Java上传文件、下载文件、预览文件

川长思鸟来 2024-03-24 10:12 81阅读 0赞

**目录**

一、上传文件

二、下载文件

三、预览文件

--------------------

#### 一、上传文件 ####

@PostMapping("/upload")
        public String uploadSystem(MultipartFile file){
            String url = "";
            try{
                String name = file.getOriginalFilename().substring(0,file.getOriginalFilename().indexOf(".")+ ".".length()-1);
                String imgName =name+"_"+ DateUtils.dateTimeNow();
    
                if (file == null) {
                    log.error("==>  没有上传文件。");
                    return ("没有上传文件。");
                }
                log.info("==>文件名: " + file.getOriginalFilename());
                url = fileService.handlerMultipartFile(file,imgName);
    
                log.info("==>文件路径: " + url);
            }
            catch (Exception e){
    
            }
    
            return url;
        }

#### 二、下载文件 ####

/**
         * 下载通用配置指导书
         * @param
         * @param response
         * @param filePath  文件路径
         */
    
        public void downloadInstruction(HttpServletResponse response, String filePath) {
    //        File file = new File(filePath);
            File file = new File(filePath);
            String fileName = file.getName();
            InputStream fis = null;
            try {
                fis = new FileInputStream(file);
                response.reset();
                response.setCharacterEncoding("UTF-8");
                response.setContentType("application/PDF;charset=utf-8");
                response.setHeader("content-disposition", "attachement;fileName=" + new String(fileName.getBytes("utf-8"), "ISO-8859-1"));
                byte[] bytes = new byte[1024];
                int len;
                while ((len = fis.read(bytes)) != -1) {
                    response.getOutputStream().write(bytes, 0, len);
                }
                response.flushBuffer();
                fis.close();
            } catch (IOException e) {
                throw new RuntimeException(e);
            }
    //        return "下载成功";
        }

#### 三、预览文件 ####

public void preview( HttpServletResponse response,String filePath) throws
                IOException {
            FileInputStream is = new FileInputStream(new File(filePath));
            // 清空response
            response.reset();
            //2、设置文件下载方式
            response.setCharacterEncoding("utf-8");
            response.setContentType("application/pdf");
            OutputStream outputStream = response.getOutputStream();
            int count = 0;
            byte[] buffer = new byte[1024 * 1024];
            while ((count = is.read(buffer)) != -1) {
                outputStream.write(buffer, 0, count);
            }
            outputStream.flush();
    
        }

FileService

package com.ruoyi.zw.controller;
    
    /**
     * @author: cyf
     * @Date: 2023/3/27 19:08
     */
    
    import com.ruoyi.common.config.RuoYiConfig;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.stereotype.Service;
    import org.springframework.web.multipart.MultipartFile;
    
    import java.io.File;
    import java.io.FileOutputStream;
    import java.io.OutputStream;
    
    @Service
    public class FileService {
        protected static final Logger logger= LoggerFactory.getLogger(FileService.class);
    
        private String directoryPath = RuoYiConfig.getFile();
    
        public FileService() {
            File directory = new File(directoryPath);
            if (!directory.exists()) {
                directory.mkdirs();
            }
        }
    
        public String handlerMultipartFile(MultipartFile multipartFile ,String unid) {
            String fileOldName = multipartFile.getOriginalFilename();
            int beginIndex = fileOldName.lastIndexOf(".");
            String suffix = fileOldName.substring(beginIndex);
            String newFileName =  unid+ suffix;
            File upFile = new File(directoryPath + "/" + newFileName);
            OutputStream outputStream = null;
            try {
                byte[] fileByte = multipartFile.getBytes();
                outputStream = new FileOutputStream(upFile);
                outputStream.write(fileByte);
                logger.info("<==  文件写出完成: " + newFileName);
                return  newFileName;
            } catch (Exception e) {
                logger.error("", e);
            } finally {
                try {
                    if (outputStream != null) {
                        outputStream.flush();
                        outputStream.close();
                    }
                } catch (Exception e) {
                    logger.error("", e);
                }
            }
            return  newFileName;
        }
    
    }