Spring Boot文件上传大小限制问题及解决方案详解

org.apache.tomcat.util.http.fileupload.impl.FileSizeLimitExceededException: 
The field files exceeds its maximum permitted size of 1048576 bytes.

# 单个文件最大大小（这里设置为10MB）
spring.servlet.multipart.max-file-size=10MB
# 整个请求的最大大小（这里设置为20MB）
spring.servlet.multipart.max-request-size=20MB

spring:
  servlet:
    multipart:
      max-file-size: 10MB
      max-request-size: 20MB

import org.springframework.boot.web.servlet.MultipartConfigFactory;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.util.unit.DataSize;

import javax.servlet.MultipartConfigElement;

@Configuration
public class MultipartConfig {

    @Bean
    public MultipartConfigElement multipartConfigElement() {
        MultipartConfigFactory factory = new MultipartConfigFactory();
        // 单个文件大小限制（10MB）
        factory.setMaxFileSize(DataSize.ofMegabytes(10));
        // 总请求大小限制（20MB）
        factory.setMaxRequestSize(DataSize.ofMegabytes(20));
        return factory.createMultipartConfig();
    }
}

# 旧版本属性名
multipart.maxFileSize=10MB
multipart.maxRequestSize=20MB

<input type="file" name="files" accept=".jpg,.png,.pdf" max-size="10485760" multiple />

@PostMapping("/upload")
@ApiOperation(value = "渠道账号-文件上传", notes = "渠道账号-文件上传")
public Res<List<String>> uploadChannelFile(
        @RequestParam("files") MultipartFile[] files,
        @RequestParam("channelId") String channelId,
        @RequestParam("agentId") String agentId,
        @RequestParam("opUser") String opUser) {
    try {
        // 检查每个文件大小（10MB限制）
        for (MultipartFile file : files) {
            if (file.getSize() > 10 * 1024 * 1024) {
                return new Res<>(SupResultCode.CODE_900500, "文件大小不能超过10MB", null);
            }
        }
        
        List<String> docLinks = opmChannelAccountService.uploadChannelFiles(files, channelId, agentId, opUser);
        return new Res<>(ResultCode.CODE_000000, ResultCode.MSG_000000, docLinks);
    } catch (Exception e) {
        log.error("文件上传失败", e);
        return new Res<>(SupResultCode.CODE_900500, "文件上传失败: " + e.getMessage(), null);
    }
}

@ControllerAdvice
public class GlobalExceptionHandler {

    @ExceptionHandler(MaxUploadSizeExceededException.class)
    public ResponseEntity<String> handleMaxUploadSizeExceeded(MaxUploadSizeExceededException ex) {
        return ResponseEntity
                .status(HttpStatus.PAYLOAD_TOO_LARGE)
                .body("文件大小超过限制，请上传小于10MB的文件");
    }
}

@Async
public void processLargeFile(MultipartFile file) {
    // 处理大文件
}