Android http請求例子、Unicode轉UTF-8 java代碼

文章轉自：http://blog.csdn.net/wyzxk888/article/details/7337649

Android項目經常是C/S模型的，因此需要向服務器發出http請求，收藏一個http請求的例子以便以後可以用。

假設發出的請求使用get方法，服務器傳回JSON數據，解析代碼如下：

HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(req_url);
try {
    HttpResponse response = client.execute(httpGet);
    int statusCode = response.getStatusLine().getStatusCode();
    if (statusCode != HttpStatus.SC_OK) {
        Log.d("AD", "statusCode is " + statusCode);
        return null;
    }
    else {
        HttpEntity entity = response.getEntity();
        if (entity != null) {
            InputStream inputStream = entity.getContent();
            StringBuilder builder = new StringBuilder();
            BufferedReader bufferedReader  = new BufferedReader(new InputStreamReader(inputStream));
            for (String s = bufferedReader.readLine(); s != null; s = bufferedReader.readLine()) {
                builder.append(s);
            }
            String result = builder.toString();

            Log.d("AD", "Server return " + result);
            return result;

        }
    }
} catch (Exception e) {
    httpGet.abort();
    Log.d("AD", "when http get, exception is " + e.getMessage());
}
return null;

注：JSON數據格式其實就是String。可以用JSONObject類進行轉化。

有時候服務器傳回的數據中會遇到傳回數據爲Unicode的情況，爲此需要進行Unicode轉UTF-8的轉化，我在項目中遇見過，爲此收藏一份轉化 java 代碼，便於以後使用：

private static String decodeUnicode(String theString) {
    char aChar;
    int len = theString.length();
    StringBuffer outBuffer = new StringBuffer(len);
    for (int x = 0; x < len;) {
        aChar = theString.charAt(x++);
        if (aChar == '\\') {
            aChar = theString.charAt(x++);
            if (aChar == 'u') {
                // Read the xxxx
                int value = 0;
                for (int i = 0; i < 4; i++) {
                    aChar = theString.charAt(x++);
                    switch (aChar) {
                    case '0':
                    case '1':
                    case '2':
                    case '3':
                    case '4':
                    case '5':
                    case '6':
                    case '7':
                    case '8':
                    case '9':
                        value = (value << 4) + aChar - '0';
                        break;
                    case 'a':
                    case 'b':
                    case 'c':
                    case 'd':
                    case 'e':
                    case 'f':
                        value = (value << 4) + 10 + aChar - 'a';
                        break;
                    case 'A':
                    case 'B':
                    case 'C':
                    case 'D':
                    case 'E':
                    case 'F':
                        value = (value << 4) + 10 + aChar - 'A';
                        break;
                    default:
                        throw new IllegalArgumentException(
                                "Malformed   \\uxxxx   encoding.");
                    }

                }
                outBuffer.append((char) value);
            } else {
                if (aChar == 't')
                    aChar = '\t';
                else if (aChar == 'r')
                    aChar = '\r';
                else if (aChar == 'n')
                    aChar = '\n';
                else if (aChar == 'f')
                    aChar = '\f';
                outBuffer.append(aChar);
            }
        } else
            outBuffer.append(aChar);
    }
    return outBuffer.toString();
}