我们正在开发一款基于地理位置的消息应用，使用Parse.com作为后端（类似于Urban Airship / PubNub等），但现在我们希望切换到我们自己的后端以获得更好的控制。为此，我们建立了一个基于node.js的后端，通过REST API公开其功能。
为了使用这个API，我们想要构建一个Android库（类似于Parse.com的Android SDK），它抽象出所有的HTTP请求/响应或REST API调用，并提供各种操作的直接函数，如getUsers()、sendMessage()等。
在Android中实现REST API客户端的方法：
基于2010年Google IO专业技巧，我所见过的最佳实现是RoboSpice库，它是基于REST的，并且非常巧妙地与Activity生命周期一起工作，以避免内存泄漏。
库的快速信息图表在此处：infographic，库本身在此处：here
Service方法可能更好，看看他们使用的robospice service 他们使用一个ExecutorService，当它没有要处理的Requests时终止Service，这比Android更多涉及Java并发。要注意的主要事项是当处理请求时服务在运行，然后如果没有剩余请求，则自行终止。
使用ExecutorService或任何类型的线程池的优点是，你可以定义同时运行多少个请求。除非你有一个非常快速的连接，否则我最多只建议你运行2-4个。
IntentService将其传递到另一个线程，IntentService将在你将其传递给IntentService线程后继续执行。 - Chris.Jenkins/*Copyright 2014 Bhavit Singh Sengar
Licensed under the Apache License, Version 2.0 (the "License");
you may not use this file except in compliance with the License.
You may obtain a copy of the License at
http://www.apache.org/licenses/LICENSE-2.0
Unless required by applicable law or agreed to in writing, software
distributed under the License is distributed on an "AS IS" BASIS,
WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
See the License for the specific language governing permissions and
limitations under the License.*/
package com.infotech.zeus.util;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.HttpClient;
import org.apache.http.client.ResponseHandler;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.BasicResponseHandler;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.protocol.HTTP;
import org.apache.http.util.EntityUtils;
import org.json.JSONException;
import org.json.JSONObject;
import android.widget.Toast;
public class RestClient {
JSONObject data = new JSONObject();
String url;
String headerName;
String headerValue;
public RestClient(String s){
url = s;
}
public void addHeader(String name, String value){
headerName = name;
headerValue = value;
}
public void addParam(String key, String value){
try {
data.put(key, value);
} catch (JSONException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
public String executePost(){ // If you want to use post method to hit server
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setHeader(headerName, headerValue);
HttpResponse response = null;
String result = null;
try {
StringEntity entity = new StringEntity(data.toString(), HTTP.UTF_8);
httpPost.setEntity(entity);
response = httpClient.execute(httpPost);
HttpEntity entity1 = response.getEntity();
result = EntityUtils.toString(entity1);
return result;
//Toast.makeText(MainPage.this, result, Toast.LENGTH_LONG).show();
} catch (UnsupportedEncodingException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return result;
}
public String executeGet(){ //If you want to use get method to hit server
HttpClient httpClient = new DefaultHttpClient();
HttpGet httpget = new HttpGet(url);
String result = null;
ResponseHandler<String> responseHandler = new BasicResponseHandler();
try {
result = httpClient.execute(httpget, responseHandler);
} catch (ClientProtocolException e) {
// TODO Auto-generated catch block
e.printStackTrace();
} catch (IOException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return result;
}
}
一个使用该类的简单示例：
RestClient client = new RestClient("http://www.example.com/demo.php"); //Write your url here
client.addParam("Name", "Bhavit"); //Here I am adding key-value parameters
client.addParam("Age", "23");
client.addHeader("content-type", "application/json"); // Here I am specifying that the key-value pairs are sent in the JSON format
try {
String response = client.executePost(); // In case your server sends any response back, it will be saved in this response string.
} catch (Exception e) {
e.printStackTrace();
}
你也可以使用RESTDroid。它与RoboSpice非常相似，但更易于使用（尽管功能也较少）。
如果您为RESTDroid创建了Parse.com模块，请务必将其添加到GitHub上！
他们在spring framework for android上提供了一个包装器，并提供了一个非常好的处理rest apis的方式。
例子：
用@Background注释替换AsyncTask -> doInBackground()：
@Background
protected void backgroundWork(){
// do something in background
}
用@UiThread替换runOnUiThread和onPostExecute()
@UiThread
protected void uiWork(){
// do something on UI Thread
}
对于REST API
创建REST客户端：
@Rest(rootUrl = "http://company.com/ajax/services",
converters = { MappingJackson2HttpMessageConverter.class })
public interface MyRestClient {
@Get("/events")
EventList getEvents();
}
@RestClient
MyRestClient myRestClient;
public void showAllEvents(){
EventList list = myRestClient.getEvents();
// do something with this list
}