android基于注解实现类似spring服务端框架

用过spring或Retrofit的人都知道实现函数和http请求的绑定和解耦非常方便，这里分享一下基于NanoHttpd实现的简单注解框架。
第一步定义注解类：

//http控制类，被该注解的类用来处理http请求
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.TYPE)
public @interface Controller {
    //路径前缀，有此前缀的请求会使用此类处理
    String name() default "/"; 
    boolean needPermissonControl() default true;
}

//被该注解的方法用来一个处理http请求
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.METHOD)
public @interface RequestMapping {
    //匹配的路径
    String path() default "";
    Method method() default Method.GET;
}

//该注解用于函数的参数，用于绑定请求的参
@Retention(RetentionPolicy.RUNTIME)
@Target(ElementType.PARAMETER)
public @interface Param {
    //参数名
    String name() default "";
    //参数默认值
    String value() default "";
}

第二步，实现serverlet时注册Controll类

@Override
public void addController(Class controller) {
    // has controller annotation
    if (controller.isAnnotationPresent(Controller.class)) {
        Controller controllerAnnotation = controller.getAnnotation(Controller.class);
        String name = controllerAnnotation.name();
        boolean needPermissionControl = controllerAnnotation.needPermissonControl();
        Method[] methods = controller.getDeclaredMethods();
        // get all request mapping annotation
        for (Method method : methods) {
            if (method.isAnnotationPresent(RequestMapping.class)) {
                RequestMapping requestMapping = method.getAnnotation(RequestMapping.class);
                String path = requestMapping.path();
                org.nanohttpd.protocols.http.request.Method m = requestMapping.method();
                // build full path
                String fullPath = name + File.separatorChar + path;
                // getparams
                ArrayList params = new ArrayList<>();
                Annotation[][] paramAnnotation = method.getParameterAnnotations();
                for (Annotation[] an : paramAnnotation) {
                    if (an.length > 0) {
                        Param p = (Param)an[0];
                        params.add(p);
                    }
                }
                RequestMappingParams requestMappingParams = new RequestMappingParams();
                requestMappingParams.path = fullPath;
                requestMappingParams.handler = controller;
                requestMappingParams.method = m;
                requestMappingParams.methodReflect = method;
                requestMappingParams.params = params;
                requestMappingParams.needPermissionControl = needPermissionControl;
                addRoute(requestMappingParams);
            }
        }
    }
}

大概思路是在注册时，找到Controller注解的uri路径前缀,还有有RequestMapping注解的函数，将路径对应上函数方法，然后在请求来时匹配到该路径就调用对应用的方法，下面是匹配到路径时的处理：

private Response processController(Object object, Map urlParams, IHTTPSession session) throws InvocationTargetException, IllegalAccessException {
    if (requestMappingParams.needPermissionControl) {
        if (!AppNanolets.PermissionEntries.isRemoteAllow(session.getRemoteIpAddress())) {
            return Response.newFixedLengthResponse("not allow");
        }
    }
    //匹配请求方法
    if (requestMappingParams.method != session.getMethod()) {
        return Response.newFixedLengthResponse(Status.INTERNAL_ERROR, "text/plain", "method not supply");
    }
    ArrayList