從SOAP遷移到REST

Question

我有一個與C＃網絡服務通信的Android項目。 通信通過HTTPPost（SOAP方式）進行。 我將xml形式的請求發送到服務器，並以xml形式獲取XML形式的響應。 我正在使用以下方法進行通信：

public static BasicHttpResponse getResponse(String uri,
            String SOAPRequestXML) throws ClientProtocolException, Exception {

        HttpPost httppost = new HttpPost(uri);

        StringEntity se = null;
        try {
            se = new StringEntity(SOAPRequestXML, HTTP.UTF_8);
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        se.setContentType("Text/Xml");
        httppost.setHeader("Content-Type", "Text/Xml");

        httppost.setEntity(se);

        HttpClient httpclient = new DefaultHttpClient();
        BasicHttpResponse httpResponse = null;

        httpResponse = (BasicHttpResponse) httpclient.execute(httppost);

        return httpResponse;
    }

現在，我想將此肥皂代碼移至REST。 為此，我需要修改什么？ 我需要在c＃Web服務項目上進行任何更改嗎？ 請說明如何遷移到RestFul服務。

Answer 1

首先請閱讀什么是REST，什么是RestFul： RESTful編程到底是什么？

總而言之，這意味着網址將更改。 不管使用XML還是JSON，都可以快速切換它。

另一件事是，我認為您不應對字符串對象進行操作，而應對可序列化對象進行操作，例如：

Class ContainerWithData implements Serializable {

private Integer a; 

private Integet b;

private String c;

//remeber that it can be null values up here

//Getters and settes below

}

為了避免手動創建代碼，您可以將http://projects.spring.io/spring-android/或Android HTTP客戶端以及Gson或其他庫一起簽出。 某些演示（用於檢查代碼）可以在以下網址找到： https ： //bitbucket.org/bartosz_bednarek/easy-android-and-java-http-client-for-soap-and-restful-api/wiki/Home 。適用於Xml或JSON在Spring庫中有支持，或者您可以找到其他庫。

如果您希望手動創建HTTP客戶端代碼，則有很多可移植性，例如：

Mayby這樣的界面將幫助您：

interface SimpleHttpClient {
    <T> T get(String url, Class<T> classe) throws IOException;  
    <T> T post(String url, Class<T> classe, Serializable contentOrJson) throws IOException; 
    <T> T put(String url, Class<T> classe, Serializable contentOrJson) throws IOException;  
    void delete(String url, Serializable contentOrJson) throws IOException; 
}

在下面可能有例如：

public abstract class EasyHttpClient implements SimpleHttpClient {

        private EasyHttpClientRequest request = new EasyHttpClientRequest();
    private EasyHttpClientGetRequest requestToGet = new EasyHttpClientGetRequest();

    protected synchronized String get(String url) throws IOException {
        return requestToGet.getRequest(url);
    }

    protected synchronized String post(String url, String contentOrJson)
            throws IOException {
        return request.doReguest(url, contentOrJson, "POST", getMimeType());
    }

    protected synchronized String put(String url, String contentOrJson)
            throws IOException {
        return request.doReguest(url, contentOrJson, "PUT", getMimeType());
    }

    protected synchronized void deleteRequest(String url, String contentOrJson) throws IOException {
        request.doReguest(url, contentOrJson, "DELETE", getMimeType());
    }
}

得到：

import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.net.MalformedURLException;
import java.net.URL;
import java.nio.charset.Charset;

public class EasyHttpClientGetRequest {

    public String getRequest(String url) throws MalformedURLException, IOException{
        InputStream is = new URL(url).openStream();
        try {
            BufferedReader rd = new BufferedReader(new InputStreamReader(is,
                    Charset.forName("UTF-8")));
            String jsonText = readAll(rd);
            return jsonText;
        } finally {
            is.close();
        }
    }

    /**
     * Will get {@link String} from {@link Reader} assuming that {@link Byte} in
     * {@link Reader} are char representation.
     */
    private synchronized String readAll(Reader rd) throws IOException {
        StringBuilder sb = new StringBuilder();
        int cp;
        while ((cp = rd.read()) != -1) {
            sb.append((char) cp);
        }
        return sb.toString();
    }
}

其他類似POST / PUT / DELETE：

import java.io.BufferedReader;
import java.io.DataOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.URL;

public final class EasyHttpClientRequest {

    /**
     * Will perform HTTP request to server based on the parameters that has been
     * declared.
     * 
     * @param url
     *            - URL for connect to.
     * @param contentOrJson
     *            - content in String or JSON format
     * @param method
     *            - "DELETE" / "POST" / "PUT" for sending data.
     * @param mime
     *            - mime type in format of Content-Type.
     * @return content of the request as String or null if no content.
     * @throws IOException
     *             if there will be error during communication.
     */
    public synchronized String doReguest(String url, String contentOrJson, String method, String mime)
            throws IOException {
        URL url1;
        HttpURLConnection connection = null;
        try {

            // Create connection
            url1 = new URL(url);
            connection = (HttpURLConnection) url1.openConnection();
            connection.setRequestMethod(method);
            connection.setRequestProperty("Content-Type", mime);

            connection.setRequestProperty("Content-Length",
                    "" + Integer.toString(contentOrJson.getBytes().length));
            connection.setRequestProperty("Content-Language", "en-US");

            connection.setUseCaches(false);
            connection.setDoInput(true);
            connection.setDoOutput(true);

            // Send request
            DataOutputStream wr = new DataOutputStream(connection.getOutputStream());
            wr.writeBytes(contentOrJson);
            wr.flush();
            wr.close();

            // Get Response
            InputStream is = connection.getInputStream();
            BufferedReader rd = new BufferedReader(new InputStreamReader(is));
            String line;
            StringBuffer response = new StringBuffer();
            while ((line = rd.readLine()) != null) {
                response.append(line);
                response.append('\r');
            }
            rd.close();         
            return response.toString();

        } catch (ProtocolException e) {
            return checkProtocolOrReturn(method);
        } catch (Exception e) {
            throw new IOException("Invalid!");
        } finally {
            tryToCloseConnection(connection);
        }
    }



    /**
     * Checks if method is "DELETE" or returns null. It is done bcs DELETE has
     * no content. Invoked after {@link ProtocolException}
     * 
     * @param method
     *            representation ex. "DELETE"
     * @return null if not Delete.
     * @throws IOException
     */
    private String checkProtocolOrReturn(String method) throws IOException {
        if (!method.equals("DELETE")) {
            throw new IOException("Invalid!");
        } else {
            return null;
        }
    }

    /**
     * Will try to close connection if it is not closed already.
     * 
     */
    private void tryToCloseConnection(HttpURLConnection connection) {
        if (connection != null) {
            connection.disconnect();
        }
    }
}

示例中的URL高出可能不是最好的解決方案，因為您必須自己關心授權並記住超時，但這是命題之一。