Springboot+HTML5+Layui2.7.6上传文件【请求上传接口出现异常】-526互联

1.最近两天在springboot+html5项目中发现在用layui框架时报请求上传接口出现异常这个错误。

2.将代码全部整理了一遍，发现前端后台都没错！！！

但是还是【请求上传接口出现异常】，于是跑去翻看layui官网。

3.最终最终将错误锁定到了返回的JSON字符串中，我是返回的String，所以一直都会报【请求上传接口出现异常】。

4.可以在controller中将其返回成JSON字符串。

<1>首先我们要导入一个依赖

<!-- fast json-->
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.54</version>
</dependency>

<2>在controller中修改成上传成功返回JSON字符串

@PostMapping("/uploadFile")
    @ResponseBody
    public HashMap<String, Object> singleFileUpload(@RequestParam("file") MultipartFile file) {

        if (LOGGER.isDebugEnabled()) {
            LOGGER.debug("fileName = {}", file.getOriginalFilename());
        }
        try {
            if (file == null || NULL_FILE.equals(file.getOriginalFilename())) {
                // return "upload failure";
                return ResultMapUtil.getHashMapUploadFile("upload failure","500");
            }
            fileService.saveFile(file.getBytes(), uploadFolder, file.getOriginalFilename());
        } catch (Exception e) {
            // return "upload failure";
            return ResultMapUtil.getHashMapUploadFile("upload failure","500");
        }
        // return "upload success";
        return ResultMapUtil.getHashMapUploadFile("upload success","200");
    }

【注意：这一步中不同的人写的项目不同，controller也不相同，需要自己的根据实际情况来】

<3>给前端返回JSON格式数据

/**
 * 给前端返回的json格式数据
 */
public class ResultMapUtil {

    // 上传文件返回结果
    public static HashMap<String,Object> getHashMapUpload(String msg, String code){
        HashMap<String,Object> resultMap = new HashMap<>();
        resultMap.put("msg",msg);
        resultMap.put("code",code);
        if("200".equals(code)){
            resultMap.put("msg","success");
        }else {
            resultMap.put("msg","failure");
        }
        return resultMap;
    }

}

<4>文件上传service文件

@Service
@Transactional
public class FileServiceImpl implements FileService {

    private static final String UTF_8 = "UTF-8";

    @Value("${file.uploadFolder}")
    private String uploadFolder;

    @Override
    public void saveFile(byte[] file, String filePath, String fileName) throws Exception {
        File targetFile = new File(filePath);
        if (!targetFile.exists()) {
            targetFile.mkdirs();
        }
        FileOutputStream out = new FileOutputStream(filePath + fileName);
        out.write(file);
        out.flush();
        out.close();
    }
}

<5>文件上传service实现类文件

@Service
@Transactional
public class FileServiceImpl implements FileService {

    private static final String UTF_8 = "UTF-8";

    @Value("${file.uploadFolder}")
    private String uploadFolder;

    @Override
    public void saveFile(byte[] file, String filePath, String fileName) throws Exception {
        File targetFile = new File(filePath);
        if (!targetFile.exists()) {
            targetFile.mkdirs();
        }
        FileOutputStream out = new FileOutputStream(filePath + fileName);
        out.write(file);
        out.flush();
        out.close();
    }
}