请求服务（RequestService）

一个module中的web组件，负责将Service的结果按照适当的规范输出给前端。
格式：http://server/moduleID/param0/param1/paramN/p.TYPE
格式上包含三部分：
moduleID：将请求分发到具体的模块，分发器参考下面具体介绍；
paramX：参数部分
TYPE：使用什么请求服务完成，对应到module中的一个具体的RequestService

从MVC的角度来看，这个相当于C，将服务提供的模型数据以适当的形式展现给前端；

一、请求分发器
framework中的web组件，一个标准的Http Filter或HttpServlet，下面是Filter版本的代码
public void doFilter(ServletRequest sreq, ServletResponse sresp,
FilterChain chain) throws IOException, ServletException {
HttpServletRequest req = (HttpServletRequest)sreq;
HttpServletResponse resp = (HttpServletResponse)sresp;
req.setAttribute(Constants.SERVLET_CONTEXT, servletContext);
//
String path = req.getRequestURI();
if((path == null || path.length() <= 1) && !StringUtils.isEmpty(welcomePage))
path = this.welcomePage;
//
LocalModule module = null;
String[] uris = null;
String reqType = null;
if(path.indexOf(".") > 0) {
path = path.replaceAll("/+", "/").substring(req.getContextPath().length());
reqType = path.substring(path.lastIndexOf(".") + 1);
final String pathEff = path.substring(0, path.lastIndexOf("."));

uris = StringUtils.split(pathEff, "/");

final String moduleId = uris[0];
module = Application.getInstance().getModules().exists(moduleId)?Application.getInstance().getModules().getLocalModule(moduleId): null;
Principal principal = (Principal)req.getSession().getAttribute(Principal.PRINCIPAL);
if(principal == null && req.getUserPrincipal() != null) {
principal = new SimpleUserPrincipal(req.getUserPrincipal().getName(), req.getUserPrincipal().getName(), req.getUserPrincipal());
}
if(module != null) {
req.setAttribute(Constants.MODULE, module);
Data request = DataUtils.convert(module, req);
ThreadContext ctx = new ThreadContext(module, request, principal);
ThreadContext.setContext(ctx);
}
}
//
if(module != null && !StringUtils.isEmpty(reqType) && module.canHandleRequest(reqType)) {
final String[] pathItems = new String[uris.length - 1];
System.arraycopy(uris, 1, pathItems, 0, uris.length - 1);
processRequestInChain(module, reqType, req, resp, pathItems);
} else {
chain.doFilter(sreq, sresp);
}
}
判断规则：
1、请求的模块存在：Application.getInstance().getModules().exists(moduleId)
2、请求的模块能够处理该类型请求：module.canHandleRequest(reqType)

二、开发RequestService
需要实现接口RequestService：
public interface RequestService {
public void service(LocalModule module, String[] pathItems, HttpServletRequest req, HttpServletResponse resp)
throws ServletException, IOException;
}

一个典型的把服务的处理结果输出为Json的RequestService：
public class JsonRequestService extends AbstractRequestService implements RequestService {

private final static Logger logger = Logger.getLogger(JsonRequestService.class);

public void service(LocalModule module, String[] uris, HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

Data request = DataUtils.convert(module, req);
request.put(Constants.ACTION_TYPE, Constants.ACTION_TYPE_ACTION);
resp.setContentType("application/json");

JSONResult result = new JSONResult();
result.setRequest(request);

String serviceId = uris[0];
if (!module.getModuleConfig().getServiceConfigs().containsKey(serviceId))
serviceId += "Action";
String method = uris[1];
String serviceModuleId = uris.length == 3 ? uris[2] : module.getId();
try {
final Data data = ServiceInvoker.invoke(module.getId(), serviceModuleId, serviceId + ":" + method, request);
String results = (String) data.get("result");
result.setResult(results);
result.setData(data);
} catch (ObjectNotFoundException e) {
resp.sendError(404);
return;
} catch (AppException e) {
logger.error(this.getClass().getName(), e);
result.setResult(e.getErrorCode());
result.setMessage(e.getMessage());
} catch (Exception e) {
logger.error(this.getClass().getName(), e);
result.setResult("1");
result.setMessage(e.getMessage());
}
String jsonString = result.toJSONString();
logger.debug(jsonString);
resp.getWriter().append(jsonString);
resp.flushBuffer();
}

}

三、注册
注册为服务，如下：
<service id="com.flyingwords.framework.request.impl.ShtmlRequestService" type="class" target="com.flyingwords.framework.request.impl.ShtmlRequestService">
<desc></desc>
<configs>
<config name="content-type">text/html; charset=UTF-8</config>
<config name="encoding">UTF-8</config>
</configs>
</service>
注册为RequestService，如下：
<requests>
<request type="json" service="com.flying.framework.request.impl.JsonRequestService"/>
</requests>

四、访问
http://server:port/pas/UserService/findByUserNameAndPassword.json
即可访问该接口了。

flying框架中，RequestService定义为服务的外延，是WEB访问服务的桥梁。