springMVC REST 上传文件

参考：

1.http://www.journaldev.com/2573/spring-mvc-file-upload-example-single-multiple-files

上传接口controll：

@RestController
public class OcrController {
	
	private static final Logger logger = LoggerFactory.getLogger(OcrController.class);
	
	@Resource
	private OcrService ocrService;
	
	@RequestMapping(value="/api/ocr",method = RequestMethod.POST)
	public Response getOcrResponse(@RequestParam(value = "file", required = false) MultipartFile file ) {
		logger.info("get OCR services start...");
		
		OcrFailResponse ocrFailResponse = null;
		Response ocrResponse = null;
		
		File serverFile = createFileOnServer(file);
		
		if(serverFile.exists()){
			
			ocrResponse = ocrService.getOcrService(serverFile);
			return ocrResponse;
		}else{
			ocrFailResponse = new OcrFailResponse();
			ocrFailResponse.setCode(Response.RESULT_CODE_ERROR);
			ocrFailResponse.setMessage(OcrFailResponse.RESULT_MESSAGE_FILEUPLOAD_ERROR);
			return ocrFailResponse;
		}
		
	}
	
	
	public File createFileOnServer(MultipartFile file){
		
		File serverFile = null;
		
		if (!file.isEmpty()) {
			try {
				byte[] bytes = file.getBytes();

				// Creating the directory to store file
				String filename = "OcrUplaod_" + TimeUtil.genDate() + ".png";
				File dir = new File(SystemConfig.getFile_store_path());
				if (!dir.exists())
					dir.mkdirs();

				// Create the file on server
				serverFile = new File(dir.getAbsolutePath()
						+ File.separator + filename);
				BufferedOutputStream stream = new BufferedOutputStream(
						new FileOutputStream(serverFile));
				stream.write(bytes);
				stream.close();

				logger.info("Server File Location="
						+ serverFile.getAbsolutePath());
				
				

			} catch (Exception e) {
				logger.error("You failed to upload " + file + " => " + e.getMessage());
			}
		} else {
			logger.debug("You failed to upload " + file + " because the file was empty.");
		}
		
		return serverFile;
	}

}

注意要导入commons-fileupload.jar，要不会报错：

the current request is not a multipart request

compile 'commons-fileupload:commons-fileupload:1.3.2'

添加bean：

<bean id="multipartResolver"
		class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
	</bean>

这里可以配置文件上传大小限制：

<bean id="multipartResolver"
		class="org.springframework.web.multipart.commons.CommonsMultipartResolver">
		<property name="defaultEncoding" value="UTF-8"/>
        <property name="maxUploadSize" value="#{20*1024*1024}"/>
        <property name="resolveLazily" value="true"/>
	</bean>