网络数据请求实践一：android-async-http实现下载和上传

android-async-http，是一个android异步网络数据请求框架，网络处理均基于Android的非UI线程，通过回调方法处理请求结果。本篇简单介绍一下它的用法，分别实现上传和下载文件的功能。

一.android-async-http简介

1. 开源项目android-async-http地址：
   https://github.com/loopj/android-async-http

2. android-async-http核心组件：
   a). AsyncHttpResponseHandler ——这是一个请求返回处理，成功，失败，开始，完成，等自定义的消息的类；
   b). BinaryHttpResponseHandler extends AsyncHttpResponseHandler ——继承AsyncHttpResponseHandler的子类，这是一个字节流返回处理的类， 该类用于处理图片等类；
   c). JsonHttpResponseHandler extends AsyncHttpResponseHandler ——继承AsyncHttpResponseHandler的子类，这是一个json请求返回处理服务器与客户端用json交流时使用的类；
   d). AsyncHttpRequest implements Runnable ——基于线程的子类，用于 异步请求类， 通过AsyncHttpResponseHandler回调。
   e). PersistentCookieStore implements CookieStore ——这是一个基于CookieStore的子类， 使用HttpClient处理数据，并且使用cookie持久性存储接口。

   f). RequestParams ——封装了参数处理 例如：

   RequestParams params = new RequestParams();
   params.put("uid", "00001");
   params.put("password", "111111");

   核心操作类：
   a). RetryHandler implements HttpRequestRetryHandler——这是一个多个线程同步处理的类；
   b). SerializableCookie implements Serializable——这是操作cookie 放入/取出数据的类；
   c). SimpleMultipartEntity implements HttpEntity——用于处理多个请求实体封装；
   d). SyncHttpClient extends AsyncHttpClient——同步客户端请求的类；
   e). AsyncHttpClient——异步客户端请求的类。

二.android-async-http实践

1. HttpClientUtil封装类的实现：
   这个class对AsyncHttpClient进行了封装。

public class HttpClientUtil {
    // 实例话对象
    private static AsyncHttpClient client = new AsyncHttpClient();
    static {

        client.setTimeout(11000); // 设置链接超时，如果不设置，默认为10s
    }

    public static AsyncHttpClient getClient() {
        return client;
    }

    // 用一个完整url获取一个string对象
    public static void get(String urlString, AsyncHttpResponseHandler res) {
        client.get(urlString, res);
    }

    // url里面带参数
    public static void get(String urlString, RequestParams params,
            AsyncHttpResponseHandler res) {
        client.get(urlString, params, res);
    }

    // 不带参数，获取json对象或者数组
    public static void get(String urlString, JsonHttpResponseHandler res) {
        client.get(urlString, res);
    }

    // 带参数，获取json对象或者数组
    public static void get(String urlString, RequestParams params,
            JsonHttpResponseHandler res) {
        client.get(urlString, params, res);
    }

    // 下载数据使用，会返回byte数据
    public static void get(String uString, BinaryHttpResponseHandler bHandler) {
        client.get(uString, bHandler);
    }

    //多个url？
    public static void get(String urlString, RequestParams params,
            BinaryHttpResponseHandler bHandler) {
        client.get(urlString, params, bHandler);
    }

    //post
    public static void post(String urlString, RequestParams params,
            ResponseHandlerInterface bHandler) {
        client.post(urlString, params, bHandler);
    }

2. MyImageDownLoader的实现：

提供了下载图片的函数

  public class MyImageDownLoader {

    private static final String TAG = "MyImageDownLoader";

    Context mContext;

    public interface DownLoaderListener {
        public void onResult(int res, String s);
    }

    public MyImageDownLoader() {

    }


  //download image
    public void downloadImage(String uri, String savePath, DownLoaderListener downLoaderListener){  
        // 指定文件类型  
        String[] allowedContentTypes = new String[] { "image/png", "image/jpeg" };  


        HttpClientUtil.get(uri, new ImageResponseHandler(allowedContentTypes,savePath, downLoaderListener));  
      }  

      public class ImageResponseHandler extends BinaryHttpResponseHandler{  
          private String[] allowedContentTypes;  
          private String savePathString;
          DownLoaderListener mDownLoaderListener;

          public ImageResponseHandler(String[] allowedContentTypes, String path, DownLoaderListener downLoaderListener){  
              super();  
              this.allowedContentTypes = allowedContentTypes;  
              savePathString = path;
              mDownLoaderListener = downLoaderListener;
          }  

        @Override
        public void onSuccess(int statusCode, Header[] headers,
                byte[] binaryData) {
            Log.i(TAG, " statusCode=========" + statusCode);
            Log.i(TAG, " statusCode=========" + headers);
            Log.i(TAG, " statusCode====binaryData len=====" + binaryData.length);
            if (statusCode == 200 && binaryData!=null && binaryData.length > 0) {
                boolean b = saveImage(binaryData,savePathString); 
                if (b) {

                    mDownLoaderListener.onResult(0, savePathString);


                }
                else {
                    //fail
                    mDownLoaderListener.onResult(-1, savePathString);
                }
            }
        }
        @Override
        public void onFailure(int statusCode, Header[] headers,
                byte[] binaryData, Throwable error) {
            Log.i(TAG, "download failed");
        }  

        private boolean saveImage(byte[] binaryData, String savePath) {
            Bitmap bmp = BitmapFactory.decodeByteArray(binaryData, 0,  
                    binaryData.length);  

            Log.i(TAG,"saveImage==========" +  savePath);
            File file = new File(savePath);  
            // 压缩格式  
            CompressFormat format = Bitmap.CompressFormat.JPEG;  
            // 压缩比例  
            int quality = 100;  
            try {  
                if (file.createNewFile()){
                    OutputStream stream = new FileOutputStream(file);  
                    // 压缩输出  
                    bmp.compress(format, quality, stream);  
                    stream.close();  
                    return true;
                }

            } catch (IOException e) { 
                Log.i(TAG,"saveImage====003======" +  savePath);
                e.printStackTrace();  
            }  
            Log.i(TAG,"saveImage====004======" +  savePath);
            return false;
        }
      }

}

3. HttpAsyncUploader的实现：

/**
 * 异步上传单个文件
 */
public class HttpAsyncUploader {
    private static final String TAG = "HttpAsyncUploader";

    Context mContext;

    public HttpAsyncUploader() {
    }

    public void uploadFile(String uri, String path) {

        File file = new File(path);
        RequestParams params = new RequestParams();

        try {
            params.put("image", file, "application/octet-stream");

            AsyncHttpClient client = new AsyncHttpClient();

            HttpClientUtil.post(path, params, new AsyncHttpResponseHandler() {
                @Override
                public void onSuccess(int statusCode, Header[] headers,
                        byte[] responseBody) {
                    Log.i(TAG, " statusCode=========" + statusCode);
                    Log.i(TAG, " statusCode=========" + headers);
                    Log.i(TAG, " statusCode====binaryData len====="+ responseBody.length);
                }

                @Override
                public void onFailure(int statusCode, Header[] headers,
                        byte[] responseBody, Throwable error) {
                    Log.i(TAG, " statusCode=========" + statusCode);
                    Log.i(TAG, " statusCode=========" + headers);
                    Log.i(TAG, " statusCode====binaryData len====="+ responseBody.length);
                    Log.i(TAG," statusCode====error====="+ error.getLocalizedMessage());

                }

            });

        } catch (FileNotFoundException e) {

        }
    }
}

4. 调用方法：仅以MyImageDownLoader 来举例说明。

1）MyImageDownLoader 测试函数（在activity中实现）：

private static String URL_PHOTO = "http://img001.us.expono.com/100001/100001-1bc30-2d736f_m.jpg";
private void downloadTest() {
    String url =URL_PHOTO；
    String fileName = "" + System.currentTimeMillis() + ".jpg";
    String savePath = mContext.getCacheDir() + File.separator + fileName;
    MyImageDownLoader mMyImageDownLoader = new MyImageDownLoader();
        // 开始异步下载
    mMyImageDownLoader.downloadImage(
            url,
            savePath,
            new DownLoaderListener() {
                @Override
                public void onResult(int res, String s) {
                    Log.i(TAG,"onResult====res===" + res);
                    Log.i(TAG, "onResult====s===" + s);
                    if (res == 0) {
                        // 下载成功
                        Toast.makeText(mContext, "download success!", Toast.LENGTH_LONG).show();
                        } else {
                            // 下载photo失败
                            Toast.makeText(mContext, "download fail!", Toast.LENGTH_LONG).show();
                        }
                    }
                });
    }

5 项目demo地址：

https://github.com/ranke/HttpAsyncTest/tree/master/code/src/com/util/http

开源的力量是无穷的！