本文主要是介绍用cn.hutool工具包进行图片上传下载示例，对大家解决编程问题具有一定的参考价值，需要的程序猿们随着小编来一起学习吧！

文章目录

• 实体类
• controller
• service
• • 数据转换的工具类
  • file工具类

Hutool-http针对JDK的HttpUrlConnection做一层封装，简化了HTTPS请求、文件上传、Cookie记忆等操作，使Http请求变得无比简单。
用的是smms图床。
依赖：

        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.7.12</version>
        </dependency>

实体类

@Data
public class PictureDto implements Serializable {

    /** ID */
    private Long id;

    /** 上传日期 */
    private Timestamp createTime;

    /** 删除的URL */
    private String deleteUrl;

    /** 图片名称 */
    private String filename;

    /** 图片高度 */
    private String height;

    /** 图片大小 */
    private String size;

    /** 图片地址 */
    private String url;

    /** 用户名称 */
    private String username;

    /** 图片宽度 */
    private String width;

    /** 文件的MD5值 */
    private String md5code;
}

controller

@RestController
@RequestMapping("/api/pictures")
@Api(tags = "工具：免费图床管理")
public class PictureController {
    private final IGenerator generator;
    private final PictureService pictureService;

    public PictureController(IGenerator generator, PictureService pictureService) {
        this.generator = generator;
        this.pictureService = pictureService;
    }

    @Log("查询图片")
    @PreAuthorize("@el.check('pictures:list')")
    @GetMapping
    @ApiOperation("查询图片")
    public ResponseEntity<Object> getRoles(PictureQueryCriteria criteria, Pageable pageable) {
        return new ResponseEntity<>(pictureService.queryAll(criteria, pageable), HttpStatus.OK);
    }

    @Log("导出数据")
    @ApiOperation("导出数据")
    @GetMapping(value = "/download")
    @PreAuthorize("@el.check('pictures:list')")
    public void download(HttpServletResponse response, PictureQueryCriteria criteria) throws IOException {
        pictureService.download(generator.convert(pictureService.queryAll(criteria), PictureDto.class), response);
    }

    @Log("上传图片")
    @PreAuthorize("@el.check('pictures:add')")
    @PostMapping
    @ApiOperation("上传图片")
    public ResponseEntity<Object> upload(@RequestParam MultipartFile file) {
        String userName = SecurityUtils.getUsername();
        Picture picture = pictureService.upload(file, userName);
        return new ResponseEntity<>(picture, HttpStatus.OK);
    }

    @Log("同步图床数据")
    @ApiOperation("同步图床数据")
    @PostMapping(value = "/synchronize")
    public ResponseEntity<Object> synchronize() {
        pictureService.synchronize();
        return new ResponseEntity<>(HttpStatus.OK);
    }

    @Log("多选删除图片")
    @ApiOperation("多选删除图片")
    @PreAuthorize("@el.check('pictures:del')")
    @DeleteMapping
    public ResponseEntity<Object> deleteAll(@RequestBody Long[] ids) {
        pictureService.deleteAll(ids);
        return new ResponseEntity<>(HttpStatus.OK);
    }
}

service

package co.yixiang.tools.service.impl;

import cn.hutool.http.HttpRequest;
import cn.hutool.http.HttpUtil;
import cn.hutool.json.JSONObject;
import cn.hutool.json.JSONUtil;
import co.yixiang.common.service.impl.BaseServiceImpl;
import co.yixiang.common.utils.QueryHelpPlus;
import co.yixiang.dozer.service.IGenerator;
import co.yixiang.exception.BadRequestException;
import co.yixiang.tools.domain.Picture;
import co.yixiang.tools.service.PictureService;
import co.yixiang.tools.service.dto.PictureDto;
import co.yixiang.tools.service.dto.PictureQueryCriteria;
import co.yixiang.tools.service.mapper.PictureMapper;
import co.yixiang.utils.FileUtil;
import co.yixiang.utils.TranslatorUtil;
import co.yixiang.utils.ValidationUtil;
import co.yixiang.utils.YshopConstant;
import com.alibaba.fastjson.JSON;
import com.baomidou.mybatisplus.core.conditions.query.LambdaQueryWrapper;
import com.github.pagehelper.PageInfo;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.data.domain.Pageable;
import org.springframework.stereotype.Service;
import org.springframework.transaction.annotation.Propagation;
import org.springframework.transaction.annotation.Transactional;
import org.springframework.web.multipart.MultipartFile;

import javax.servlet.http.HttpServletResponse;
import java.io.File;
import java.io.IOException;
import java.util.*;

// 默认不使用缓存
//import org.springframework.cache.annotation.CacheConfig;
//import org.springframework.cache.annotation.CacheEvict;
//import org.springframework.cache.annotation.Cacheable;

/**
 * @author hupeng
 * @date 2020-05-13
 */
@Service
//@AllArgsConstructor
//@CacheConfig(cacheNames = "picture")
@Transactional(propagation = Propagation.SUPPORTS, readOnly = true, rollbackFor = Exception.class)
public class PictureServiceImpl extends BaseServiceImpl<PictureMapper, Picture> implements PictureService {

    private final IGenerator generator;
// IGenerator是一个自定义的数据转化接口
    @Value("${smms.token}")
    private String token;//是用于图床上传文件的token
//在yml文件中配置：
//# sm.ms 图床的 token
//smms:
//  token: 1oOP3ykFDI0K6ifmtvU7c8Y1eTWZSlyl

    private static final String SUCCESS = "success";

    private static final String CODE = "code";

    private static final String MSG = "message";

    public PictureServiceImpl(IGenerator generator) {
        this.generator = generator;
    }

    @Override
    //@Cacheable
    public Map<String, Object> queryAll(PictureQueryCriteria criteria, Pageable pageable) {
        getPage(pageable);
        PageInfo<Picture> page = new PageInfo<>(queryAll(criteria));
        Map<String, Object> map = new LinkedHashMap<>(2);
        map.put("content", generator.convert(page.getList(), PictureDto.class));
        map.put("totalElements", page.getTotal());
        return map;
    }


    @Override
    //@Cacheable
    public List<Picture> queryAll(PictureQueryCriteria criteria) {
        return baseMapper.selectList(QueryHelpPlus.getPredicate(Picture.class, criteria));
    }


    @Override
    public void download(List<PictureDto> all, HttpServletResponse response) throws IOException {
        List<Map<String, Object>> list = new ArrayList<>();
        for (PictureDto picture : all) {
            Map<String, Object> map = new LinkedHashMap<>();
            map.put("上传日期", picture.getCreateTime());
            map.put("删除的URL", picture.getDeleteUrl());
            map.put("图片名称", picture.getFilename());
            map.put("图片高度", picture.getHeight());
            map.put("图片大小", picture.getSize());
            map.put("图片地址", picture.getUrl());
            map.put("用户名称", picture.getUsername());
            map.put("图片宽度", picture.getWidth());
            map.put("文件的MD5值", picture.getMd5code());
            list.add(map);
        }
        FileUtil.downloadExcel(list, response);
    }

    @Override
    @Transactional(rollbackFor = Throwable.class)
    public Picture upload(MultipartFile multipartFile, String username) {
        File file = FileUtil.toFile(multipartFile);
        // 验证是否重复上传
        Picture picture = this.getOne(new LambdaQueryWrapper<Picture>().eq(Picture::getMd5code, FileUtil.getMd5(file)));
        if (picture != null) {
            return picture;
        }
        HashMap<String, Object> paramMap = new HashMap<>(1);
        paramMap.put("smfile", file);
        // 上传文件
        String result = HttpRequest.post(YshopConstant.Url.SM_MS_URL + "/v2/upload")
                .header("Authorization", token)
                .form(paramMap)//设置map类型表单数据

                .timeout(20000)
                .execute().body();//获取响应主体
        JSONObject jsonObject = JSONUtil.parseObj(result);
        if (!jsonObject.get(CODE).toString().equals(SUCCESS)) {
            throw new BadRequestException(TranslatorUtil.translate(jsonObject.get(MSG).toString()));
        }
        picture = JSON.parseObject(jsonObject.get("data").toString(), Picture.class);
        picture.setSize(FileUtil.getSize(Integer.parseInt(picture.getSize())));
        picture.setUsername(username);
        picture.setMd5code(FileUtil.getMd5(file));
        picture.setFilename(FileUtil.getFileNameNoEx(multipartFile.getOriginalFilename()) + "." + FileUtil.getExtensionName(multipartFile.getOriginalFilename()));
        this.save(picture);
        //删除临时文件
        FileUtil.del(file);
        // FileUtil是PathUtil的子类 是cn.hutool.core.io包下
        return picture;

    }

    @Override
    public Picture findById(Long id) {
        Picture picture = this.getById(id);
        ValidationUtil.isNull(picture.getId(), "Picture", "id", id);
        return picture;
    }

    @Override
    public void deleteAll(Long[] ids) {
        for (Long id : ids) {
            Picture picture = findById(id);
            try {
                HttpUtil.get(picture.getDeleteUrl());
                this.removeById(id);
            } catch (Exception e) {
                this.removeById(id);
            }
        }
    }

    @Override
    public void synchronize() {
        //链式构建请求
        //Hutool-http针对JDK的HttpUrlConnection做一层封装，简化了HTTPS请求、文件上传、Cookie记忆等操作，使Http请求变得无比简单
        String result = HttpRequest.get(YshopConstant.Url.SM_MS_URL + "/v2/upload_history")
                //头信息，多个头信息多次调用此方法即可
                .header("Authorization", token)
                .timeout(20000)
                .execute().body();
        JSONObject jsonObject = JSONUtil.parseObj(result);
        List<Picture> pictures = JSON.parseArray(jsonObject.get("data").toString(), Picture.class);
        for (Picture picture : pictures) {
            if (this.getOne(new LambdaQueryWrapper<Picture>().eq(Picture::getUrl, picture.getUrl())) == null) {
                picture.setSize(FileUtil.getSize(Integer.parseInt(picture.getSize())));
                picture.setUsername("System Sync");
                picture.setMd5code(null);
                this.save(picture);
            }
        }
    }
}

数据转换的工具类

public interface IGenerator {

    /**
     * 转换
     *
     * @param s   数据对象
     * @param clz 复制目标类型
     * @return {@link T}
     * @Description: 单个对象的深度复制及类型转换，vo/domain , po
     * @author banjuer@outlook.com
     * @Time 2018年5月9日 下午3:53:24
     */
    <T, S> T convert(S s, Class<T> clz);
    /**
     * 转换
     * @param s   数据对象
     * @param clz 复制目标类型
     * @return {@link List<T>}
     * @Description: list深度复制
     * @author banjuer@outlook.com
     * @Time 2018年5月9日 下午3:54:08
     */
    <T, S> List<T> convert(List<S> s, Class<T> clz);
}
@Component
@Lazy(true)
public class EJBGenerator implements IGenerator {

    @Autowired
    protected Mapper dozerMapper;
    //Mapper 是org.dozer包下的

    @Override
    public <T, S> T convert(final S s, Class<T> clz) {
        return s == null ? null : this.dozerMapper.map(s, clz);
    }
     @Override
    public <T, S> List<T> convert(List<S> s, Class<T> clz) {
        return s == null ? null : s.stream().map(vs -> this.dozerMapper.map(vs, clz)).collect(Collectors.toList());
    }
}

file工具类

/**
 * File工具类，扩展 hutool 工具包
 * @author Zheng Jie
 * @date 2018-12-27
 */
public class FileUtil extends cn.hutool.core.io.FileUtil {

    /**
     * 定义GB的计算常量
     */
    private static final int GB = 1024 * 1024 * 1024;
    /**
     * 定义MB的计算常量
     */
    private static final int MB = 1024 * 1024;
    /**
     * 定义KB的计算常量
     */
    private static final int KB = 1024;

    /**
     * 格式化小数
     */
    private static final DecimalFormat DF = new DecimalFormat("0.00");

    /**
     * MultipartFile转File
     */
    public static File toFile(MultipartFile multipartFile) {
        // 获取文件名
        String fileName = multipartFile.getOriginalFilename();
        // 获取文件后缀
        String prefix = "." + getExtensionName(fileName);
        File file = null;
        try {
            // 用uuid作为文件名，防止生成的临时文件重复
            file = File.createTempFile(IdUtil.simpleUUID(), prefix);
            // MultipartFile to File
            multipartFile.transferTo(file);
        } catch (IOException e) {
            e.printStackTrace();
        }
        return file;
    }

    /**
     * 获取文件扩展名，不带 .
     */
    public static String getExtensionName(String filename) {
        if ((filename != null) && (filename.length() > 0)) {
            int dot = filename.lastIndexOf('.');
            if ((dot > -1) && (dot < (filename.length() - 1))) {
                return filename.substring(dot + 1);
            }
        }
        return filename;
    }

    /**
     * Java文件操作 获取不带扩展名的文件名
     */
    public static String getFileNameNoEx(String filename) {
        if ((filename != null) && (filename.length() > 0)) {
            int dot = filename.lastIndexOf('.');
            if ((dot > -1) && (dot < (filename.length()))) {
                return filename.substring(0, dot);
            }
        }
        return filename;
    }

    /**
     * 文件大小转换
     */
    public static String getSize(long size) {
        String resultSize;
        if (size / GB >= 1) {
            //如果当前Byte的值大于等于1GB
            resultSize = DF.format(size / (float) GB) + "GB   ";
        } else if (size / MB >= 1) {
            //如果当前Byte的值大于等于1MB
            resultSize = DF.format(size / (float) MB) + "MB   ";
        } else if (size / KB >= 1) {
            //如果当前Byte的值大于等于1KB
            resultSize = DF.format(size / (float) KB) + "KB   ";
        } else {
            resultSize = size + "B   ";
        }
        return resultSize;
    }
 /**
     * 将文件名解析成文件的上传路径
     */
    public static File upload(MultipartFile file, String filePath) {
        //String name = getFileNameNoEx(file.getOriginalFilename());
        String suffix = getExtensionName(file.getOriginalFilename());
        StringBuffer nowStr = fileRename();
        try {
            String fileName = nowStr + "." + suffix;
            String path = filePath + fileName;
            // getCanonicalFile 可解析正确各种路径
            File dest = new File(path).getCanonicalFile();
            // 检测是否存在目录
            if (!dest.getParentFile().exists()) {
                dest.getParentFile().mkdirs();
            }
            // 文件写入
            file.transferTo(dest);
            return dest;
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
 /**
     * 导出excel
     */
    public static void downloadExcel(List<Map<String, Object>> list, HttpServletResponse response) throws IOException {
        String tempPath = System.getProperty("java.io.tmpdir") + IdUtil.fastSimpleUUID() + ".xlsx";
        File file = new File(tempPath);
        BigExcelWriter writer = ExcelUtil.getBigWriter(file);
        // 一次性写出内容，使用默认样式，强制输出标题
        writer.write(list, true);
        //response为HttpServletResponse对象
        response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet;charset=utf-8");
        //test.xls是弹出下载对话框的文件名，不能为中文，中文请自行编码
        response.setHeader("Content-Disposition", "attachment;filename=file.xlsx");
        ServletOutputStream out = response.getOutputStream();
        // 终止后删除临时文件
        file.deleteOnExit();
        writer.flush(out, true);
        //此处记得关闭输出Servlet流
        IoUtil.close(out);
    }

    public static String getFileType(String type) {
        String documents = "txt doc pdf ppt pps xlsx xls docx";
        String music = "mp3 wav wma mpa ram ra aac aif m4a";
        String video = "avi mpg mpe mpeg asf wmv mov qt rm mp4 flv m4v webm ogv ogg";
        String image = "bmp dib pcp dif wmf gif jpg tif eps psd cdr iff tga pcd mpt png jpeg";
        if (image.contains(type)) {
            return "pic";
        } else if (documents.contains(type)) {
            return "txt";
        } else if (music.contains(type)) {
            return "music";
        } else if (video.contains(type)) {
            return "vedio";
        } else {
            return "other";
        }
    }


    public static void checkSize(long maxSize, long size) {
        // 1M
        int len = 1024 * 1024;
        if (size > (maxSize * len)) {
            throw new BadRequestException("文件超出规定大小");
        }
    }

    /**
     * 判断两个文件是否相同
     */
    public static boolean check(File file1, File file2) {
        String img1Md5 = getMd5(file1);
        String img2Md5 = getMd5(file2);
        return img1Md5.equals(img2Md5);
    }

    /**
     * 判断两个文件是否相同
     */
    public static boolean check(String file1Md5, String file2Md5) {
        return file1Md5.equals(file2Md5);
    }

    private static byte[] getByte(File file) {
        // 得到文件长度
        byte[] b = new byte[(int) file.length()];
        try {
            InputStream in = new FileInputStream(file);
            try {
                in.read(b);
            } catch (IOException e) {
                e.printStackTrace();
            }
        } catch (FileNotFoundException e) {
            e.printStackTrace();
            return null;
        }
        return b;
    }

    private static String getMd5(byte[] bytes) {
        // 16进制字符
        char[] hexDigits = {'0', '1', '2', '3', '4', '5', '6', '7', '8', '9', 'a', 'b', 'c', 'd', 'e', 'f'};
        try {
            MessageDigest mdTemp = MessageDigest.getInstance("MD5");
            mdTemp.update(bytes);
            byte[] md = mdTemp.digest();
            int j = md.length;
            char[] str = new char[j * 2];
            int k = 0;
            // 移位 输出字符串
            for (byte byte0 : md) {
                str[k++] = hexDigits[byte0 >>> 4 & 0xf];
                str[k++] = hexDigits[byte0 & 0xf];
            }
            return new String(str);
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }

    /**
     * 下载文件
     * @param request /
     * @param response /
     * @param file /
     */
    public static void downloadFile(HttpServletRequest request, HttpServletResponse response, File file, boolean deleteOnExit) {
        response.setCharacterEncoding(request.getCharacterEncoding());
        response.setContentType("application/octet-stream");
        FileInputStream fis = null;
        try {
            fis = new FileInputStream(file);
            response.setHeader("Content-Disposition", "attachment; filename=" + file.getName());
            IOUtils.copy(fis, response.getOutputStream());
            response.flushBuffer();
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            if (fis != null) {
                try {
                    fis.close();
                    if (deleteOnExit) {
                        file.deleteOnExit();
                    }
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }

    public static String getMd5(File file) {
        return getMd5(getByte(file));
    }

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