Java创建临时文件写入数据并读取成byte数组

悠悠 2022-11-21 14:51 199阅读 0赞

需求过程： 在内存中把文件地址写入到txt中，并以byte数组存入到oss里面

### 1.准备数据 ###

// 准备数据
    List < String > fileList = new ArrayList < > ();
    if(StringUtils.isNotBlank(fileUrls))
    { 
        String[] split = fileUrls.split(",");
        for(String s: split)
        { 
            fileList.add(s);
        }
    }
    // 转成json
    String fileListJsonString = JSONArray.toJSONString(fileList);
    // 存入到txt里面
    byte[] bytes = HttpClientUtil.craeteTempFileTxt(fileListJsonString);

### 2.创建临时文件 ###

#### 2.1 扩展方法 ####

/** * 创建临时文本文件 * @param txt 内容 * @return * @throws IOException */
    	public static byte[] craeteTempFileTxt(String txt) throws IOException { 
    		File temp = File.createTempFile("data_", ".txt");
    		temp.deleteOnExit();
    		BufferedWriter out = new BufferedWriter(new FileWriter(temp));
    		String jsonString = JSONArray.toJSONString(txt);
    		out.write(jsonString);
    		out.close();
    		if(temp.exists()){ 
    			System.out.println("文件存在");
    			String name = temp.getName();
    			String absolutePath = temp.getAbsolutePath();
    			System.out.println("文件名称:"+name);
    			System.out.println("文件路径"+absolutePath);
    			byte[] bytes = FileUtils.readFileToByteArray(temp);
    			System.out.println(bytes.toString());
    			return bytes;
    		}else{ 
    			System.out.println("文件不存在");
    			return new byte[0];
    		}
    	}
    
    
    	/** * 创建临时文本文件 * @param txt 内容 * @return * @throws IOException */
    	public static byte[] craeteTempFileTxt(String fileName,String txt) throws IOException { 
    		File temp = File.createTempFile(fileName, ".txt");
    		temp.deleteOnExit();
    		BufferedWriter out = new BufferedWriter(new FileWriter(temp));
    		String jsonString = JSONArray.toJSONString(txt);
    		out.write(jsonString);
    		out.close();
    		if(temp.exists()){ 
    			System.out.println("文件存在");
    			String name = temp.getName();
    			String absolutePath = temp.getAbsolutePath();
    			System.out.println("文件名称:"+name);
    			System.out.println("文件路径"+absolutePath);
    			byte[] bytes = FileUtils.readFileToByteArray(temp);
    			System.out.println(bytes.toString());
    			return bytes;
    		}else{ 
    			System.out.println("文件不存在");
    			return new byte[0];
    		}
    	}
    
    
    	/** * 创建临时文本文件 * @param txt 内容 * @return * @throws IOException */
    	public static Map<String,Object> craeteTempFileTxtDetail(String txt) throws IOException { 
    		Map<String,Object> resultMap = new HashMap<>();
    		File temp = File.createTempFile("data_", ".txt");
    		temp.deleteOnExit();
    		BufferedWriter out = new BufferedWriter(new FileWriter(temp));
    		String jsonString = JSONArray.toJSONString(txt);
    		out.write(jsonString);
    		out.close();
    		if(temp.exists()){ 
    			System.out.println("文件存在");
    			String name = temp.getName();
    			String absolutePath = temp.getAbsolutePath();
    			System.out.println("文件名称:"+name);
    			System.out.println("文件路径"+absolutePath);
    			byte[] bytes = FileUtils.readFileToByteArray(temp);
    			System.out.println(bytes.toString());
    			resultMap.put("fileName",name);
    			resultMap.put("fileTempPath",absolutePath);
    			resultMap.put("fileType","text/plain");
    			resultMap.put("fileBytes",bytes);
    			resultMap.put("file",temp);
    			return resultMap;
    		}else{ 
    			System.out.println("文件不存在");
    			return resultMap;
    		}
    	}
    
    	/** * 创建临时文本文件 * @param txt 内容 * @return * @throws IOException */
    	public static Map<String,Object> craeteTempFileTxtDetail(String fileName,String txt) throws IOException { 
    		Map<String,Object> resultMap = new HashMap<>();
    		File temp = File.createTempFile("data_", ".txt");
    		temp.deleteOnExit();
    		BufferedWriter out = new BufferedWriter(new FileWriter(temp));
    		String jsonString = JSONArray.toJSONString(txt);
    		out.write(jsonString);
    		out.close();
    		if(temp.exists()){ 
    			System.out.println("文件存在");
    			String name = temp.getName();
    			String absolutePath = temp.getAbsolutePath();
    			System.out.println("文件名称:"+name);
    			System.out.println("文件路径"+absolutePath);
    			byte[] bytes = FileUtils.readFileToByteArray(temp);
    			System.out.println(bytes.toString());
    			resultMap.put("fileName",name);
    			resultMap.put("fileTempPath",absolutePath);
    			resultMap.put("fileType","text/plain");
    			resultMap.put("fileBytes",bytes);
    			resultMap.put("file",temp);
    			return resultMap;
    		}else{ 
    			System.out.println("文件不存在");
    			return resultMap;
    		}
    	}

### 3.获取到byte数组 ###

if(bytes.length != 0){ 
                logger.info("外有效的byte数组");
               // do something...
      }else{ 
                logger.error("无效的byte数组");
              // do something...
      }