resteasy自定义参数解析

• InjectorFactory：负责创建注入的工厂，比如ValueInject、MethodInjector
• ValueInjector：处理参数解析
  要扩展自定义的参数解析，基本思路是这样，使用特定的InejectorFactory创建自定义的ValueInjector。
  resteasy框架允许我们使用自已的InjectorFactory，默认是使用InjectorFactoryImpl。如果我们想改变其默认实现，需要在web.xml中指定具体的实现类，这部分的源码在ConfigurationBootstrap#createDeployment方法中，支持自定义的InjectorFactory

web.xml <context-param>    <param-name>resteasy.injector.factory</param-name>    <param-value>net.dwade.plugins.resteasy.PaymentInjectorFactory</param-value> </context-param>

编写PaymentInjectorFactory实现类，继承InjectorFactoryImpl，重写createParameterExtractor方法，返回自定义的ValueInjector实现类。

PaymentInjectorFactory.java/*** 扩展resteasy的{@link InjectorFactory}，用于实现自定义参数解析、参数验证，* 如果使用{@link SpringResteasyBootstrap}作为ServletContextListener启动，默认会使用该InjectorFactory，* 否则需要在web.xml中指定resteasy.injector.factory参数, eg:* <pre>* &lt;context-param&gt;*    &lt;param-name&gt;resteasy.injector.factory&lt;/param-name&gt;*    &lt;param-value&gt;com.sitech.miso.payment.common.support.rest.PaymentInjectorFactory&lt;/param-value&gt;* &lt;/context-param&gt;* </pre>* @see SpringResteasyBootstrap* @see ResteasyBootstrap* @see ListenerBootstrap#createDeployment()* @author huangxf* @date 2017年4月21日*/public class PaymentInjectorFactory extends InjectorFactoryImpl {    @Override    public ValueInjector createParameterExtractor(Parameter parameter,            ResteasyProviderFactory providerFactory) {        boolean isDataBody = hasAnnotation( parameter, RequestDataBody.class );        if ( isDataBody ) {            return new RequestDataInjector( parameter, providerFactory );        }        return super.createParameterExtractor(parameter, providerFactory);    }    /**    * 返回{@link PaymentMethodInjector}    */    @Override    public MethodInjector createMethodInjector(ResourceLocator method,            ResteasyProviderFactory factory) {        return new PaymentMethodInjector( method, factory );    }    @SuppressWarnings("rawtypes")    protected boolean hasAnnotation( Parameter parameter, Class annotation ) {        Annotation[] annotations = parameter.getAnnotations();        if ( annotations == null ) {            return false;        }        for ( Annotation anno : annotations ) {            boolean is = annotation.isInstance( anno );            if ( is ) {                return true;            }        }        return false;    }}

实现ValueInjector接口，完成参数解析的逻辑，这里以获取json报文中的data节点为例。

RequestDataInjector.java/*** 支持resteasy对{@link RequestDataBody}注解的参数解析* @see RequestDataBody* @author huangxf* @date 2017年4月21日*/public class RequestDataInjector implements ValueInjector {    private Parameter paramerter;    private ResteasyProviderFactory providerFactory;    private Logger logger = LoggerFactory.getLogger( this.getClass() );    /**    * 保存请求json数据的key，value为JSONObject    */    public static final String JSON_KEY = RequestDataInjector.class.getName();    public RequestDataInjector(Parameter parameter,    ResteasyProviderFactory providerFactory) {        this.paramerter = parameter;        this.providerFactory = providerFactory;    }    @Override    public Object inject( HttpRequest request, HttpResponse response ) {        Throwable ex = null;        try {            checkJsonRequest( request );            JSONObject jsonObject = (JSONObject)request.getAttribute( JSON_KEY );            //说明方法中的参数未被解析，因为可能需要对Sign进行解析            if ( jsonObject == null  ) {                //获取请求数据中的json                String json = JSON.parseObject( request.getInputStream(), StandardCharsets.UTF_8, String.class );                logger.info( "解析Json数据:{}", json );                //转换成json对象                jsonObject = JSONObject.parseObject( json );                //保存至上下文中，便于其他参数的解析                request.setAttribute( JSON_KEY, jsonObject );            }            //将data节点下面的数据返回            return jsonObject.getJSONObject( "data" ).toJavaObject( paramerter.getType() );        } catch ( Exception e ) {            ex = e;            logger.warn( "请求参数有误.", e );        }        throw new IllegalArgumentException( "Request param error.", ex );    }    /**    * 检验是否传递的是json数据    */    protected void checkJsonRequest( HttpRequest request ) {        String contentType = request.getHttpHeaders().getHeaderString( "Content-Type" );        //匹配application/json，text/json        if ( StringUtils.containsIgnoreCase( contentType, "json" ) ) {            return;        }        throw new IllegalArgumentException( "Not json request." );    }    @Override    public Object inject() {        throw new RuntimeException("Not allowed to inject.");    }}