Android REST webservice 类

　　App与后台交互，后台使用的是Jersey RESTful 服务。在APP端使用Android 内部集成的HttpClient接口，无需引入第三方jar包，

import org.apache.http.client.HttpClient;

在网上找到一个歪果人写Android端的REST类，网上文章引用挺多的。

Calling Web Services in Android using HttpClient

public class RestClient {

    private ArrayList <NameValuePair> params;
    private ArrayList <NameValuePair> headers;

    private String url;

    private int responseCode;
    private String message;

    private String response;

    public String getResponse() {
        return response;
    }

    public String getErrorMessage() {
        return message;
    }

    public int getResponseCode() {
        return responseCode;
    }

    public RestClient(String url)
    {
        this.url = url;
        params = new ArrayList<NameValuePair>();
        headers = new ArrayList<NameValuePair>();
    }

    public void AddParam(String name, String value)
    {
        params.add(new BasicNameValuePair(name, value));
    }

    public void AddHeader(String name, String value)
    {
        headers.add(new BasicNameValuePair(name, value));
    }

    public void Execute(RequestMethod method) throws Exception
    {
        switch(method) {
            case GET:
            {
                //add parameters
                String combinedParams = "";
                if(!params.isEmpty()){
                    combinedParams += "?";
                    for(NameValuePair p : params)
                    {
                        String paramString = p.getName() + "=" + URLEncoder.encode(p.getValue(),”UTF-8″);
                        if(combinedParams.length() > 1)
                        {
                            combinedParams  +=  "&" + paramString;  // 如何不是添加第一个key-value时
                        }
                        else
                        {
                            combinedParams += paramString;   // 添加第一个key-value
                        }
                    }
                }

                HttpGet request = new HttpGet(url + combinedParams);

                //add headers
                for(NameValuePair h : headers)
                {
                    request.addHeader(h.getName(), h.getValue());
                }

                executeRequest(request, url);
                break;
            }
            case POST:
            {
                HttpPost request = new HttpPost(url);

                //add headers
                for(NameValuePair h : headers)
                {
                    request.addHeader(h.getName(), h.getValue());
                }

                if(!params.isEmpty()){
                    request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));
                }

                executeRequest(request, url);
                break;
            }
        }
    }

    private void executeRequest(HttpUriRequest request, String url)
    {
        HttpClient client = new DefaultHttpClient();

        HttpResponse httpResponse;

        try {
            httpResponse = client.execute(request);
            responseCode = httpResponse.getStatusLine().getStatusCode();
            message = httpResponse.getStatusLine().getReasonPhrase();

            HttpEntity entity = httpResponse.getEntity();

            if (entity != null) {

                InputStream instream = entity.getContent();
                response = convertStreamToString(instream);

                // Closing the input stream will trigger connection release
                instream.close();
            }

        } catch (ClientProtocolException e)  {
            client.getConnectionManager().shutdown();
            e.printStackTrace();
        } catch (IOException e) {
            client.getConnectionManager().shutdown();
            e.printStackTrace();
        }
    }

    private static String convertStreamToString(InputStream is) {

        BufferedReader reader = new BufferedReader(new InputStreamReader(is));
        StringBuilder sb = new StringBuilder();

        String line = null;
        try {
            while ((line = reader.readLine()) != null) {
                sb.append(line + "\n");
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                is.close();
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
        return sb.toString();
    }
}

调用实例：

RestClient client = new RestClient(LOGIN_URL);
client.AddParam("accountType", "GOOGLE");
client.AddParam("source", "tboda-widgalytics-0.1");
client.AddParam("Email", _username);
client.AddParam("Passwd", _password);
client.AddParam("service", "analytics");
client.AddHeader("GData-Version", "2");

try {
    client.Execute(RequestMethod.POST);
} catch (Exception e) {
    e.printStackTrace();
}

String response = client.getResponse();

GET 方法没有问题，但是POST方法就需要考虑了，因为传递内容并不是只有

request.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));

比如自己的项目中使用的是：request.setEntity(new StringEntity(obj.toString(),HTTP.UTF_8));

这里的 setEntity 内容是和setHeader 有关系的。

我的项目中应用的两种：postRequest.addHeader("Content-Type", "multipart/mixed");

post 图片的header 

MultipartEntity reqEntity = new MultipartEntity();
reqEntity.addPart("uploaded", bab);
postRequest.setEntity(reqEntity);

POST json 对象的：header 说明

rest.AddHeaders("Content-Type","application/json;charset=utf8");

Entity这样设置的：

request.setEntity(new StringEntity(obj.toString(),HTTP.UTF_8));

所以这个类写的通用型不行。