原文链接：http://www.cnblogs.com/VinC/archive/2011/02/24/1964049.html
本章目的: 用Wcf建立可以上Android可以访问的数据服务, 数据传输格式采用比较适合于移动互联网传输的Json格式.
服务的开发流程我们按照 服务契约(ServiceContract), 服务实现(Service), 实体对象模型(Model) 及服务发布的流程来介绍.
由于自己对Http请求的链接认识的比较浅,对于有些问题没法做出清楚明了的解释, Android访问WCF这篇文章我会贴出来代码, 让后说明一下关注的地方, 不做深入研究.
一. 服务契约(Contract)
[ServiceContract]
public interface IAccountJsonService
{
[OperationContract(Name = "GetAccountDataJson")]
[WebGet(RequestFormat = WebMessageFormat.Json, ResponseFormat = WebMessageFormat.Json, UriTemplate = "GetAccountData", BodyStyle = WebMessageBodyStyle.Bare)]
List<Account> GetAccountData();
[OperationContract(Name = "SendMessageJson")]
[WebInvoke(Method = "GET", ResponseFormat = WebMessageFormat.Json, UriTemplate = "SendMessage/{Message}", BodyStyle = WebMessageBodyStyle.Bare)]
string SendMessage(string Message);
}
此契约定义了两个方法, GetAccountData(获取Account数据列表, 方法不带参数), SendMessage, 获取从客户端传过来的数据, 并返回;
1. 这里面注意WebInvoke(SendMessage方法)这个Attribute, Method代表了Http的访问方法, 我们这是从服务器获取数据，是请求数据， 所以用GET, 这个也可以用另外一个Attribute来替代-WebGet(GetAccountData方法);
2. 我们要给客户端返回Json数据,我们只需在WebInvoke or WebGet Attribute中指定ResponseFormat的格式即可, 这个从名字命名就可以看出来是制定返回的数据格式的.
3. 要注意UriTemplate属性, 这个是指定我们请求时的方法路径, 后面给出示例.
二. 服务实现(Service)
public class AccountService : IAccountJsonService
{
public List<Account> GetAccountData()
{
return MockAccount.AccountList;
}
public string SendMessage(string Message)
{
return " Message:" + Message;
}
}
此处只是实现了IAccountJsonService接口.
三. 实体对象模型&模拟数据
实体类定义:
[DataContract]
public class Account
{
[DataMember]
public string Name { get; set; }
[DataMember]
public int Age { get; set; }
[DataMember]
public string Address { get; set; }
[DataMember]
public DateTime Birthday { get; set; }
}
模拟数据:
public class MockAccount
{
public static List<Account> AccountList
{
get
{
var list = new List<Account>();
list.Add(new Account { Name = "Bill Gates", Address = "YouYi East Road", Age = 56, Birthday = DateTime.Now });
list.Add(new Account { Name = "Steve Paul Jobs", Address = "YouYi West Road", Age = 57, Birthday = DateTime.Now });
list.Add(new Account { Name = "John D. Rockefeller", Address = "YouYi North Road", Age = 65, Birthday = DateTime.Now });
return list;
}
}
}
模拟数据返回一个Account的列表, 含有三条模拟数据, Birthday用DateTime.Now可是随时查看数据是不是最新生成的.
四. 服务发布
在这个例子里面, 我们的服务采用Console的发布形式, 如果采用IIS发布, 只要参考WCF的服务配置信息, 在IIS环境下配置就OK了.
WCF配置信息
<system.serviceModel>
<behaviors>
<serviceBehaviors>
<behavior name="">
<serviceMetadata httpGetUrl="mex" httpGetEnabled="true"/>
<serviceDebug httpHelpPageEnabled="true" includeExceptionDetailInFaults="true"/>
</behavior>
</serviceBehaviors>
<endpointBehaviors>
<behavior name="WebHttpBindingBehavior">
<webHttp/>
</behavior>
</endpointBehaviors>
</behaviors>
<services>
<service name="Hosting.AccountService">
<endpoint address="xml" binding="webHttpBinding" contract="Hosting.IAccountXmlService" behaviorConfiguration="WebHttpBindingBehavior"/>
<!--<endpoint address="json" binding="webHttpBinding" contract="Hosting.IAccountJsonService" behaviorConfiguration="WebHttpBindingBehavior"/>-->
<host>
<baseAddresses>
<add baseAddress="http://127.0.0.1:82/AccountService"/>
</baseAddresses>
</host>
</service>
</services>
</system.serviceModel>
控制台进行服务的托管发布
class Program
{
static void Main(string[] args)
{
using (ServiceHost host = new ServiceHost(typeof(AccountService)))
{
host.Open();
Console.WriteLine("AccountService Address:");
foreach (var endpoint in host.Description.Endpoints)
{
Console.WriteLine(endpoint.Address.ToString());
}
Console.WriteLine("AccountService Started,Press any key to stop service...");
Console.ReadKey();
host.Close();
}
}
}
下篇将介绍Android如何访问我们编写的服务.
此部分分为 建立Http请求 跟 接受WCF 返回的数据.
一. 建立Http请求的方法
protected String getRequest(String url, DefaultHttpClient client)
throws Exception {
String result = null;
int statusCode = 0;
HttpGet getMethod = new HttpGet(url);
Log.d(TAG, "do the getRequest,url=" + url + "");
try {
getMethod.setHeader("User-Agent", USER_AGENT);
// HttpParams params = new HttpParams();
// 添加用户密码验证信息
// client.getCredentialsProvider().setCredentials(
// new AuthScope(null, -1),
// new UsernamePasswordCredentials(mUsername, mPassword));
HttpResponse httpResponse = client.execute(getMethod);
// statusCode == 200 正常
statusCode = httpResponse.getStatusLine().getStatusCode();
Log.d(TAG, "statuscode = " + statusCode);
// 处理返回的httpResponse信息
result = retrieveInputStream(httpResponse.getEntity());
} catch (Exception e) {
Log.e(TAG, e.getMessage());
throw new Exception(e);
} finally {
getMethod.abort();
}
return result;
}
参数URL: 我们要请求的地址
Client: 这个可以直接用new DefaultHttpClient(new BasicHttpParams()) 来初始化.
这个方法中需要注意RetrieveInputStream方法, 这个是当Http请求完成之后, 用来处理服务器返回数据的方法,
二. 接受从WCF端传回的数据
protected String retrieveInputStream(HttpEntity httpEntity) {
int length = (int) httpEntity.getContentLength();
if (length < 0)
length = 10000;
StringBuffer stringBuffer = new StringBuffer(length);
try {
InputStreamReader inputStreamReader = new InputStreamReader(
httpEntity.getContent(), HTTP.UTF_8);
char buffer[] = new char[length];
int count;
while ((count = inputStreamReader.read(buffer, 0, length - 1)) > 0) {
stringBuffer.append(buffer, 0, count);
}
} catch (UnsupportedEncodingException e) {
Log.e(TAG, e.getMessage());
} catch (IllegalStateException e) {
Log.e(TAG, e.getMessage());
} catch (IOException e) {
Log.e(TAG, e.getMessage());
}
return stringBuffer.toString();
}
此方法在接受到WCF服务端返回的数据之后, 转换程String类型返回.
附加内容:
请求数据之前封装方法:
private static final String BASE_URL = "http://10.0.2.2:82/BlogCategoryService/";
private static final String EXTENSION = "Json/";;
private static final String TAG = "API";
private static final String USER_AGENT = "Mozilla/4.5";
public JSONObject getObject(String sbj) throws JSONException, Exception {
return new JSONObject(getRequest(BASE_URL + EXTENSION + sbj));
}
public JSONArray getArray(String sbj) throws JSONException,
Exception {
return new JSONArray(getRequest(BASE_URL + EXTENSION + sbj));
}
protected String getRequest(String url) throws Exception {
return getRequest(url, new DefaultHttpClient(new BasicHttpParams()));
}
总结 ： 此篇主要说明了Http请求的的两个阶段, 建立请求跟接受服务器返回的数据, 在下篇再主要说明如何处理服务端返回的JSON数据,并把数据显示在UI上面.