通过图片url获取图片数据

import java.io.ByteArrayOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;



public static byte[] image2Byte(String imgUrl) {
        URL url = null;
        InputStream is = null;
        ByteArrayOutputStream outStream = null;
        HttpURLConnection httpUrl = null;
        try{
            url = new URL(imgUrl);
            httpUrl = (HttpURLConnection) url.openConnection();
            httpUrl.connect();
            is = httpUrl.getInputStream();
            outStream = new ByteArrayOutputStream();
            //创建一个Buffer字符串
            byte[] buffer = new byte[1024];
            //每次读取的字符串长度，如果为-1，代表全部读取完毕
            int len = 0;
            //使用一个输入流从buffer里把数据读取出来
            while( (len=is.read(buffer)) != -1 ){
                //用输出流往buffer里写入数据，中间参数代表从哪个位置开始读，len代表读取的长度
                outStream.write(buffer, 0, len);
            }
            // 对字节数组Base64编码
            return outStream.toByteArray();
        }catch (Exception e) {
            e.printStackTrace();
        }
        finally{
            if(is != null)
            {
                try {
                    is.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(outStream != null)
            {
                try {
                    outStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }
            }
            if(httpUrl != null)
            {
                httpUrl.disconnect();
            }
        }
        return null;
    }