byte数组和文件之间的相互转换,string转文件流输出

以你之姓@ 2022-05-19 11:51 386阅读 0赞

/**
     * 根据byte数组，生成文件
     * @param bfile 文件数组
     * @param filePath 文件存放路径
     * @param fileName 文件名称
     */
    public static void byte2File(byte[] byte,String filePath,String fileName){
        BufferedOutputStream bos=null;
        FileOutputStream fos=null;
        File file=null;
        try{
            File dir=new File(filePath);
            if(!dir.exists() && !dir.isDirectory()){//判断文件目录是否存在
                dir.mkdirs();
            }
            file=new File(filePath+fileName);
            fos=new FileOutputStream(file);
            bos=new BufferedOutputStream(fos);
            bos.write(byte);
        }
        catch(Exception e){
            System.out.println(e.getMessage());
            e.printStackTrace();
        }
        finally{
            try{
                if(bos != null){
                    bos.close();
                }
                if(fos != null){
                    fos.close();
                }
            }
            catch(Exception e){
                System.out.println(e.getMessage());
                e.printStackTrace();
            }
        }
    }
    /**
     * 获得指定文件的byte数组
     * @param filePath 文件绝对路径
     * @return
     */
    public static byte[] file2Byte(String filePath){
        ByteArrayOutputStream bos=null;
        BufferedInputStream in=null;
        try{
            File file=new File(filePath);
            if(!file.exists()){
                throw new FileNotFoundException("file not exists");
            }
            bos=new ByteArrayOutputStream((int)file.length());
            in=new BufferedInputStream(new FileInputStream(file));
            int buf_size=1024;
            byte[] buffer=new byte[buf_size];
            int len=0;
            while(-1 != (len=in.read(buffer,0,buf_size))){
                bos.write(buffer,0,len);
            }
            return bos.toByteArray();
        }
        catch(Exception e){
            System.out.println(e.getMessage());
            e.printStackTrace();
            return null;
        }
        finally{
            try{
                if(in!=null){
                    in.close();
                }
                if(bos!=null){
                    bos.close();
                }
            }
            catch(Exception e){
                System.out.println(e.getMessage());
                e.printStackTrace();
            }
        }
    }

//字符串转换成数组
    public static byte[] toByteArray(String hexString) {
        hexString = hexString.toLowerCase();
        final byte[] byteArray = new byte[hexString.length() / 2];
        int k = 0;
        for (int i = 0; i < byteArray.length; i++) {// 因为是16进制，最多只会占用4位，转换成字节需要两个16进制的字符，高位在先
            byte high = (byte) (Character.digit(hexString.charAt(k), 16) & 0xff);
            byte low = (byte) (Character.digit(hexString.charAt(k + 1), 16) & 0xff);
            byteArray[i] = (byte) (high << 4 | low);
            k += 2;
        }
        return byteArray;
    }

/**
     * 字符串转换成字节流并输出
     * 
     */
    public void file(HttpServletResponse response,String xx){
    
        byte[] bytes = CommonUtil.toByteArray(xx);
        OutputStream os = null;
        try {
            os = response.getOutputStream();
            response.addHeader("Content-Type", "image/jpeg");
            os.write(bytes);
            os.flush();
        }catch (Exception e){
            e.printStackTrace();
        }finally {
            if (os != null) {
                try {
                    os.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
        }
    }