HttpURLConnection下载图片的两种方式

public class MainActivity extends AppCompatActivity {

private ImageView iv;

private String imageurl = "http://img06.tooopen.com/images/20161106/tooopen_sl_185050524199.jpg";    private Bitmap bitmap;

@Override    protected void onCreate(Bundle savedInstanceState) {        super.onCreate(savedInstanceState);        setContentView(R.layout.activity_main);

iv = (ImageView) findViewById(R.id.iv_show);

findViewById(R.id.load).setOnClickListener(new View.OnClickListener() {            @Override            public void onClick(View view) {                new Thread(loadrunable).start();            }        });    }

private Runnable loadrunable = new Runnable() {

private InputStream is;

@Override        public void run() {

try {             URL imgUrl = new URL(imageurl);            // 使用HttpURLConnection打开连接            HttpURLConnection urlConn = (HttpURLConnection) imgUrl                    .openConnection();            urlConn.setDoInput(true);                urlConn.setDoOutput(false);                urlConn.setRequestMethod("GET");                urlConn.setConnectTimeout(3000);                urlConn.setUseCaches(true);            urlConn.connect();                int code = urlConn.getResponseCode();                Log.e("tag", "run: "+code );                // 将得到的数据转化成InputStream            InputStream is = urlConn.getInputStream();            // 将InputStream转换成Bitmap//            bitmap = getBitmapInputStream(is);

byte[] bytesInputStream = getBytesInputStream(is);                bitmap = BitmapFactory.decodeByteArray(bytesInputStream,0,bytesInputStream.length);

Message msgone = new Message();                   msgone.what = 1;                    handler.sendMessage(msgone);

} catch (MalformedURLException e) {                e.printStackTrace();            } catch (IOException e) {                e.printStackTrace();            }finally {

if (null != is){                    try {                        is.close();                    } catch (IOException e) {                        e.printStackTrace();                    }                }            }        }    };

private Handler handler = new Handler(){        @Override        public void handleMessage(Message msg) {//            super.handleMessage(msg);            Log.e("tag", "handleMessage: "+msg.what );

if (null != bitmap && null != iv){                iv.setImageBitmap(bitmap);            }        }    };

public Bitmap getBitmapInputStream(InputStream is){        Bitmap bp;        bp = BitmapFactory.decodeStream(is);

return bp;    }

public byte[] getBytesInputStream( InputStream is) throws IOException {

ByteArrayOutputStream arrayOutputStream = new ByteArrayOutputStream();        byte[] buff = new byte[512];        int len;        while ((len = is.read(buff))!= -1){

arrayOutputStream.write(buff,0,len);        }

is.close();        arrayOutputStream.close();

return arrayOutputStream.toByteArray();

}}

重点：不要设置setDoOutput(true)，post请求上传参数得设置为true;它默认为false:  urlConn.setDoOutput(false);

参考博客：  http://blog.csdn.net/ameyume/article/details/6528205