用url从网络上下载一张图片（二进制），转换成BitMap格式的图片

//==========================用了两种方法======================
1.------------用流方式
try {
            //实例化url
            URL url = new URL(imgurl);
            //载入图片到输入流
            java.io.BufferedInputStream bis = new BufferedInputStream(url.openStream());
            //实例化存储字节数组
            byte[] bytes = new byte[100];
            //设置写入路径以及图片名称
            OutputStream bos = new FileOutputStream(new File( "C:\\thetempimg.gif"));
            int len;
            while ((len = bis.read(bytes)) > 0) {
                bos.write(bytes, 0, len);
            }
            bis.close();
            bos.flush();
            bos.close();
            //关闭输出流
            b=true;
        } catch (Exception e) {
            //如果图片未找到
            b=false;
        }

int[] a = new int[2];
        if(b){    //图片存在
            //得到文件
            java.io.File file = new java.io.File("C:\\thetempimg.gif");
            BufferedImage bi = null;
            try {
                //读取图片
                bi = javax.imageio.ImageIO.read(file);
            } catch (IOException ex) {
                ex.printStackTrace();
            }
            a[0] = bi.getWidth(); //获得 宽度
            a[1] = bi.getHeight(); //获得 高度
            //删除文件
            file.delete();
        }else{     //图片不存在
            a=null;
        }
       return a;

    }





// 显示网络上的图片
public static Bitmap returnBitMap(String url) {
Log.i("returnBitMap","url="+url);
URL myFileUrl = null;
Bitmap bitmap = null;
try {
myFileUrl = new URL(url);
} catch (MalformedURLException e) {
e.printStackTrace();
}
try {
HttpURLConnection conn = (HttpURLConnection) myFileUrl
.openConnection();
conn.setDoInput(true);
conn.connect();
InputStream is = conn.getInputStream();
bitmap = BitmapFactory.decodeStream(is);
is.close();
} catch (IOException e) {
e.printStackTrace();
}
return bitmap;
}