fanfou(饭否） android客户端 代码学习4

参考文档：

http://jiangzhengjun.iteye.com/blog/506041 Java中十六进制转换 Integer.toHexString()
http://blog.csdn.net/ma1kong/article/details/2662997 MessageDigest的功能及用法 .
http://www.linuxidc.com/Linux/2011-09/42288.htm Android中使用SoftReference缓存图片对象
http://apps.hi.baidu.com/share/detail/46467495 HttpClient 4处理文件上传的例子(MultipartEntity) 
http://support.microsoft.com/kb/257591 安全套接字层 (SSL) 握手说明

必备知识：

&和&&都可以用作逻辑与的运算符，表示逻辑与（and），当运算符两边的表达式的结果都为true时，整个运算结果才为true，否则，只要有一方为false，则结果为false。
&&还具有短路的功能，即如果第一个表达式为false，则不再计算第二个表达式，例如，对于if(str != null && !str.equals(“”))表达式，当str为null时，后面的表达式不会执行，所以不会出现NullPointerException如果将&&改为&，则会抛出NullPointerException异常。If(x==33 & ++y>0) y会增长，If(x==33 && ++y>0)不会增长
&还可以用作位运算符，当&操作符两边的表达式不是boolean类型时，&表示按位与操作，我们通常使用0x0f来与一个整数进行&运算，来获取该整数的最低4个bit位，例如，0x31 & 0x0f的结果为0x01。

代码部分：

取得图片流程：url加密..进入图片缓存寻找..未果..通过httpRequest..附带MultipartEntity，时间太晚，不做分类加注释了，自己看吧

/**
	 * 获得指定file/URL对应的Bitmap，首先找本地文件，如果有直接使用，否则去网上获取
	 * 
	 * @param file
	 *            file URL/file PATH
	 * @param bitmap
	 * @param quality
	 * @throws HttpException
	 */
	public Bitmap safeGet(String file) throws HttpException {
		String hashedUrl = getMd5(url);
		FileInputStream fis = null;
		fis = mContext.openFileInput(hashedUrl);
		bitmap=BitmapFactory.decodeStream(fis);
		if (bitmap != null) {
			synchronized (this) { // memory cache
//private Map<String, SoftReference<Bitmap>> mCache;
				mCache.put(file, new SoftReference<Bitmap>(bitmap));
			}
			return bitmap;
		} else { // get from web
			String url = file;
			bitmap = downloadImage2(url);

			// 注释掉以测试新的写入文件方法
			// put(file, bitmap); // file Cache
			return bitmap;
		}
	}


// MD5 hases are used to generate filenames based off a URL.
	private String getMd5(String url) {
		mDigest.update(url.getBytes());

		return getHashString(mDigest);
	}

private String getHashString(MessageDigest digest) {
		StringBuilder builder = new StringBuilder();

		for (byte b : digest.digest()) {
			builder.append(Integer.toHexString((b >> 4) & 0xf));
			builder.append(Integer.toHexString(b & 0xf));
		}

		return builder.toString();
	}

public Response httpRequest(String url,
			ArrayList<BasicNameValuePair> postParams, File file,
			boolean authenticated, String httpMethod) throws HttpException {
		Log.d(TAG, "Sending " + httpMethod + " request to " + url);
		if (TwitterApplication.DEBUG) {
			DebugTimer.betweenStart("HTTP");
		}

		URI uri = createURI(url);

		HttpResponse response = null;
		Response res = null;
		HttpUriRequest method = null;

		// Create POST, GET or DELETE METHOD
		method = createMethod(httpMethod, uri, file, postParams);
		// Setup ConnectionParams, Request Headers
		SetupHTTPConnectionParams(method);

		// Execute Request
		try {
			// 加入OAuth认证信息
			if (authenticated) {
				mOAuthClient.signRequest(method);
			}
			response = mClient.execute(method, localcontext);
			res = new Response(response);
		} catch (ClientProtocolException e) {
			Log.e(TAG, e.getMessage(), e);
			throw new HttpException(e.getMessage(), e);
		} catch (IOException ioe) {
			throw new HttpException(ioe.getMessage(), ioe);
		} catch (OAuthClientException e) {
			Log.e(TAG, e.getMessage(), e);
			throw new HttpException(e.getMessage(), e);
		}

		if (response != null) {
			int statusCode = response.getStatusLine().getStatusCode();
			// It will throw a weiboException while status code is not 200
			HandleResponseStatusCode(statusCode, res);
		} else {
			Log.e(TAG, "response is null");
		}

		if (TwitterApplication.DEBUG) {
			DebugTimer.betweenEnd("HTTP");
		}
		return res;
	}


/**
	 * 创建可带一个File的MultipartEntity
	 * 
	 * @param filename
	 *            文件名
	 * @param file
	 *            文件
	 * @param postParams
	 *            其他POST参数
	 * @return 带文件和其他参数的Entity
	 * @throws UnsupportedEncodingException
	 */
	private MultipartEntity createMultipartEntity(String filename, File file,
			ArrayList<BasicNameValuePair> postParams)
			throws UnsupportedEncodingException {
		MultipartEntity entity = new MultipartEntity();
		// Don't try this. Server does not appear to support chunking.
		// entity.addPart("media", new InputStreamBody(imageStream, "media"));

		entity.addPart(filename, new FileBody(file));
		for (BasicNameValuePair param : postParams) {
			entity.addPart(param.getName(), new StringBody(param.getValue()));
		}
		return entity;
	}