在項(xiàng)目中我們接收 CommonsMultipartFile對(duì)象時(shí)，有時(shí)會(huì)報(bào)這種異常：

org.springframework.beans.BeanInstantiationException: Could not instantiate bean class [org.springframework.web.multipart.commons.CommonsMultipartFile]: No default constructor found; nested exception is java.lang.NoSuchMethodException: org.springframework.web.multipart.commons.CommonsMultipartFile.<init>()

...

Caused by: java.lang.NoSuchMethodException: org.springframework.web.multipart.commons.CommonsMultipartFile.<init>()

這是因?yàn)樵诮邮?nbsp;CommonsMultipartFile 對(duì)象時(shí)，需要在對(duì)象前加 @RequestParam 注解 。

例：public void getFile(@RequestParam CommonsMultipartFile file){}

有時(shí)也會(huì)遇到這個(gè)異常：

Required CommonsMultipartFile parameter 'pic' is not present

這是因?yàn)樘砑?span style="box-sizing: border-box;">@RequestParam 注解 后，接收到空的 CommonsMultipartFile 對(duì)象 , 所以 CommonsMultipartFile 允許為 null，添加required=false 即可。

例：public void getFile(@RequestParam(required=false) CommonsMultipartFile file){}