Java之图片上传与删除功能的实现

要实现Java图片上传与删除，并使本地和服务器上都能同时正常使用。

1.定义线上线下文件保存和显示路径

application-dev.properties

kapok.SHOW_PIC_PREFIX = http://localhost:8910/image/

#mac
#kapok.SAVE_PATH = /Users/luoyihao/images/

#win
kapok.SAVE_PATH = C:\\images\\

application-prod.properties

kapok.SHOW_PIC_PREFIX = http://xxxxx.com:8500/image/
kapok.SAVE_PATH = /projects/compositive-system/images/

2.在上面两个配置文件加上图片上传限制配置（不加则会报上传图片大小超出限制的错误）

spring.servlet.multipart.max-file-size = 5MB
spring.servlet.multipart.max-request-size = 20MB

3.在Controller导入配置变量

@Value("${kapok.SHOW_PIC_PREFIX}")
private String showPicPrefix;

@Value("${kapok.SAVE_PATH}")
private String savePath;

4.图片上传接口

@RequestMapping(value = "/uploadPic", method = RequestMethod.POST)
public Result uploadPic(@RequestParam("id") int id, @RequestParam("file") MultipartFile file) {
    if (file == null || file.isEmpty()) {
        return ResultGenerator.genFailResult("上传文件为空");
    }

    String fileName = file.getOriginalFilename();
    List<String> FILE_WHILE_EXT_LIST = Arrays.asList("JPG", "PNG", "JPEG", "GIF");
    String fileExtName = fileName.substring(fileName.lastIndexOf(".") + 1);
    if (FILE_WHILE_EXT_LIST.contains(fileExtName.toUpperCase())) {
        String newFileName = UUID.randomUUID() + "." + fileExtName;
        File dest = new File(savePath + newFileName);
        if(!dest.getParentFile().exists()){
            dest.getParentFile().mkdirs();
        }
        try {
            file.transferTo(dest);
            PointsExchange pointsExchange = pointsExchangeService.getById(id);
            pointsExchange.setPic(newFileName);
            pointsExchangeService.updateById(pointsExchange);
            return ResultGenerator.genSuccessResult();
        } catch (IOException e) {
            e.printStackTrace();
            return ResultGenerator.genFailResult("上传失败");
        }
    }
    return ResultGenerator.genFailResult("图片格式不正确");
}

5.图片删除接口

@RequestMapping(value = "/delPic", method = RequestMethod.POST)
public Result delPic(@RequestBody PointsExchange pointsExchange) {
    File file = new File(savePath + pointsExchange.getPic());

    PointsExchange pe = pointsExchangeService.getById(pointsExchange.getId());
    pe.setPic(Constants.DEFAULT_IMG);
    pointsExchangeService.updateById(pe);

    //判断文件存不存在
    if (!file.exists()) {
        return ResultGenerator.genFailResult("删除文件失败：" + pointsExchange.getPic() + "不存在！");
    } else if (Constants.DEFAULT_IMG.equals(pointsExchange.getPic())) {
        return ResultGenerator.genFailResult("该奖品没有图片");
    } else {
        //判断这是不是一个文件，ps：有可能是文件夹
        if (file.isFile()) {
            boolean res = file.delete();
            return ResultGenerator.genSuccessResult(res);
        }
    }
    return ResultGenerator.genFailResult("删除文件失败");
}

6.图片展示接口

@RequestMapping(value = "/list", method = RequestMethod.GET)
public Result list(@RequestParam(defaultValue = "0") Integer page, @RequestParam(defaultValue = "0") Integer size) {
    PageHelper.startPage(page, size);
    QueryWrapper qw = new QueryWrapper();
    qw.orderByAsc("points");
    List<PointsExchange> list = pointsExchangeService.list(qw);
    for (PointsExchange pe:list){
        pe.setPic(showPicPrefix + pe.getPic());
    }
    PageInfo pageInfo = new PageInfo(list);
    return ResultGenerator.genSuccessResult(pageInfo);
}

7.给继承自WebMvcConfigurationSupport的KapokWebMvcConfigurer类的addResourceHandlers方法增加一条语句

作用：将启动的服务上的/images/作为虚拟路径，映射到真实的图片保存路径，用于图片展示。

registry.addResourceHandler("/image/**").addResourceLocations("file:"+savePath+"/");

8.如果是用Docker部署，部署的时候要给docker run命令加上 -v 服务器真实目录:容器内部目录，实现文件夹的挂载，同步两边的文件。

docker run -d -p 8005:8910 -v /projects/compositive-system/images:/projects/compositive-system/images compositive-system

9.前端增加图片上传按钮

<a-upload
  v-model:file-list="fileList"
  name="file"
  :headers="headers"
  :action="url"
  :before-upload="(file) => beforeUpload(file, record)"
  :showUploadList="false"
  @change="handleChange"
>
  <a-button type="primary">
    <upload-outlined></upload-outlined>
    上传图片
  </a-button>
</a-upload>

10.前端图片上传JS

const url = ref("");
const beforeUpload = (file, record) => {
  url.value =
    import.meta.env.VITE_APP_BASE_API +
    "/pointsexchange/uploadPic?id=" +
    record.id;
};

const fileList = ref([]);

const handleChange = (info) => {
  if (info.file.status !== "uploading") {
    console.log(info.file, info.fileList);
  }
  if (info.file.status === "done") {
    console.log("info", info);
    if (info.file.response.code == 200) {
      message.success(`${info.file.name}上传成功`);
      query();
    } else {
      message.error(info.file.response.message);
    }
  } else if (info.file.status === "error") {
    message.error(`${info.file.name}上传失败`);
  }
};

const headers = {
  Authorization: getToken(),
  "trace-id": uuid.v1(),
  "trace-user": store.getters.userid,
};

11.前端增加删除图片按钮

<a-button type="primary" danger @click="delPic(record)">
  <template #icon>
    <delete-outlined />
  </template>
  删除图片
</a-button>

12.前端图片删除JS

// 删除图片
const delPic = (row) => {
  const modal = Modal.confirm();
  modal.update({
    title: "确认删除该图片吗?",
    icon: createVNode(ExclamationCircleOutlined),
    content: "",
    okText: "删除",
    okType: "danger",
    cancelText: "取消",
    closable: true,
    maskClosable: true,
    onOk(e) {
      const param = Object.assign({}, row);
      PointsExchangeApi.delPic(param)
        .then((response) => {
          const data = response.data;
          console.log(response);
          if (data.code === 200) {
            message.success("删除成功");
          } else {
            message.warning(data.message);
          }
          query();
          modal.destroy();
        })
        .catch((error) => {
          query();
        });
    },
    onCancel() {
      console.log("Cancel");
      modal.destroy();
    },
  });
};

13.前端图片展示（404的时候显示默认图片）

<img :src="item.pic" alt="" class="img" onerror="this.src='../src/assets/default.png'"/>

14.Nginx配置

如果在线上出现大图片无法上传的情况，则是Nginx对图片传输做了限制，默认限制图片上传大小为1M。

解决方法：在nginx.conf的http对象增加配置（设置为5M）

client_max_body_size 5m;

即可。