【android初级】之Android之从网络上获取数据（图片，网页，xml,json等）

1>从网络上获取数据（图片，网页，xml,json等）



A.从网络上获取一张图片，然后显示到手机上

这是在java中

public class ImageRequest {

/**

* @param args

*/

public static void main(String[] args) throws Exception {

URL url = new URL("http://i3.itc.cn/20100707/76c_0969b700_d5b4_41cd_8243_9b486be92cc4_0.jpg");

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[] data = readInputStream(inStream);//得到图片的二进制数据

File imageFile = new File("itcast.jpg");//保存在项目下

FileOutputStream outStream = new FileOutputStream(imageFile);

outStream.write(data);

outStream.close();

}

public static byte[] readInputStream(InputStream inStream) throws Exception{

ByteArrayOutputStream outStream = new ByteArrayOutputStream();

byte[] buffer = new byte[1024];//定义一个1k的缓冲区

int len = 0;

while( (len=inStream.read(buffer)) != -1 ){//返回的是实际的字节数

outStream.write(buffer, 0, len);//将缓冲区的数据写入到内存中

}

inStream.close();

return outStream.toByteArray();

}

}

在手机上

button.setOnClickListener(new View.OnClickListener() {

@Override

public void onClick(View v) {

String path = pathText.getText().toString();

try {

byte[] data = ImageService.getImage(path);

Bitmap bitmap = BitmapFactory.decodeByteArray(data, 0, data.length);//生成位图

imageView.setImageBitmap(bitmap);//显示图片

} catch (Exception e) {

Toast.makeText(ImageShowActivity.this, R.string.error, 1).show();

Log.e(TAG, e.toString());

}

}});

<!-- 访问网络的权限 -->

<uses-permission android:name="android.permission.INTERNET"/>

public class StreamTool {

/**

* 从输入流中获取数据

* @param inStream 输入流

* @return

* @throws Exception

*/

public static byte[] readInputStream(InputStream inStream) throws Exception{

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();

}

}

-----------------------------------------------------------------------------------------------------

public class ImageService {



public static byte[] getImage(String path) throws Exception {

URL url = new URL("http://i3.itc.cn/20100707/76c_0969b700_d5b4_41cd_8243_9b486be92cc4_0.jpg");

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

return StreamTool.readInputStream(inStream);//得到图片的二进制数据

}

}

B.从网络上获取网页(用的比较少)

byte[] data = readInputStream(inStream);//得到网页的二进制数据

String html = new String(data,"gb2312");

C.从网络上获取xml数据，然后显示在手机上

android手机模拟器本身绑定在模拟器上，所以访问web service的时候不能用local host

或者用127.0.0.1。而应该使用局域网上的ip地址。

public class VideoService {

/**

* 获取最新的视频资讯

* @return

* @throws Exception

*/

public static List<Video> getLastVideos() throws Exception{

String path = "http://192.168.1.100:8080/videoweb/video/list.do";

URL url = new URL(path);

HttpURLConnection conn = (HttpURLConnection)url.openConnection();

conn.setReadTimeout(5*1000);

conn.setRequestMethod("GET");

InputStream inStream = conn.getInputStream();

return parseXML(inStream);

}

/**

* 解析服务器返回的协议，得到视频资讯

* @param inStream

* @return

* @throws Exception

*/

private static List<Video> parseXML(InputStream inStream) throws Exception{

List<Video> videos = null;

Video video = null;

XmlPullParser parser = Xml.newPullParser();

parser.setInput(inStream, "UTF-8");

int eventType = parser.getEventType();//产生第一个事件

while(eventType!=XmlPullParser.END_DOCUMENT){//只要不是文档结束事件

switch (eventType) {

case XmlPullParser.START_DOCUMENT:

videos = new ArrayList<Video>();

break;



case XmlPullParser.START_TAG:

String name = parser.getName();//获取解析器当前指向的元素的名称

if("video".equals(name)){

video = new Video();

video.setId(new Integer(parser.getAttributeValue(0)));

}

if(video!=null){

if("title".equals(name)){

video.setTitle(parser.nextText());//获取解析器当前指向元素的下一个文本节点的值

}

if("timelength".equals(name)){

video.setTime(new Integer(parser.nextText()));

}

}

break;



case XmlPullParser.END_TAG:

if("video".equals(parser.getName())){

videos.add(video);

video = null;

}

break;

}

eventType = parser.next();

}

return videos;

}

}

D.从网络上获取json数据，然后显示在手机上

public class VideoService {

/**

* 获取最新的视频资讯

* @return

* @throws Exception

*/



public static List<Video> getJSONLastVideos() throws Exception{

List<Video> videos = new ArrayList<Video>();

String path = "http://192.168.1.100:8080/videoweb/video/list.do?format=json";

URL url = new URL(path);

HttpURLConnection conn = (HttpURLConnection)url.openConnection();

conn.setReadTimeout(5*1000);

conn.setRequestMethod("GET");

InputStream inStream = conn.getInputStream();

byte[] data = StreamTool.readInputStream(inStream);

String json = new String(data);

JSONArray array = new JSONArray(json);

for(int i=0 ; i < array.length() ; i++){

JSONObject item = array.getJSONObject(i);

int id = item.getInt("id");

String title = item.getString("title");

int timelength = item.getInt("timelength");

videos.add(new Video(id, title, timelength));

}

return videos;

}



}