我目前正在JDK 1.8.0-40上运行Glassfish 4.1。我使用的是javaee-web-api-7.0和jersey-media-moxy-2.22。我正在从/向JAXB注释的java对象编组/解组JSON和XML。
我设置了ContextResolver<Unmarshaller>以提供Unmarshaller自定义ValidationEventHandler，它将从属性设置器中收集异常并抛出BadRequestException以及聚合验证错误。这部分正在运作。
但是，我在检查未设置属性的对象上也有beforeMarshal和afterUnmarshal方法（必须设置属性的规则因属性值而异，导致我排除对模式的验证）。如果afterUnmarshal方法引发异常，则ValidationEventHandler不会看到异常，而是ExceptionMapper冒充。
有没有办法从单个对象的beforeMarshal和afterUnmarshal方法中捕获异常，并将它们转到ValidationEventHandler？
我认为可以实现MessageBodyReader来捕获异常，使用Unmarshaller.getEventHandler，手动调用ValidationEventHandler.handleEvent，然后抛出BadRequestException { {1}}返回false [编辑：如果从handleEvent抛出异常，则无法继续解组，因此唯一可能的办法是终止处理]。但这会遗漏事件位置信息，我并不特别想要实现我自己的Unmarshaller.unmarshal。我希望有一种更简单的内置方式来做到这一点，我无法发现。
提前感谢您的帮助。
答案 0 :(得分：2)
经过一番挖掘和头痛之后，我最终开发了一个解决方案。
编辑：您无需修补Jersey以实现此行为。我无法在任何地方找到它，但org.glassfish.jersey.internal.inject.Custom注释将提供者标记为自定义（而@Provider单独是不够的）。如果您的提供者是CommonProperties.MOXY_JSON_FEATURE_DISABLE，则还必须将application/json设置为true来禁用MOXy。因此，您只需要这样做：
@Custom
@Provider
public class MyCustomMessageBodyReader...
[...]
<击>
这是我最不喜欢的解决方案的一部分，但也让我免于一堆代码重复。 Jersey的选择MessageBodyReader/Writers的排序算法无法确定应用程序提供程序的优先级（我可以找到）。我想扩展AbstractRootElementJaxbProvider以重用其功能，但这意味着我无法使其比Jersey提供的XmlRootElementJaxbProvider更具体。因为默认情况下，Jersey仅对媒体类型距离，对象类型距离以及提供者是否注册为自定义提供者（通过@Provider注释检测到的提供者未注册为自定义提供者）进行排序，因此Jersey实施将始终选择而不是我的MessageBodyReader/Writer。
我从Github检查了Jersey 2.10.4来源并修补MessageBodyFactory以使用@Priority注释作为MessageBodyReader/Writers选择算法的一部分。
diff --git a/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java b/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java
index 3845b0c..110f18c 100644
--- a/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java
+++ b/core-common/src/main/java/org/glassfish/jersey/message/internal/MessageBodyFactory.java
@@ -72,6 +72,7 @@ import javax.ws.rs.ext.MessageBodyWriter;
import javax.ws.rs.ext.ReaderInterceptor;
import javax.ws.rs.ext.WriterInterceptor;
+import javax.annotation.Priority;
import javax.inject.Inject;
import javax.inject.Singleton;
import javax.xml.transform.Source;
@@ -107,6 +108,8 @@ import jersey.repackaged.com.google.common.primitives.Primitives;
*/
public class MessageBodyFactory implements MessageBodyWorkers {
+ private static final int DEFAULT_WORKER_PRIORITY = 1000;
+
private static final Logger LOGGER = Logger.getLogger(MessageBodyFactory.class.getName());
/**
@@ -218,13 +221,15 @@ public class MessageBodyFactory implements MessageBodyWorkers {
public final T provider;
public final List<MediaType> types;
public final Boolean custom;
+ public final int priority;
public final Class<?> providerClassParam;
protected WorkerModel(
- final T provider, final List<MediaType> types, final Boolean custom, Class<T> providerType) {
+ final T provider, final List<MediaType> types, final Boolean custom, final int priority, Class<T> providerType) {
this.provider = provider;
this.types = types;
this.custom = custom;
+ this.priority = priority;
this.providerClassParam = getProviderClassParam(provider, providerType);
}
@@ -239,8 +244,8 @@ public class MessageBodyFactory implements MessageBodyWorkers {
private static class MbrModel extends WorkerModel<MessageBodyReader> {
- public MbrModel(MessageBodyReader provider, List<MediaType> types, Boolean custom) {
- super(provider, types, custom, MessageBodyReader.class);
+ public MbrModel(MessageBodyReader provider, List<MediaType> types, Boolean custom, int priority) {
+ super(provider, types, custom, priority, MessageBodyReader.class);
}
public boolean isReadable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
@@ -263,8 +268,8 @@ public class MessageBodyFactory implements MessageBodyWorkers {
private static class MbwModel extends WorkerModel<MessageBodyWriter> {
- public MbwModel(MessageBodyWriter provider, List<MediaType> types, Boolean custom) {
- super(provider, types, custom, MessageBodyWriter.class);
+ public MbwModel(MessageBodyWriter provider, List<MediaType> types, Boolean custom, int priority) {
+ super(provider, types, custom, priority, MessageBodyWriter.class);
}
public boolean isWriteable(Class<?> type, Type genericType, Annotation[] annotations, MediaType mediaType) {
@@ -437,6 +442,10 @@ public class MessageBodyFactory implements MessageBodyWorkers {
if (modelA.custom ^ modelB.custom) {
return (modelA.custom) ? -1 : 1;
}
+
+ if(modelA.priority != modelB.priority) {
+ return modelA.priority - modelB.priority;
+ }
return 0;
}
@@ -578,17 +587,27 @@ public class MessageBodyFactory implements MessageBodyWorkers {
}
}
+ private static int getPriority(Priority annotation) {
+ if (annotation == null) {
+ return DEFAULT_WORKER_PRIORITY;
+ }
+
+ return annotation.value();
+ }
+
private static void addReaders(List<MbrModel> models, Set<MessageBodyReader> readers, boolean custom) {
for (MessageBodyReader provider : readers) {
+ int priority = getPriority(provider.getClass().getAnnotation(Priority.class));
List<MediaType> values = MediaTypes.createFrom(provider.getClass().getAnnotation(Consumes.class));
- models.add(new MbrModel(provider, values, custom));
+ models.add(new MbrModel(provider, values, custom, priority));
}
}
private static void addWriters(List<MbwModel> models, Set<MessageBodyWriter> writers, boolean custom) {
for (MessageBodyWriter provider : writers) {
+ int priority = getPriority(provider.getClass().getAnnotation(Priority.class));
List<MediaType> values = MediaTypes.createFrom(provider.getClass().getAnnotation(Produces.class));
- models.add(new MbwModel(provider, values, custom));
+ models.add(new MbwModel(provider, values, custom, priority));
}
}
<击>
在构建Jersey之后，我用我的修补版本替换了Glassfish模块目录中的jersey-common jar。这让我用MessageBodyReader/Writers注释我的@Priority(500)并让泽西选择它们。
我觉得这是让我优先考虑MessageBodyReader/Writers而不影响依赖于泽西岛的Glassfish其他任何东西的最简洁方法。
受this post的启发我决定使用Unmarshaller.Listener比我在每个JAXB类上实现afterUnmarshal的原始路径更清晰。我创建了一个接口（CanBeValidated）和扩展Unmarshaller.Listener，如下所示。
public final class ValidatingUnmarshallerListener
extends Unmarshaller.Listener
{
private final ValidationEventHandler validationEventHandler;
public ValidatingUnmarshallerListener(
ValidationEventHandler validationEventHandler)
{
this.validationEventHandler = validationEventHandler;
}
@Override
public void afterUnmarshal(Object target, Object parent)
{
if (target == null
|| !(target instanceof CanBeValidated))
{
return;
}
CanBeValidated v = (CanBeValidated) target;
Collection<Throwable> validationErrors = v.validate();
for (Throwable t : validationErrors)
{
ValidationEvent event = new ValidationEventImpl(
ValidationEvent.ERROR,
t.getLocalizedMessage(),
null,
t);
this.validationEventHandler.handleEvent(event);
}
}
}
最后，我扩展了org.glassfish.jersey.message.internal.AbstractRootElementJaxbProvider以覆盖readFrom方法。
@Override
protected Object readFrom(
Class<Object> type,
MediaType mediaType,
Unmarshaller u,
InputStream entityStream)
throws JAXBException
{
final SAXSource source = getSAXSource(spf.provide(), entityStream);
ValidationEventCollector eventCollector = new ValidationEventCollector();
ValidatingUnmarshallerListener listener = new ValidatingUnmarshallerListener(eventCollector);
u.setEventHandler(eventCollector);
u.setListener(listener);
final Object result;
if (type.isAnnotationPresent(XmlRootElement.class))
{
result = u.unmarshal(source);
}
else
{
result = u.unmarshal(source, type).getValue();
}
if (eventCollector.hasEvents())
{
HttpError error = new HttpError(Response.Status.BAD_REQUEST);
for (ValidationEvent event : eventCollector.getEvents())
{
error.addMessage(ValidationUtil.toString(event));
}
throw new WebApplicationException(error.toResponse());
}
return result;
}