[英]How to get resource method matched to URI before Jersey invokes it?
我正在嘗試實現一個ContainerRequestFilter
,它對請求的參數進行自定義驗證。 我需要查找將與URI匹配的資源方法,以便我可以從方法的參數中刪除自定義注釋。
根據這個答案,我應該能夠注入ExtendedUriInfo
,然后使用它來匹配方法:
public final class MyRequestFilter implements ContainerRequestFilter {
@Context private ExtendedUriInfo uriInfo;
@Override
public ContainerRequest filter(ContainerRequest containerRequest) {
System.out.println(uriInfo.getMatchedMethod());
return containerRequest;
}
}
但getMatchedMethod
顯然會返回null
,一直到實際調用該方法為止(此時對我來說進行驗證為時已晚)。
在調用資源方法之前,如何檢索將與給定URI匹配的Method
?
對於那些感興趣的人,我正在嘗試推出我自己的必需參數驗證,如JERSEY-351中所述 。
實際上,您應該嘗試將ResourceInfo
注入自定義請求過濾器。 我已經嘗試過RESTEasy,它在那里工作。 優點是您針對JSR接口而不是Jersey實現進行編碼。
public class MyFilter implements ContainerRequestFilter
{
@Context
private ResourceInfo resourceInfo;
@Override
public void filter(ContainerRequestContext requestContext)
throws IOException
{
Method theMethod = resourceInfo.getResourceMethod();
return;
}
}
我想出了如何使用Jersey解決我的問題。 顯然沒有辦法將請求的URI與調用該方法之前匹配的方法相匹配,至少在Jersey 1.x中是這樣。 但是,我能夠使用ResourceFilterFactory
創建ResourceFilter
為每個資源的方法-這樣這些過濾器可以知道時間提前的目的方法。
這是我的解決方案,包括對所需查詢參數的驗證(使用Guava和JSR 305):
public final class ValidationFilterFactory implements ResourceFilterFactory {
@Override
public List<ResourceFilter> create(AbstractMethod abstractMethod) {
//keep track of required query param names
final ImmutableSet.Builder<String> requiredQueryParamsBuilder =
ImmutableSet.builder();
//get the list of params from the resource method
final ImmutableList<Parameter> params =
Invokable.from(abstractMethod.getMethod()).getParameters();
for (Parameter param : params) {
//if the param isn't marked as @Nullable,
if (!param.isAnnotationPresent(Nullable.class)) {
//try getting the @QueryParam value
@Nullable final QueryParam queryParam =
param.getAnnotation(QueryParam.class);
//if it's present, add its value to the set
if (queryParam != null) {
requiredQueryParamsBuilder.add(queryParam.value());
}
}
}
//return the new validation filter for this resource method
return Collections.<ResourceFilter>singletonList(
new ValidationFilter(requiredQueryParamsBuilder.build())
);
}
private static final class ValidationFilter implements ResourceFilter {
final ImmutableSet<String> requiredQueryParams;
private ValidationFilter(ImmutableSet<String> requiredQueryParams) {
this.requiredQueryParams = requiredQueryParams;
}
@Override
public ContainerRequestFilter getRequestFilter() {
return new ContainerRequestFilter() {
@Override
public ContainerRequest filter(ContainerRequest request) {
final Collection<String> missingRequiredParams =
Sets.difference(
requiredQueryParams,
request.getQueryParameters().keySet()
);
if (!missingRequiredParams.isEmpty()) {
final String message =
"Required query params missing: " +
Joiner.on(", ").join(missingRequiredParams);
final Response response = Response
.status(Status.BAD_REQUEST)
.entity(message)
.build();
throw new WebApplicationException(response);
}
return request;
}
};
}
@Override
public ContainerResponseFilter getResponseFilter() {
return null;
}
}
}
並且ResourceFilterFactory
在Jersey中注冊為web.xml
servlet的init參數:
<init-param>
<param-name>com.sun.jersey.spi.container.ResourceFilters</param-name>
<param-value>my.package.name.ValidationFilterFactory</param-value>
</init-param>
在啟動時,將為Jersey檢測到的每個資源方法調用ValidationFilterFactory.create
。
感謝這篇文章讓我走上正軌: 如何在Jersey ContainerResponseFilter中獲取資源注釋
我知道你正在尋找一個僅限澤西島的解決方案,但這里有一個Guice方法可以讓事情有效:
public class Config extends GuiceServletContextListener {
@Override
protected Injector getInjector() {
return Guice.createInjector(
new JerseyServletModule() {
@Override
protected void configureServlets() {
bindInterceptor(Matchers.inSubpackage("org.example"), Matchers.any(), new ValidationInterceptor());
bind(Service.class);
Map<String, String> params = Maps.newHashMap();
params.put(PackagesResourceConfig.PROPERTY_PACKAGES, "org.example");
serve("/*").with(GuiceContainer.class, params);
}
});
}
public static class ValidationInterceptor implements MethodInterceptor {
public Object invoke(MethodInvocation method) throws Throwable {
System.out.println("Validating: " + method.getMethod());
return method.proceed();
}
}
}
@Path("/")
public class Service {
@GET
@Path("service")
@Produces({MediaType.TEXT_PLAIN})
public String service(@QueryParam("name") String name) {
return "Service " + name;
}
}
編輯:性能比較:
public class AopPerformanceTest {
@Test
public void testAopPerformance() {
Service service = Guice.createInjector(
new AbstractModule() {
@Override
protected void configure() { bindInterceptor(Matchers.inSubpackage("org.example"), Matchers.any(), new ValidationInterceptor()); }
}).getInstance(Service.class);
System.out.println("Total time with AOP: " + timeService(service) + "ns");
}
@Test
public void testNonAopPerformance() {
System.out.println("Total time without AOP: " + timeService(new Service()) + "ns");
}
public long timeService(Service service) {
long sum = 0L;
long iterations = 1000000L;
for (int i = 0; i < iterations; i++) {
long start = System.nanoTime();
service.service(null);
sum += (System.nanoTime() - start);
}
return sum / iterations;
}
}
在RestEasy的-JAXRS-3.0.5,您可以檢索ResourceMethodInvoker
表示從匹配資源的方法ContainerRequestContext.getProperty()
一內部ContainerRequestFilter
:
import org.jboss.resteasy.core.ResourceMethodInvoker;
public class MyRequestFilter implements ContainerRequestFilter
{
public void filter(ContainerRequestContext request) throws IOException
{
String propName = "org.jboss.resteasy.core.ResourceMethodInvoker";
ResourceMethodInvoker invoker = (ResourceMethodInvoker)request.getProperty();
invoker.getMethod().getParameterTypes()....
}
}
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