新******************************
Spring Boot1.4版本后配置更改为:
spring.http.multipart.maxFileSize = 10Mb spring.http.multipart.maxRequestSize=100Mb
Spring Boot2.0之后的版本配置修改为:
spring.servlet.multipart.max-file-size = 10Mb
spring.http.multipart.max-request-size=100Mb