Spring Boot Multipart文件上传报500内部服务器错误求助

问题描述 #

基于Maven构建的Spring Boot项目，实现文件上传接口时调用出现500 Internal Server Error。

错误信息 #

Request processing failed; nested exception is org.springframework.web.multipart.MultipartException: Failed to parse multipart servlet request; nested exception is java.lang.IllegalStateException: Unable to process parts as no multi-part configuration has been provided

原因分析 #

• 配置冲突：手动配置了Spring MVC的CommonsMultipartResolver，但Spring Boot默认使用StandardServletMultipartResolver，两者冲突导致Multipart配置未正确加载。
• 依赖冗余：pom.xml同时引入spring-webmvc和spring-boot-starter-web，后者已包含spring-webmvc，重复引入引发依赖混乱。
• 启动配置缺失：war打包的Spring Boot项目未正确继承SpringBootServletInitializer，导致容器无法识别Spring Boot的自动配置，包括Multipart配置。

解决方案 #

1. 清理冗余依赖 #

修改pom.xml，移除以下不必要的依赖：

<!-- 移除重复的spring-webmvc -->
<dependency>
    <groupId>org.springframework</groupId>
    <artifactId>spring-webmvc</artifactId>
    <version>5.2.21.RELEASE</version>
</dependency>
<!-- 移除commons-fileupload和commons-io，Spring Boot默认不需要 -->
<dependency>
    <groupId>commons-fileupload</groupId>
    <artifactId>commons-fileupload</artifactId>
    <version>1.3.1</version>
</dependency>
<dependency>
    <groupId>commons-io</groupId>
    <artifactId>commons-io</artifactId>
    <version>2.4</version>
</dependency>

2. 删除自定义MultipartResolver配置 #

修改SpringApplicationConfig.java，移除multipartResolver Bean的定义，让Spring Boot自动配置：

package awsarTest.config;

import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.config.annotation.EnableWebMvc;
import org.springframework.web.servlet.view.InternalResourceViewResolver;

@ComponentScan(basePackages = "awsarTest.controller")
@Configuration
@EnableWebMvc
public class SpringApplicationConfig {

    @Bean
    public InternalResourceViewResolver viewResolver() {
        InternalResourceViewResolver vw = new InternalResourceViewResolver();
        vw.setPrefix("/WEB-INF/jsp/");
        vw.setSuffix(".jsp");
        return vw;
    }

    // 移除下面的multipartResolver Bean
}

3. 添加Spring Boot启动类 #

如果项目没有启动类，创建一个继承SpringBootServletInitializer的启动类，适配war打包：

package awsarTest;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.web.servlet.support.SpringBootServletInitializer;

@SpringBootApplication
public class AwsarTestApplication extends SpringBootServletInitializer {
    public static void main(String[] args) {
        SpringApplication.run(AwsarTestApplication.class, args);
    }
}

4. 保留Multipart配置 #

application.properties中的Multipart配置可以继续使用，Spring Boot会自动读取并应用：

# MULTIPART (MultipartProperties)
# Enable multipart uploads
spring.servlet.multipart.enabled=true
# Threshold after which files are written to disk.
spring.servlet.multipart.file-size-threshold=2KB
# Max file size.
spring.servlet.multipart.max-file-size=200MB
# Max Request Size
spring.servlet.multipart.max-request-size=215MB

5. 验证Controller代码 #

确保Controller的上传方法参数正确，可修正方法名拼写（非必须，但更规范）：

@PostMapping(value = "/upload")
public String uploadDocument(@RequestParam("file") MultipartFile file) {
    String fileName = file.getOriginalFilename();
    System.out.println("Received file: " + fileName);        
    return fileName;
}

测试 #

重新打包部署项目，使用Postman调用接口http://localhost:6061/awsarTest/auth/upload，确保请求的Content-Type设置为multipart/form-data，并正确选择文件后发送请求。

内容的提问来源于stack exchange，提问作者Arunraj Chandran