从远程路径读取图片，进行base64转码

public static byte[] getImageFromNetByUrl(String strUrl){  
        try {  
            URL url = new URL(strUrl);  
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();  
            conn.setRequestMethod("GET");  
            conn.setConnectTimeout(5 * 1000);  
            InputStream inStream = conn.getInputStream();//通过输入流获取图片数据  
            byte[] btImg = readInputStream(inStream);//得到图片的二进制数据  
            return btImg;  
        } catch (Exception e) {  
            e.printStackTrace();  
        }  
        return null;  
    }  
　　　　//由于读取需要一定时间，所以不能单纯往字节数组里读，所以需要判断是否读完
	public static byte[] readInputStream(InputStream inStream) throws Exception{  
　　//存放读取的所有的字节数组
        ByteArrayOutputStream outStream = new ByteArrayOutputStream();  
        byte[] buffer = new byte[1024];  
        int len = 0;  
        while( (len=inStream.read(buffer)) != -1 ){  
            outStream.write(buffer, 0, len);  
        }  
        inStream.close();  
        return outStream.toByteArray();  
    }  
private static String getImageStr(String imgUrl) {
        byte[] data = null;
        try {
            data =getImageFromNetByUrl(imgUrl);;
        } catch (Exception e) {
            e.printStackTrace();
        }
        BASE64Encoder encoder = new BASE64Encoder();
        return encoder.encode(data);
    }