SpringBoot中的multipartResolver上传文件配置

multipartResolver上传文件配置

1、gradle配置

   compile ('commons-io:commons-io:1.4')
   compile('commons-fileupload:commons-fileupload:1.2.1')

2、注册Bean

   @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);
       resolver.setMaxInMemorySize(40960);
       //上传文件大小 50M 50*1024*1024
       resolver.setMaxUploadSize(50*1024*1024);
       return resolver;
   }

SpringBoot MultipartResolver的坑

在使用springBoot上传文件的时候，我们会用到MultipartResolver。我看通过源码可以看到

@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;
}
@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;
}

可以看出MultipartAutoConfiguration配置类，默认加载的是StandardServletMultipartResolver。

然而，我们往往会在项目中加入commons-fileupload依赖，加载的是CommonsMultipartResolver。此时同时使用两个，会产生冲突。

解决方案

1、使用SpringBoot 默认的StandardServletMultipartResolver，不依赖commons-fileupload。

2、使用commons-fileupload的CommonsMultipartResolver，

排除默认

spring:
 autoconfigure:
   exclude: org.springframework.boot.autoconfigure.web.servlet.MultipartAutoConfiguration

自定义文件解析对象

   @Bean(name = "multipartResolver")
   public MultipartResolver multipartResolver() {
       CommonsMultipartResolver resolver = new CommonsMultipartResolver();
       resolver.setDefaultEncoding("UTF-8");
       return resolver;
   }

来源：https://blog.csdn.net/u011110968/article/details/82856736