android 从服务器下载图片，并保存到本地

例子：

    从服务器获取图片路径，从中取得其中的两条数据，进行下载。

先创建一个实体类，保存图片的数据：

public class PictureSet {
    public int cameraId;
    public String pictureName;
    public String pictureData;
    public String createTime;

    public PictureSet(int cameraId1,String pictureName1,String pictureData1,String createTime1){
        this.cameraId = cameraId1;
        this.pictureName = pictureName1;
        this.pictureData = pictureData1;
        this.createTime = createTime1;
    }
    public PictureSet(){

    }
}

页面：

public class ImgDownActivity extends Activity implements View.OnClickListener {
    private TextView tv_path1,tv_path2;
    private Button btn_obtain,btn_downImg1,btn_downImg2;
    private ImageView iv_img1,iv_img2;
    private String netImgStr;
    private String retCode,retInfo;
    private Bitmap bm1,bm2;
    private ProgressDialog mDialog;
    private String passMsg1,passMsg2;
    //下载路径
    private final static String reqeustURL  = "http://103.8.220.166:40000/lechu/device/image/filedownload";

    //保存路径
    private final static String ALBUM_PATH = Environment.getExternalStorageDirectory()+"/download_test/";


    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_fild_down_load);
        //获取网络图片信息
        btn_obtain = (Button)findViewById(R.id.btn_obtain);
        btn_obtain.setOnClickListener(this);

        tv_path1 = (TextView)findViewById(R.id.tv_imgPath1);
        tv_path2 = (TextView)findViewById(R.id.tv_imgPath2);
        iv_img1 = (ImageView)findViewById(R.id.iv_img1);
        iv_img2 = (ImageView)findViewById(R.id.iv_img2);
        btn_downImg1 = (Button)findViewById(R.id.btn_down1);
        btn_downImg2 = (Button)findViewById(R.id.btn_down2);
        btn_downImg1.setOnClickListener(this);
        btn_downImg2.setOnClickListener(this);

    }

    @Override
    public void onClick(View v) {
        switch (v.getId()){
            case R.id.btn_obtain:
                final ObtainHandler obtainHandler = new ObtainHandler();
                new Thread(){
                    public void run(){
                        Looper.prepare();
                        ImgDownUtil imgDownUtil = new ImgDownUtil();
                        //netImgStr = getImgFromServer(getLocalMac());
                        netImgStr = imgDownUtil.getImgFromServer(getLocalMac());
                        Log.i("inputstream",netImgStr);
                        //Bundle mBundle = getBundleFromStr(netImgStr);
                        Bundle mBundle = imgDownUtil.getBundleFromStr(netImgStr);

                        //获取图片信息，并将其转换成byte[]
                        List imgList = (ArrayList)(mBundle.getStringArrayList("retResult"));
                        byte[] data = null;
                        List<byte[]> byteList = new ArrayList<byte[]>();
                        for(int j=0;jpictureData);
                            byteList.add(data);
                            mBundle.putByteArray("imgPath" + j, data);
                        }

                        Message msg = new Message();
                        msg.setData(mBundle);
                        obtainHandler.sendMessage(msg);
                    }
                }.start();
                break;
            case R.id.btn_down1:
                mDialog = ProgressDialog.show(ImgDownActivity.this,"保存图片","图片正在保存，请稍候……",true);
                final SaveImgHandler saveImgHandler = new SaveImgHandler();
                new Thread(){
                    public void run(){
                        Looper.prepare();
                        ImgDownUtil imgDownUtil = new ImgDownUtil();
                        try{
                            imgDownUtil.saveFile(bm1, "bm1.jpg");
                            passMsg1 = "图片保存成功！";
                        }catch (Exception ex){
                            ex.printStackTrace();
                            passMsg1 = "图片保存失败！";
                        }
                        saveImgHandler.sendMessage(saveImgHandler.obtainMessage());
                    }
                }.start();
                break;
            case R.id.btn_down2:
                mDialog = ProgressDialog.show(ImgDownActivity.this,"图片保存","图片正在保存，请稍候……",true);
                final SaveImgHandler saveImgHandler1 = new SaveImgHandler();
                new Thread(){
                    public void run(){
                        Looper.prepare();
                        try{
                            ImgDownUtil imgDownUtil = new ImgDownUtil();
                            imgDownUtil.saveFile(bm2,"bm2.jpg");
                            passMsg1 = "图片保存成功！";
                        }catch (Exception ex){
                            ex.printStackTrace();
                            passMsg1 = "图片保存失败！";
                        }
                        saveImgHandler1.sendMessage(saveImgHandler1.obtainMessage());
                    }
                }.start();
                break;
        }
    }

    //获取图片信息，并显示在页面上
    class ObtainHandler extends Handler{
        public ObtainHandler(){

        }
        public ObtainHandler(Looper l){
            super(l);
        }
        //更新UI
        public void handleMessage(Message msg){
            Bundle bakBundle = msg.getData();
            retCode = bakBundle.getString("retCode");
            List list = (ArrayList)(bakBundle.getStringArrayList("retResult"));

            if(retCode.equals("00000")){
                Toast.makeText(ImgDownActivity.this,bakBundle.getString("retInfo"),Toast.LENGTH_SHORT).show();
                //显示网络图片的路径
                tv_path1.setText(list.get(0).pictureData);
                tv_path2.setText(list.get(1).pictureData);
                //显示图片
                byte[] imgByte1 = bakBundle.getByteArray("imgPath1");
                bm1 = BitmapFactory.decodeByteArray(imgByte1,0,imgByte1.length);
                Log.i("bm1Info",bm1.getConfig().toString());
                iv_img1.setImageBitmap(bm1);
                byte[] imgByte2 = bakBundle.getByteArray("imgPath2");
                bm2 = BitmapFactory.decodeByteArray(imgByte2,0,imgByte2.length);
                iv_img2.setImageBitmap(bm2);
            }
        }
    }

    //图片保存成功后关闭等待对话框，并弹出页面提示
    class SaveImgHandler extends Handler{
        public SaveImgHandler(){
        }
        public SaveImgHandler(Looper l){
            super(l);
        }
        public void handleMessage(Message msg){
            mDialog.dismiss();
            Toast.makeText(ImgDownActivity.this,passMsg1,Toast.LENGTH_SHORT).show();
        }
    }

    //获取设备的MAC地址
    public String getLocalMac(){
        WifiManager wifiManager = (WifiManager)getSystemService(WIFI_SERVICE);
        WifiInfo info = wifiManager.getConnectionInfo();
        String macStr = info.getMacAddress();
        //将MAC地址转换成小写不带:的形式
        String[] macAddr = macStr.toLowerCase().split(":");
        String mac1="";
        for(int i=0;ilength;i++){
            mac1 = mac1+macAddr[i];
        }
        return mac1;
    }
}

页面布局：

<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
    xmlns:tools="http://schemas.android.com/tools" android:layout_width="match_parent"
    android:layout_height="match_parent" android:paddingLeft="@dimen/activity_horizontal_margin"
    android:paddingRight="@dimen/activity_horizontal_margin"
    android:paddingTop="@dimen/activity_vertical_margin"
    android:paddingBottom="@dimen/activity_vertical_margin"
    android:orientation="vertical">

    <LinearLayout
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <TextView
                android:text="图片1："
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
            <TextView
                android:id="@+id/tv_imgPath1"
                android:layout_width="200dp"
                android:layout_height="wrap_content" />

            <Button
                android:id="@+id/btn_down1"
                android:text="下载"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        LinearLayout>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <ImageView
                android:id="@+id/iv_img1"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
        LinearLayout>
    LinearLayout>
    <LinearLayout
        android:id="@+id/ll_img2"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <TextView
                android:text="图片2："
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
            <TextView
                android:id="@+id/tv_imgPath2"
                android:layout_width="200dp"
                android:layout_height="wrap_content" />
            <Button
                android:id="@+id/btn_down2"
                android:text="下载"
                android:layout_width="match_parent"
                android:layout_height="wrap_content" />
        LinearLayout>
        <LinearLayout
            android:layout_width="wrap_content"
            android:layout_height="wrap_content">
            <ImageView
                android:id="@+id/iv_img2"
                android:layout_width="wrap_content"
                android:layout_height="wrap_content" />
        LinearLayout>
    LinearLayout>
    <LinearLayout
        android:layout_width="match_parent"
        android:layout_height="wrap_content"
        android:orientation="vertical">
        <Button
            android:id="@+id/btn_obtain"
            android:text="获取图片信息"
            android:layout_width="match_parent"
            android:layout_height="wrap_content" />

    LinearLayout>


LinearLayout>

从服务器获取数据，在页面上显示图片，并保存到本地的方法：

public class ImgDownUtil {
    private final static String reqeustURL  = "http://103.8.220.166:40000/lechu/device/image/filedownload";
    private final static String ALBUM_PATH = Environment.getExternalStorageDirectory()+"/download_test/";
    private Bundle bundle;

    public ImgDownUtil(){

    }

    //从服务器上获取响应数据
    public String getImgFromServer(String mac){
        HttpClient client = new DefaultHttpClient();
        HttpGet httpGet = new HttpGet(reqeustURL+"/"+mac+"/");
        String imgStream = null;
        try{
            HttpResponse hresponse = client.execute(httpGet);
            HttpEntity entity = hresponse.getEntity();
            imgStream = EntityUtils.toString(entity);
//            is = entity.getContent();
        }catch (Exception ex){
            ex.printStackTrace();
        }
        return imgStream;
    }

    //将从服务器上获取的字符串转化成Bundle
    public Bundle getBundleFromStr(String str){
        try{
            JSONObject jsonObject = new JSONObject(str);
            bundle = new Bundle();
            bundle.putString("retCode",jsonObject.getString("retCode").toString());
            bundle.putString("retInfo",jsonObject.getString("retInfo").toString());
            //JSONObject subObject = new JSONObject(jsonObject.getString("retResult"));
            String jsonStr = jsonObject.getString("retResult");
//            String str = jsonStr.substring(1).replace("]", "");
            JSONArray jsonArr = new JSONArray(jsonStr);

            List psList = new ArrayList();
            for(int i=0;inew JSONObject(jsonArr.get(i).toString());
                PictureSet ps = new PictureSet();
                ps.cameraId = subObject.getInt("cameraId");
                ps.pictureName = subObject.getString("pictureName");
                ps.createTime = subObject.getString("createTime");
                ps.pictureData = subObject.getString("pictureData");
                psList.add(ps);
                Log.i("subObject", jsonArr.get(i).toString());
            }
            bundle.putStringArrayList("retResult", (ArrayList) psList);
        }catch (Exception ex){
            ex.printStackTrace();
        }
        return bundle;
    }

    //获取图片
    public byte[] getImg(String imgPath){
        try{
            URL url = new URL(imgPath);
            HttpURLConnection conn = (HttpURLConnection)url.openConnection();
            conn.setConnectTimeout(5*1000);
            conn.setRequestMethod("GET");
            InputStream is = conn.getInputStream();
            if(conn.getResponseCode() == HttpURLConnection.HTTP_OK){
                return readStream(is);
            }
        }catch (MalformedURLException mue){
            //URL抛出的异常
            mue.printStackTrace();
        }catch (IOException ie){
            //HttpURLConnection抛出的异常。
            ie.printStackTrace();
        }
        return null;
    }
    //将图片流转化为数据
    public static byte[] readStream(InputStream inputStream){
        ByteArrayOutputStream byteArrayOutputStream = new ByteArrayOutputStream();
        byte[] buffer = new byte[1024];
        int len =0;
        try{
            while ((len = inputStream.read(buffer))!=-1){
                byteArrayOutputStream.write(buffer,0,len);
            }
            byteArrayOutputStream.close();
            inputStream.close();
        }catch (Exception ex){
            ex.printStackTrace();
        }
        return byteArrayOutputStream.toByteArray();
    }


    //保存图片到本地
    public void saveFile(Bitmap bm,String imgName){
        File dirFile = new File(ALBUM_PATH);
        if(!dirFile.exists()){
            dirFile.mkdir();
        }

        File myFile = new File(ALBUM_PATH+imgName);
        try{
            BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(myFile));
            bm.compress(Bitmap.CompressFormat.JPEG,80,bos);
            bos.flush();
            bos.close();
        }catch (Exception ex){
            ex.printStackTrace();
        }

    }
}