文件下载实例

冷不防 2022-12-02 13:41 156阅读 0赞

在开发工作中遇到文件下载内容，记录下来

## 后台代码： ##

import java.io.ByteArrayInputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.math.BigDecimal;
    import java.text.SimpleDateFormat;
    import java.util.Base64;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.transaction.annotation.Transactional;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.multipart.MultipartFile;
    import org.springframework.web.multipart.MultipartHttpServletRequest;
    import org.springframework.web.util.WebUtils;
    
    
    
    @RestController
    @Transactional
    @RequestMapping("/upload")
    public class UploadController { 
    	@Autowired
    	public UploadService service;
    	@Autowired
    	public FileType fileType;
    
    	@Value("${upload.path:{#/opt/data/upload}}")
    	private String basepath;
    
    	@Value("${file.endstr}")
    	private String endstr;
    
    	private IIdentityService ident = AdapterFactory.getIdentityService();
    
    	@RequestMapping(value = "/test", method = RequestMethod.GET)
    	public String test() { 
    		return "1234567890";
    	}
    
    	@RequestMapping(value = "/upload", method = {  RequestMethod.GET, RequestMethod.POST })
    	// @PathVariable("tableName")String tableName,@RequestParam("file")
    	// MultipartFile file
    	public Map<String, Object> upload(HttpServletRequest request) { 
    
    		OutputStream out = null;
    		InputStream is = null;
    		Map<String, Object> result = new HashMap<String, Object>();
    
    		String tableName = request.getParameter("tableName");
    		String id = request.getParameter("pkVal");
    		String name = request.getParameter("colName");
    		String fileTypes = request.getParameter("fileType");
    
    		String contentType = request.getContentType();
    		if (contentType == null || !contentType.toLowerCase().startsWith("multipart/")) { 
    			result.put("code", 500);
    			result.put("msg", "文件不存在或者文件内容为空");
    			return result;
    		}
    
    		MultipartHttpServletRequest multipartRequest = WebUtils.getNativeRequest(request,
    				MultipartHttpServletRequest.class);
    		MultipartFile file = multipartRequest.getFile("file");
    		// 判断文件是否存在
    		if (file.isEmpty()) { 
    			result.put("code", 500);
    			result.put("msg", "文件不存在");
    			return result;
    		}
    		String fileName = file.getOriginalFilename();
    
    		String substring = fileName.substring(fileName.indexOf(".") + 1, fileName.length());
    
    		// 自定义路径
    		SimpleDateFormat fm = new SimpleDateFormat("yyyyMMdd");
    		SimpleDateFormat fm2 = new SimpleDateFormat("yyyyMMddHHmmss");
    		String filePath = File.separator + "upload" + File.separator + fm.format(new Date()) + File.separator
    				+ fm2.format(new Date()) + "." + substring;
    		File dest = new File(basepath + filePath);
    		if (!dest.getParentFile().exists()) { 
    			dest.getParentFile().mkdirs();
    		}
    
    		try { 
    			byte[] bytes = file.getBytes();
    			out = new FileOutputStream(dest);
    			is = new ByteArrayInputStream(bytes);
    			byte[] buff = new byte[1024];
    			int len = 0;
    			while ((len = is.read(buff)) != -1) { 
    				out.write(buff, 0, len);
    			}
    			is.close();
    			out.close();
    			// 验证文件类型
    			fileType.getAllFileType();//加载文件类型
    			String fileType = FileType.getFileType(dest);
    
    			if (checkType(fileType.substring(fileType.indexOf("+") + 1))) { 
    				if (dest.delete()) { 
    					result.put("msg2", "文件删除成功");
    				}
    				;
    				result.put("code", 500);
    				result.put("msg", "文件类型不符");
    				return result;
    			}
    
    			// 保存上传信息
    			UploadFileInformation infor = new UploadFileInformation();
    			infor.setMain_table(tableName);// 主记录表名
    			infor.setMain_id(id);// 主记录id
    
    			infor.setFile_name(fileName);// 文件名称
    			infor.setFile_id(filePath);// 文件标识路径
    			infor.setSmall_id(filePath);// 缩略图标识路径
    			infor.setMain_field(name);// 主记录字段名称
    
    			infor.setFile_type(fileTypes == null ? "图片" : fileTypes);// 文件类型
    			infor.setReg_date(new Date());// 登记时间
    
    			double size = file.getSize();
    			double kilobytes = (size / 1024);
    			double megabytes = (kilobytes / 1024);
    			infor.setAtt_size(new BigDecimal(String.format("%.2f", megabytes)));// 文件大小
    
    			// 人员信息 TODO
    			String reg_staff_id = null;
    			String reg_staff_name = null;
    			String iscUserId = null;
    			if (iscUserId == null) { 
    				iscUserId = (String) request.getAttribute("user_id");
    			}
    			if (null == iscUserId || ("").equals(iscUserId) || iscUserId.equals("null")) { 
    				reg_staff_id = "1";
    				reg_staff_name = "2";
    			} else { 
    				String userinfo[] = iscUserId.split(":");
    				List<User> users = ident.getUserByIds(new String[] {  userinfo[0] });
    				reg_staff_name = users.get(0).getName();
    				reg_staff_id = users.get(0).getId();
    			}
    			infor.setReg_staff_id(reg_staff_id);
    			infor.setReg_staff_name(reg_staff_name);
    
    			// infor.setATT_FILE(new Byte("99"));//数据库存储功能的存储字段
    			service.uploadFileInformation(infor);
    
    			result.put("code", 200);
    			result.put("msg", "文件上传成功");
    			return result;
    		} catch (Exception e) { 
    			e.printStackTrace();
    			result.put("code", 500);
    			result.put("msg", "文件上传失败");
    			return result;
    		}
    	}
    
    	private boolean checkType(String substring) { 
    		boolean open = false;
    		
    		if("null".equals(substring)){ 
    			open = true;
    		}
    		return open;
    	}
    
    	@RequestMapping(value = "/download", method = RequestMethod.GET)
    	public Map<String, Object> download(HttpServletRequest request, HttpServletResponse response,
    			@RequestParam("tableName") String tableName, @RequestParam("pkVal") String pkVal,
    			@RequestParam("colName") String colName) { 
    		UploadFileInformation infor = new UploadFileInformation();
    		infor.setMain_table(tableName);
    		infor.setMain_id(pkVal);
    		infor.setMain_field(colName);
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 500);
    		result.put("result", "");
    		result.put("msg", "下载失败");
    		infor = service.findOneByTABLE_NAMEAndPK_VALAndCOL_NAME(infor);
    		if (infor == null) { 
    			return result;
    		}
    		String fileName = infor.getFile_name();
    		result.put("fileName", fileName);
    		File file = new File(basepath + infor.getFile_id());
    
    		FileInputStream inputFile = null;
    		String base64 = null;
    
    		try { 
    			inputFile = new FileInputStream(file);
    			byte[] buffer = new byte[(int) file.length()];
    			byte[] bytes = new byte[inputFile.available()];
    			int length = inputFile.read(bytes);
    			base64 = Base64.getEncoder().encodeToString(bytes);
    			result.put("code", 200);
    			result.put("result", "data:text/xml;base64," + base64);
    			result.put("msg", "");
    			return result;
    		} catch (FileNotFoundException e) { 
    			e.printStackTrace();
    		} catch (IOException e) { 
    			e.printStackTrace();
    		} finally { 
    			try { 
    				if (inputFile != null) { 
    					inputFile.close();
    				}
    			} catch (IOException e) { 
    				e.printStackTrace();
    			}
    		}
    		result.put("msg", "下载失败。。。");
    		return result;
    	}
    
    	@RequestMapping(value = "/show", method = RequestMethod.GET)
    	public Map<String, Object> show(HttpServletRequest request, HttpServletResponse response,
    			@RequestParam("tableName") String tableName, @RequestParam("pkVal") String pkVal,
    			@RequestParam("colName") String colName) { 
    		UploadFileInformation infor = new UploadFileInformation();
    		infor.setMain_table(tableName);
    		infor.setMain_id(pkVal);
    		infor.setMain_field(colName);
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 500);
    		result.put("result", "");
    		result.put("msg", "预览错误");
    		infor = service.findOneByTABLE_NAMEAndPK_VALAndCOL_NAME(infor);
    		if (infor == null) { 
    			return result;
    		}
    		String fileName = infor.getFile_name();
    		File file = new File(basepath + infor.getFile_id());
    
    		FileInputStream inputFile = null;
    		String base64 = null;
    
    		try { 
    			inputFile = new FileInputStream(file);
    			byte[] buffer = new byte[(int) file.length()];
    			byte[] bytes = new byte[inputFile.available()];
    			int length = inputFile.read(bytes);
    			base64 = Base64.getEncoder().encodeToString(bytes);
    			result.put("code", 200);
    			result.put("result", "data:text/xml;base64," + base64);
    			result.put("msg", "");
    			return result;
    		} catch (FileNotFoundException e) { 
    			e.printStackTrace();
    		} catch (IOException e) { 
    			e.printStackTrace();
    		} finally { 
    			try { 
    				if (inputFile != null) { 
    					inputFile.close();
    				}
    			} catch (IOException e) { 
    				e.printStackTrace();
    			}
    		}
    		result.put("msg", "预览错误。。。");
    		return result;
    	}
    
    	/** * 根据id 类型 返回所有信息 * @param mainId id * @param type 文件类型 * @param isReturnFile 是否返回64 1 ：返回 * @return */
    	@RequestMapping(value = "/findbymainidandtype", method = RequestMethod.GET)
    	public Map<String, Object> findbymainidandtype(
    			@RequestParam("mainId") String mainId,
    			@RequestParam("type") String type,
    			@RequestParam("isReturnFile") String isReturnFile
    			) { 
    		List<UploadFileInformation> data = service.findbymainid(mainId,type);
    		
    		if("1".equals(isReturnFile)){ 
    			for (UploadFileInformation uploadFileInformation : data) { 
    				String base64 = toBase64(uploadFileInformation);
    				uploadFileInformation.setImg_base64(base64);
    			}
    		}
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 200);
    		result.put("data", data);
    		result.put("msg", "");
    		return result;
    
    	}
    	/** * 根据 主记录ID 查询所有的信息 * * @param mainId * @return */
    	@RequestMapping(value = "/findbymainid", method = RequestMethod.GET)
    	public Map<String, Object> findbymainid(
    			@RequestParam("mainId") String mainId) { 
    		List<UploadFileInformation> data = service.findbymainid(mainId,null);
    		
    		for (UploadFileInformation uploadFileInformation : data) { 
    			String base64 = toBase64(uploadFileInformation);
    			uploadFileInformation.setImg_base64(base64);
    		}
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 200);
    		result.put("data", data);
    		result.put("msg", "");
    		return result;
    
    	}
    	
    	private String toBase64 (UploadFileInformation infor){ 
    		File file = new File(basepath + infor.getFile_id());
    
    		FileInputStream inputFile = null;
    		String base64 = null;
    
    		try { 
    			inputFile = new FileInputStream(file);
    			byte[] buffer = new byte[(int) file.length()];
    			byte[] bytes = new byte[inputFile.available()];
    			int length = inputFile.read(bytes);
    			base64 = Base64.getEncoder().encodeToString(bytes);
    		} catch (FileNotFoundException e) { 
    			e.printStackTrace();
    		} catch (IOException e) { 
    			e.printStackTrace();
    		} finally { 
    			try { 
    				if (inputFile != null) { 
    					inputFile.close();
    				}
    			} catch (IOException e) { 
    				e.printStackTrace();
    			}
    		}
    		
    		return "data:text/xml;base64,"+base64;
    	}
    	
    	
    }

FileType：

import java.io.ByteArrayInputStream;
    import java.io.File;
    import java.io.FileInputStream;
    import java.io.FileNotFoundException;
    import java.io.FileOutputStream;
    import java.io.IOException;
    import java.io.InputStream;
    import java.io.OutputStream;
    import java.math.BigDecimal;
    import java.text.SimpleDateFormat;
    import java.util.Base64;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import javax.servlet.http.HttpServletRequest;
    import javax.servlet.http.HttpServletResponse;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.beans.factory.annotation.Value;
    import org.springframework.transaction.annotation.Transactional;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RequestMethod;
    import org.springframework.web.bind.annotation.RequestParam;
    import org.springframework.web.bind.annotation.RestController;
    import org.springframework.web.multipart.MultipartFile;
    import org.springframework.web.multipart.MultipartHttpServletRequest;
    import org.springframework.web.util.WebUtils;
    
    @RestController
    @Transactional
    @RequestMapping("/upload")
    public class UploadController { 
    	@Autowired
    	public UploadService service;
    	@Autowired
    	public FileType fileType;
    
    	@Value("${upload.path:{#/opt/data/upload}}")
    	private String basepath;
    
    	@Value("${file.endstr}")
    	private String endstr;
    
    	private IIdentityService ident = AdapterFactory.getIdentityService();
    
    	@RequestMapping(value = "/test", method = RequestMethod.GET)
    	public String test() { 
    		return "1234567890";
    	}
    
    	@RequestMapping(value = "/upload", method = {  RequestMethod.GET, RequestMethod.POST })
    	// @PathVariable("tableName")String tableName,@RequestParam("file")
    	// MultipartFile file
    	public Map<String, Object> upload(HttpServletRequest request) { 
    
    		OutputStream out = null;
    		InputStream is = null;
    		Map<String, Object> result = new HashMap<String, Object>();
    
    		String tableName = request.getParameter("tableName");
    		String id = request.getParameter("pkVal");
    		String name = request.getParameter("colName");
    		String fileTypes = request.getParameter("fileType");
    
    		String contentType = request.getContentType();
    		if (contentType == null || !contentType.toLowerCase().startsWith("multipart/")) { 
    			result.put("code", 500);
    			result.put("msg", "文件不存在或者文件内容为空");
    			return result;
    		}
    
    		MultipartHttpServletRequest multipartRequest = WebUtils.getNativeRequest(request,
    				MultipartHttpServletRequest.class);
    		MultipartFile file = multipartRequest.getFile("file");
    		// 判断文件是否存在
    		if (file.isEmpty()) { 
    			result.put("code", 500);
    			result.put("msg", "文件不存在");
    			return result;
    		}
    		String fileName = file.getOriginalFilename();
    
    		String substring = fileName.substring(fileName.indexOf(".") + 1, fileName.length());
    
    		// 自定义路径
    		SimpleDateFormat fm = new SimpleDateFormat("yyyyMMdd");
    		SimpleDateFormat fm2 = new SimpleDateFormat("yyyyMMddHHmmss");
    		String filePath = File.separator + "upload" + File.separator + fm.format(new Date()) + File.separator
    				+ fm2.format(new Date()) + "." + substring;
    		File dest = new File(basepath + filePath);
    		if (!dest.getParentFile().exists()) { 
    			dest.getParentFile().mkdirs();
    		}
    
    		try { 
    			byte[] bytes = file.getBytes();
    			out = new FileOutputStream(dest);
    			is = new ByteArrayInputStream(bytes);
    			byte[] buff = new byte[1024];
    			int len = 0;
    			while ((len = is.read(buff)) != -1) { 
    				out.write(buff, 0, len);
    			}
    			is.close();
    			out.close();
    			// 验证文件类型
    			fileType.getAllFileType();//加载文件类型
    			String fileType = FileType.getFileType(dest);
    
    			if (checkType(fileType.substring(fileType.indexOf("+") + 1))) { 
    				if (dest.delete()) { 
    					result.put("msg2", "文件删除成功");
    				}
    				;
    				result.put("code", 500);
    				result.put("msg", "文件类型不符");
    				return result;
    			}
    
    			// 保存上传信息
    			UploadFileInformation infor = new UploadFileInformation();
    			infor.setMain_table(tableName);// 主记录表名
    			infor.setMain_id(id);// 主记录id
    
    			infor.setFile_name(fileName);// 文件名称
    			infor.setFile_id(filePath);// 文件标识路径
    			infor.setSmall_id(filePath);// 缩略图标识路径
    			infor.setMain_field(name);// 主记录字段名称
    
    			infor.setFile_type(fileTypes == null ? "图片" : fileTypes);// 文件类型
    			infor.setReg_date(new Date());// 登记时间
    
    			double size = file.getSize();
    			double kilobytes = (size / 1024);
    			double megabytes = (kilobytes / 1024);
    			infor.setAtt_size(new BigDecimal(String.format("%.2f", megabytes)));// 文件大小
    
    			// 人员信息 TODO
    			String reg_staff_id = null;
    			String reg_staff_name = null;
    			String iscUserId = null;
    			if (iscUserId == null) { 
    				iscUserId = (String) request.getAttribute("user_id");
    			}
    			if (null == iscUserId || ("").equals(iscUserId) || iscUserId.equals("null")) { 
    				reg_staff_id = "1";
    				reg_staff_name = "2";
    			} else { 
    				String userinfo[] = iscUserId.split(":");
    				List<User> users = ident.getUserByIds(new String[] {  userinfo[0] });
    				reg_staff_name = users.get(0).getName();
    				reg_staff_id = users.get(0).getId();
    			}
    			infor.setReg_staff_id(reg_staff_id);
    			infor.setReg_staff_name(reg_staff_name);
    
    			// infor.setATT_FILE(new Byte("99"));//数据库存储功能的存储字段
    			service.uploadFileInformation(infor);
    
    			result.put("code", 200);
    			result.put("msg", "文件上传成功");
    			return result;
    		} catch (Exception e) { 
    			e.printStackTrace();
    			result.put("code", 500);
    			result.put("msg", "文件上传失败");
    			return result;
    		}
    	}
    
    	private boolean checkType(String substring) { 
    		boolean open = false;
    		
    		if("null".equals(substring)){ 
    			open = true;
    		}
    		return open;
    	}
    
    	@RequestMapping(value = "/download", method = RequestMethod.GET)
    	public Map<String, Object> download(HttpServletRequest request, HttpServletResponse response,
    			@RequestParam("tableName") String tableName, @RequestParam("pkVal") String pkVal,
    			@RequestParam("colName") String colName) { 
    		UploadFileInformation infor = new UploadFileInformation();
    		infor.setMain_table(tableName);
    		infor.setMain_id(pkVal);
    		infor.setMain_field(colName);
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 500);
    		result.put("result", "");
    		result.put("msg", "下载失败");
    		infor = service.findOneByTABLE_NAMEAndPK_VALAndCOL_NAME(infor);
    		if (infor == null) { 
    			return result;
    		}
    		String fileName = infor.getFile_name();
    		result.put("fileName", fileName);
    		File file = new File(basepath + infor.getFile_id());
    
    		FileInputStream inputFile = null;
    		String base64 = null;
    
    		try { 
    			inputFile = new FileInputStream(file);
    			byte[] buffer = new byte[(int) file.length()];
    			byte[] bytes = new byte[inputFile.available()];
    			int length = inputFile.read(bytes);
    			base64 = Base64.getEncoder().encodeToString(bytes);
    			result.put("code", 200);
    			result.put("result", "data:text/xml;base64," + base64);
    			result.put("msg", "");
    			return result;
    		} catch (FileNotFoundException e) { 
    			e.printStackTrace();
    		} catch (IOException e) { 
    			e.printStackTrace();
    		} finally { 
    			try { 
    				if (inputFile != null) { 
    					inputFile.close();
    				}
    			} catch (IOException e) { 
    				e.printStackTrace();
    			}
    		}
    		result.put("msg", "下载失败。。。");
    		return result;
    	}
    
    	@RequestMapping(value = "/show", method = RequestMethod.GET)
    	public Map<String, Object> show(HttpServletRequest request, HttpServletResponse response,
    			@RequestParam("tableName") String tableName, @RequestParam("pkVal") String pkVal,
    			@RequestParam("colName") String colName) { 
    		UploadFileInformation infor = new UploadFileInformation();
    		infor.setMain_table(tableName);
    		infor.setMain_id(pkVal);
    		infor.setMain_field(colName);
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 500);
    		result.put("result", "");
    		result.put("msg", "预览错误");
    		infor = service.findOneByTABLE_NAMEAndPK_VALAndCOL_NAME(infor);
    		if (infor == null) { 
    			return result;
    		}
    		String fileName = infor.getFile_name();
    		File file = new File(basepath + infor.getFile_id());
    
    		FileInputStream inputFile = null;
    		String base64 = null;
    
    		try { 
    			inputFile = new FileInputStream(file);
    			byte[] buffer = new byte[(int) file.length()];
    			byte[] bytes = new byte[inputFile.available()];
    			int length = inputFile.read(bytes);
    			base64 = Base64.getEncoder().encodeToString(bytes);
    			result.put("code", 200);
    			result.put("result", "data:text/xml;base64," + base64);
    			result.put("msg", "");
    			return result;
    		} catch (FileNotFoundException e) { 
    			e.printStackTrace();
    		} catch (IOException e) { 
    			e.printStackTrace();
    		} finally { 
    			try { 
    				if (inputFile != null) { 
    					inputFile.close();
    				}
    			} catch (IOException e) { 
    				e.printStackTrace();
    			}
    		}
    		result.put("msg", "预览错误。。。");
    		return result;
    	}
    
    	/** * 根据id 类型 返回所有信息 * @param mainId id * @param type 文件类型 * @param isReturnFile 是否返回64 1 ：返回 * @return */
    	@RequestMapping(value = "/findbymainidandtype", method = RequestMethod.GET)
    	public Map<String, Object> findbymainidandtype(
    			@RequestParam("mainId") String mainId,
    			@RequestParam("type") String type,
    			@RequestParam("isReturnFile") String isReturnFile
    			) { 
    		List<UploadFileInformation> data = service.findbymainid(mainId,type);
    		
    		if("1".equals(isReturnFile)){ 
    			for (UploadFileInformation uploadFileInformation : data) { 
    				String base64 = toBase64(uploadFileInformation);
    				uploadFileInformation.setImg_base64(base64);
    			}
    		}
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 200);
    		result.put("data", data);
    		result.put("msg", "");
    		return result;
    
    	}
    	/** * 根据 主记录ID 查询所有的信息 * * @param mainId * @return */
    	@RequestMapping(value = "/findbymainid", method = RequestMethod.GET)
    	public Map<String, Object> findbymainid(
    			@RequestParam("mainId") String mainId) { 
    		List<UploadFileInformation> data = service.findbymainid(mainId,null);
    		
    		for (UploadFileInformation uploadFileInformation : data) { 
    			String base64 = toBase64(uploadFileInformation);
    			uploadFileInformation.setImg_base64(base64);
    		}
    
    		Map<String, Object> result = new HashMap<String, Object>();
    		result.put("code", 200);
    		result.put("data", data);
    		result.put("msg", "");
    		return result;
    
    	}
    	
    	private String toBase64 (UploadFileInformation infor){ 
    		File file = new File(basepath + infor.getFile_id());
    
    		FileInputStream inputFile = null;
    		String base64 = null;
    
    		try { 
    			inputFile = new FileInputStream(file);
    			byte[] buffer = new byte[(int) file.length()];
    			byte[] bytes = new byte[inputFile.available()];
    			int length = inputFile.read(bytes);
    			base64 = Base64.getEncoder().encodeToString(bytes);
    		} catch (FileNotFoundException e) { 
    			e.printStackTrace();
    		} catch (IOException e) { 
    			e.printStackTrace();
    		} finally { 
    			try { 
    				if (inputFile != null) { 
    					inputFile.close();
    				}
    			} catch (IOException e) { 
    				e.printStackTrace();
    			}
    		}di
    		
    		return "data:text/xml;base64,"+base64;
    	}
    	
    	
    }

在yml中定义文件的路径：  
![在这里插入图片描述][20200831095629249.png_pic_center]  
在yml中定义文件类型：  
![在这里插入图片描述][20200831095658527.png_pic_center]

## 前端代码： ##

在操作列中加入文件下载，点击下载，调用函数

self.customOperations = [ { 
    					caption : "下载",
    					click : function(item) { 
    						var restClient = new RESTClient();
    						var requestUrl = cube.gatewayURL
    								+ `/upload/download?tableName=${ item.main_Table}&pkVal=${ item.main_Id}&colName=${ item.main_Field}`;
    						restClient.get(requestUrl, function(data) { 
    							if (data.code == 200) { 
    								const blob = data.result;
    								// 自定义js的a标签
    								const a = document.createElement("a");
    								// 将a标签隐藏
    								a.style.display = "none";
    								// 获取下载文件的base64路径
    								a.href = data.result;
    								// 文件名
    								a.download = data.fileName;
    								// 将a标签增加到页面上
    								document.body.appendChild(a);
    								// 点击事件
    								a.click();
    								// 使用完毕移除a标签
    								document.body.removeChild(a);
    							} else { 
    								alert("下载失败");
    							}
    
    						});
    						console.log(item)
    					}
    				} ]

[20200831095629249.png_pic_center]: /images/20221123/466865e172ac41b88556cd42a0343dfd.png
[20200831095658527.png_pic_center]: /images/20221123/7ebdf2d31f6548dd84173dda53c5a5fb.png