如何从网络中获取png图片
1. J2ME// 方法1Connector conn = Connector.open(url, Connector.READ_WRITE, true);InputStream is = ((HttpConnection) conn).openInputStream();Image img = Image.createImage(is);// 方法2ByteArrayOutputStream baos = new ByteArrayOutputStream();byte[] bytes = new byte;int size = 0, totalSize = 0;HttpConnection conn = (HttpConnection) Connector.open(url, Connector.READ_WRITE, true);InputStream is = conn.openInputStream();try {while ((size = is.read(bytes)) != -1) {baos.write(bytes, 0, size);totalSize += size;}} catch (IOException e) {System.out.println("IOEx = " + e.toString());}Image img = Image.createImage(baos.toByteArray(), 0, totalSize);bytes = null; 2. Android
// 方法1public class MapAppl extends Activity {protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(new mapView(this));}private class mapView extends View {public mapView(Context context) {super(context);}protected void onDraw(Canvas canvas) {super.onDraw(canvas);Bitmap bm = null;try {InputStream is = getInputStream("http://www.tiexin.com/images/map_blocks/1/4/3/3/00000037_00000031.png");bm = BitmapFactory.decodeStream(is);if (is != null) {is.close();is = null;}} catch (IOException e) {e.printStackTrace();}Paint p = new Paint();canvas.drawBitmap(bm, 40, 40, p);}private InputStream getInputStream(String strURL) throws IOException {URL url = new URL(strURL);HttpURLConnection conn = (HttpURLConnection) url.openConnection();conn.setDoInput(true);conn.setConnectTimeout(1000);conn.setRequestMethod("GET");conn.connect();for (int i = 0; i < 5; i++) { // 连接5次if (conn.getResponseCode() == HttpURLConnection.HTTP_OK) {InputStream is = conn.getInputStream();if (conn != null) {//conn.disconnect(); // 在未对is进行处理前，不能conn.disconnect()conn = null;}return is;}}return null;}}}
// 方法2public class MapAppl2 extends Activity {protected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(new mapView(this));}private class mapView extends View {public mapView(Context context) {super(context);}protected void onDraw(Canvas canvas) {super.onDraw(canvas);Bitmap bm = null;try {bm = getImage("http://www.tiexin.com/images/map_blocks/1/4/3/3/00000037_00000033.png");} catch (IOException e) {e.printStackTrace();}Paint p = new Paint();canvas.drawBitmap(bm, 40, 40, p);}public final Bitmap getImage(String strUrl) throws IOException {Bitmap bm;HttpClient httpclient = new DefaultHttpClient();HttpGet httpget = new HttpGet(strUrl);HttpResponse response = httpclient.execute(httpget);HttpEntity entity = response.getEntity();if (entity != null) {InputStream input= entity.getContent();byte[] bitImage = new byte, data=new byte;int totalSize = 0, size = 0;while ((size = input.read(data)) != -1) {System.arraycopy(data, 0, bitImage, totalSize, size);totalSize += size;}bm = totalSize > 0 ? BitmapFactory.decodeByteArray(bitImage, 0, totalSize) : null;} else {bm = null;}// Do not feel like reading the response body// Call abort on the request objecthttpget.abort();return bm;}}}一般建议使用HttpClient进行连接，因为在redirect的时候URL不管用。此外，Http连接后，一定要判断返回的statusCode(ResponseCode)。
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