java 读取图片，兼容本地图片路径与http文件

版权声明：本文为博主原创文章，未经博主允许不得转载。 https://blog.csdn.net/wangbailin2009/article/details/50371865

java直接使用流读取远程图片会有失真的现象，稍作修改。

public static byte[] readImg(String urlOrPath){

        Logger logger = Logger.getLogger(FileUtils.class);
        byte[] imgBytes = new byte[1024 * 1024];

        ByteArrayOutputStream out = new ByteArrayOutputStream();
        BufferedInputStream reader = null;
        InputStream in = null;
        URLConnection conn = null;
        File temFile = null;

        try {
            if(!urlOrPath.startsWith("http:")){
                File imgFile = new File(urlOrPath);
                if(!imgFile.isFile() || !imgFile.exists() || !imgFile.canRead()){
                    logger.info("图片不存在或不可读");
                    return new byte[0];
                }
                in = new FileInputStream(imgFile);
            }else{
                URL imgUrl = new URL(urlOrPath);
                conn = imgUrl.openConnection();
                temFile = new File(new Date().getTime() + ".jpg");
                FileOutputStream tem = new FileOutputStream(temFile);
                BufferedImage image = ImageIO.read(conn.getInputStream());
                ImageIO.write(image, "jpg", tem);
                in = new FileInputStream(temFile);
            }
            reader = new BufferedInputStream(in);
            byte[] buffer = new byte[1024];
            while(reader.read(buffer) != -1){
                out.write(buffer);
            }
            imgBytes = out.toByteArray();

        } catch (Exception e) {
            logger.error("读取图片发生异常", e);
        }finally{
            if(reader != null){
                try {
                    reader.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            if(in != null){
                try {
                    in.close();
                } catch (IOException e) {
                    // TODO Auto-generated catch block
                    e.printStackTrace();
                }
            }
            try {
                out.close();
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            if(temFile != null){
                temFile.delete();
            }
        }
        return imgBytes;
    }