Java SerializerResult.getContent方法代码示例

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
private void writeProperty(ODataRequest request, ODataResponse response, ContentType responseFormat,
		EdmEntitySet edmEntitySet, String edmPropertyName, EdmPrimitiveType edmPropertyType, Property property)
		throws SerializerException, ODataApplicationException {
	Object value = property.getValue();
	if (value != null) {

		// 3.1. configure the serializer
		ODataSerializer serializer = odata.createSerializer(responseFormat);
		ContextURL contextUrl = null;
		try {
			//Need absolute URI for PowewrQuery and Linqpad (and probably other MS based OData clients)
			contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName)
					.serviceRoot(new URI(request.getRawBaseUri() + "/")).build();
		} catch (URISyntaxException e) {
			throw new ODataApplicationException("Inavlid RawBaseURI " + request.getRawBaseUri(),
					HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ROOT);
		}

		PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
		// 3.2. serialize
		SerializerResult serializerResult = serializer.primitive(serviceMetadata, edmPropertyType, property,
				options);
		InputStream propertyStream = serializerResult.getContent();

		//4. configure the response object
		response.setContent(propertyStream);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	} else {
		// in case there's no value for the property, we can skip the serialization
		response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
	}
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType responseFormat)
						throws ODataApplicationException, SerializerException {

	// 1. retrieve the Entity Type
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// Note: only in our example we can assume that the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0);
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	// 2. retrieve the data from backend
	List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
	Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);

	// 3. serialize
	EdmEntityType entityType = edmEntitySet.getEntityType();

	ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).suffix(ContextURL.Suffix.ENTITY).build();
 	// expand and select currently not supported
	EntitySerializerOptions options = EntitySerializerOptions.with().contextURL(contextUrl).build();

	ODataSerializer serializer = this.odata.createSerializer(responseFormat);
	SerializerResult serializerResult = serializer.entity(serviceMetadata, entityType, entity, options);
	InputStream entityStream = serializerResult.getContent();

	//4. configure the response object
	response.setContent(entityStream);
	response.setStatusCode(HttpStatusCode.OK.getStatusCode());
	response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType responseFormat) throws ODataApplicationException, SerializerException {

		// 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
		List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
		UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); // in our example, the first segment is the EntitySet
		EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

		// 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
		EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);

		// 3rd: create a serializer based on the requested format (json)
		ODataSerializer serializer = odata.createSerializer(responseFormat);

		// and serialize the content: transform from the EntitySet object to InputStream
		EdmEntityType edmEntityType = edmEntitySet.getEntityType();
		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

		final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
		EntityCollectionSerializerOptions opts =
				EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
		SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType, entityCollection, opts);
		InputStream serializedContent = serializerResult.getContent();

		// 4th: configure the response object: set the body, headers and status code
		response.setContent(serializedContent);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readEntity(ODataRequest request, ODataResponse response, UriInfo uriInfo, ContentType responseFormat)
    throws ODataApplicationException, SerializerException {

  // 1. retrieve the Entity Type
  List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  // Note: only in our example we can assume that the first segment is the EntitySet
  UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0);
  EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

  // 2. retrieve the data from backend
  List<UriParameter> keyPredicates = uriResourceEntitySet.getKeyPredicates();
  Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);

  // 3. serialize
  EdmEntityType entityType = edmEntitySet.getEntityType();

  ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).suffix(ContextURL.Suffix.ENTITY).build();
  // expand and select currently not supported
  EntitySerializerOptions options = EntitySerializerOptions.with().contextURL(contextUrl).build();

  ODataSerializer serializer = this.odata.createSerializer(responseFormat);
  SerializerResult serializerResult = serializer.entity(serviceMetadata, entityType, entity, options);
  InputStream entityStream = serializerResult.getContent();

  // 4. configure the response object
  response.setContent(entityStream);
  response.setStatusCode(HttpStatusCode.OK.getStatusCode());
  response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
@Override
public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo,
    ContentType responseFormat) throws ODataApplicationException, SerializerException {

  // 1st: retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
  List<UriResource> resourcePaths = uriInfo.getUriResourceParts();

  // in our example, the first segment is the EntitySet
  UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0);
  EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

  // 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
  EntityCollection entityCollection = getData(edmEntitySet);
  EntityCollection modifiedEntityCollection = new EntityCollection();
  List<Entity> modifiedEntityList = new ArrayList<Entity>();

  modifiedEntityList.addAll(entityCollection.getEntities());

  // // 3rd: Apply system query option
  // // The system query options have to be applied in a defined order
  // // 3.1.) $filter
  // modifiedEntityList = applyFilterQueryOption(modifiedEntityList, uriInfo.getFilterOption());
  //
  // // 3.2.) $orderby
  // modifiedEntityList = applyOrderQueryOption(modifiedEntityList, uriInfo.getOrderByOption());
  //
  // // 3.3.) $count
  // modifiedEntityList = applyCountQueryOption(modifiedEntityCollection, modifiedEntityList,
  // uriInfo.getCountOption());
  //
  // // 3.4.) $skip
  // modifiedEntityList = applySkipQueryOption(modifiedEntityList, uriInfo.getSkipOption());
  //
  // // 3.5.) $top
  // modifiedEntityList = applyTopQueryOption(modifiedEntityList, uriInfo.getTopOption());
  //
  // // 3.6.) Server driven paging (not part of this tutorial)
  // // 3.7.) $expand
  // modifiedEntityList = applyExpandQueryOption(modifiedEntityList, edmEntitySet,
  // uriInfo.getExpandOption());
  // 3.8.) $select
  SelectOption selectOption = uriInfo.getSelectOption();

  // Set the (may) modified entityList to the new entity collection
  modifiedEntityCollection.getEntities().addAll(modifiedEntityList);

  // 4th: create a serializer based on the requested format (json)
  ODataSerializer serializer = odata.createSerializer(responseFormat);

  // we need the property names of the $select, in order to build the context URL
  EdmEntityType edmEntityType = edmEntitySet.getEntityType();
  String selectList = odata.createUriHelper().buildContextURLSelectList(edmEntityType,
      uriInfo.getExpandOption(), selectOption);
  ContextURL contextUrl =
      ContextURL.with().entitySet(edmEntitySet).selectList(selectList).build();

  // adding the selectOption to the serializerOpts will actually tell the lib to do the job
  final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
  EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions.with()
      .contextURL(contextUrl).count(uriInfo.getCountOption()).select(selectOption)
      .expand(uriInfo.getExpandOption()).id(id).build();

  // and serialize the content: transform from the EntitySet object to InputStream
  SerializerResult serializerResult =
      serializer.entityCollection(serviceMetadata, edmEntityType, modifiedEntityCollection, opts);
  InputStream serializedContent = serializerResult.getContent();

  // 5th: configure the response object: set the body, headers and status code
  response.setContent(serializedContent);
  response.setStatusCode(HttpStatusCode.OK.getStatusCode());
  response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readPrimitive(ODataRequest request, ODataResponse response,
							UriInfo uriInfo, ContentType responseFormat)
							throws ODataApplicationException, SerializerException {

	// 1. Retrieve info from URI
	// 1.1. retrieve the info about the requested entity set
	List<UriResource> resourceParts = uriInfo.getUriResourceParts();
	// Note: only in our example we can rely that the first segment is the EntitySet
	UriResourceEntitySet uriEntityset = (UriResourceEntitySet) resourceParts.get(0);
	EdmEntitySet edmEntitySet = uriEntityset.getEntitySet();
	// the key for the entity
	List<UriParameter> keyPredicates = uriEntityset.getKeyPredicates();

	// 1.2. retrieve the requested (Edm) property
	// the last segment is the Property
	UriResourceProperty uriProperty = (UriResourceProperty)resourceParts.get(resourceParts.size() -1); 
	EdmProperty edmProperty = uriProperty.getProperty();
	String edmPropertyName = edmProperty.getName();
	// in our example, we know we have only primitive types in our model
	EdmPrimitiveType edmPropertyType = (EdmPrimitiveType) edmProperty.getType();


	// 2. retrieve data from backend
	// 2.1. retrieve the entity data, for which the property has to be read
	Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);
	if (entity == null) { // Bad request
		throw new ODataApplicationException("Entity not found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
	}

	// 2.2. retrieve the property data from the entity
	Property property = entity.getProperty(edmPropertyName);
	if (property == null) {
		throw new ODataApplicationException("Property not found", HttpStatusCode.NOT_FOUND.getStatusCode(), 
		                                    Locale.ENGLISH);
	}

	// 3. serialize
	Object value = property.getValue();
	if (value != null) {
		// 3.1. configure the serializer
		ODataSerializer serializer = odata.createSerializer(responseFormat);

		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName).build();
		PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
		// 3.2. serialize
		SerializerResult serializerResult = serializer.primitive(serviceMetadata, edmPropertyType, property, options);
		InputStream propertyStream = serializerResult.getContent();

		//4. configure the response object
		response.setContent(propertyStream);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	} else {
		// in case there's no value for the property, we can skip the serialization
		response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
	}
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, 
    ContentType responseFormat) throws ODataApplicationException, SerializerException {

	// 1st: retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// in our example, the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); 
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	// 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
	EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);
	
	// 3rd: Check if filter system query option is provided and apply the expression if necessary
	FilterOption filterOption = uriInfo.getFilterOption();
	if(filterOption != null) {
		// Apply $filter system query option
		try {
		      List<Entity> entityList = entityCollection.getEntities();
		      Iterator<Entity> entityIterator = entityList.iterator();
		      
		      // Evaluate the expression for each entity
		      // If the expression is evaluated to "true", keep the entity otherwise remove it from the entityList
		      while (entityIterator.hasNext()) {
		    	  // To evaluate the the expression, create an instance of the Filter Expression Visitor and pass
		    	  // the current entity to the constructor
		    	  Entity currentEntity = entityIterator.next();
		    	  Expression filterExpression = filterOption.getExpression();
		    	  FilterExpressionVisitor expressionVisitor = new FilterExpressionVisitor(currentEntity);
		    	  
		    	  // Start evaluating the expression
		    	  Object visitorResult = filterExpression.accept(expressionVisitor);
		    	  
		    	  // The result of the filter expression must be of type Edm.Boolean
		    	  if(visitorResult instanceof Boolean) {
		    		  if(!Boolean.TRUE.equals(visitorResult)) {
		    		    // The expression evaluated to false (or null), so we have to remove the currentEntity from entityList
		    		    entityIterator.remove();
		    		  }
		    	  } else {
		    		  throw new ODataApplicationException("A filter expression must evaulate to type Edm.Boolean", 
		    		      HttpStatusCode.BAD_REQUEST.getStatusCode(), Locale.ENGLISH);
		    	  }
		      }

		    } catch (ExpressionVisitException e) {
		      throw new ODataApplicationException("Exception in filter evaluation",
		          HttpStatusCode.INTERNAL_SERVER_ERROR.getStatusCode(), Locale.ENGLISH);
		    }
	}
	
	// 4th: create a serializer based on the requested format (json)
	ODataSerializer serializer = odata.createSerializer(responseFormat);

	// and serialize the content: transform from the EntitySet object to InputStream
	EdmEntityType edmEntityType = edmEntitySet.getEntityType();
	ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

	final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
	EntityCollectionSerializerOptions opts = EntityCollectionSerializerOptions.with()
			.contextURL(contextUrl).id(id).build();
	SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType, entityCollection,
			opts);

	InputStream serializedContent = serializerResult.getContent();

	// 5th: configure the response object: set the body, headers and status code
	response.setContent(serializedContent);
	response.setStatusCode(HttpStatusCode.OK.getStatusCode());
	response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readPrimitive(ODataRequest request, ODataResponse response,
							UriInfo uriInfo, ContentType responseFormat)
							throws ODataApplicationException, SerializerException {

	// 1. Retrieve info from URI
	// 1.1. retrieve the info about the requested entity set
	List<UriResource> resourceParts = uriInfo.getUriResourceParts();
	// Note: only in our example we can rely that the first segment is the EntitySet
	UriResourceEntitySet uriEntityset = (UriResourceEntitySet) resourceParts.get(0);
	EdmEntitySet edmEntitySet = uriEntityset.getEntitySet();
	// the key for the entity
	List<UriParameter> keyPredicates = uriEntityset.getKeyPredicates();

	// 1.2. retrieve the requested (Edm) property
	UriResourceProperty uriProperty = (UriResourceProperty)resourceParts.get(resourceParts.size() -1); // the last segment is the Property
	EdmProperty edmProperty = uriProperty.getProperty();
	String edmPropertyName = edmProperty.getName();
	// in our example, we know we have only primitive types in our model
	EdmPrimitiveType edmPropertyType = (EdmPrimitiveType) edmProperty.getType();


	// 2. retrieve data from backend
	// 2.1. retrieve the entity data, for which the property has to be read
	Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);
	if (entity == null) { // Bad request
		throw new ODataApplicationException("Entity not found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
	}

	// 2.2. retrieve the property data from the entity
	Property property = entity.getProperty(edmPropertyName);
	if (property == null) {
		throw new ODataApplicationException("Property not found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
	}

	// 3. serialize
	Object value = property.getValue();
	if (value != null) {
		// 3.1. configure the serializer
		ODataSerializer serializer = odata.createSerializer(responseFormat);

		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName).build();
		PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
		// 3.2. serialize
		SerializerResult serializerResult = serializer.primitive(serviceMetadata, edmPropertyType, property, options);
		InputStream propertyStream = serializerResult.getContent();

		//4. configure the response object
		response.setContent(propertyStream);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	} else {
		// in case there's no value for the property, we can skip the serialization
		response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
	}
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readPrimitive(ODataRequest request, ODataResponse response,UriInfo uriInfo, ContentType responseFormat) 
    throws ODataApplicationException, SerializerException {

	// 1. Retrieve info from URI
	// 1.1. retrieve the info about the requested entity set
	List<UriResource> resourceParts = uriInfo.getUriResourceParts();
	// Note: only in our example we can rely that the first segment is the EntitySet
	UriResourceEntitySet uriEntityset = (UriResourceEntitySet) resourceParts.get(0);
	EdmEntitySet edmEntitySet = uriEntityset.getEntitySet();
	// the key for the entity
	List<UriParameter> keyPredicates = uriEntityset.getKeyPredicates();

	// 1.2. retrieve the requested (Edm) property
	// the last segment is the Property
	UriResourceProperty uriProperty = (UriResourceProperty)resourceParts.get(resourceParts.size() -1); 
	EdmProperty edmProperty = uriProperty.getProperty();
	String edmPropertyName = edmProperty.getName();
	// in our example, we know we have only primitive types in our model
	EdmPrimitiveType edmPropertyType = (EdmPrimitiveType) edmProperty.getType();


	// 2. retrieve data from backend
	// 2.1. retrieve the entity data, for which the property has to be read
	Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);
	if (entity == null) { // Bad request
		throw new ODataApplicationException("Entity not found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
	}

	// 2.2. retrieve the property data from the entity
	Property property = entity.getProperty(edmPropertyName);
	if (property == null) {
		throw new ODataApplicationException("Property not found", HttpStatusCode.NOT_FOUND.getStatusCode(), 
		                                    Locale.ENGLISH);
	}

	// 3. serialize
	Object value = property.getValue();
	if (value != null) {
		// 3.1. configure the serializer
		ODataSerializer serializer = odata.createSerializer(responseFormat);

		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName).build();
		PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
		// 3.2. serialize
		SerializerResult serializerResult = serializer.primitive(serviceMetadata, edmPropertyType, property, options);
		InputStream propertyStream = serializerResult.getContent();

		//4. configure the response object
		response.setContent(propertyStream);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	} else {
		// in case there's no value for the property, we can skip the serialization
		response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
	}
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo, 
    ContentType responseFormat) throws ODataApplicationException, SerializerException {

	// 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
	List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
	// in our example, the first segment is the EntitySet
	UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0); 
	EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

	// 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
	EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);
	List<Entity> entityList = entityCollection.getEntities();
	
	// 3rd apply $orderby
	OrderByOption orderByOption = uriInfo.getOrderByOption();
	if (orderByOption != null) {
		List<OrderByItem> orderItemList = orderByOption.getOrders();
		final OrderByItem orderByItem = orderItemList.get(0); // in our example we support only one
		Expression expression = orderByItem.getExpression();
		if(expression instanceof Member){
			UriInfoResource resourcePath = ((Member)expression).getResourcePath();
			UriResource uriResource = resourcePath.getUriResourceParts().get(0);
			if (uriResource instanceof UriResourcePrimitiveProperty) {
				EdmProperty edmProperty = ((UriResourcePrimitiveProperty)uriResource).getProperty();
				final String sortPropertyName = edmProperty.getName();

				// do the sorting for the list of entities  
				Collections.sort(entityList, new Comparator<Entity>() {

					// we delegate the sorting to the native sorter of Integer and String
					public int compare(Entity entity1, Entity entity2) {
						int compareResult = 0;

						if(sortPropertyName.equals("ID")){
							Integer integer1 = (Integer) entity1.getProperty(sortPropertyName).getValue();
							Integer integer2 = (Integer) entity2.getProperty(sortPropertyName).getValue();
							
							compareResult = integer1.compareTo(integer2);
						}else{
							String propertyValue1 = (String) entity1.getProperty(sortPropertyName).getValue();
							String propertyValue2 = (String) entity2.getProperty(sortPropertyName).getValue();
							
							compareResult = propertyValue1.compareTo(propertyValue2);
						}

						// if 'desc' is specified in the URI, change the order of the list 
						if(orderByItem.isDescending()){
							return - compareResult; // just convert the result to negative value to change the order
						}
						
						return compareResult;
					}
				});
			}
		}
	}
	
	
	// 4th: create a serializer based on the requested format (json)
	ODataSerializer serializer = odata.createSerializer(responseFormat);

	// and serialize the content: transform from the EntitySet object to InputStream
	EdmEntityType edmEntityType = edmEntitySet.getEntityType();
	ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

	final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
	EntityCollectionSerializerOptions opts =
			EntityCollectionSerializerOptions.with().id(id).contextURL(contextUrl).build();
   SerializerResult serializerResult = serializer.entityCollection(serviceMetadata, edmEntityType, 
                                                                   entityCollection, opts);
	InputStream serializedContent = serializerResult.getContent();

	// 5th: configure the response object: set the body, headers and status code
	response.setContent(serializedContent);
	response.setStatusCode(HttpStatusCode.OK.getStatusCode());
	response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readPrimitive(ODataRequest request, ODataResponse response,
    UriInfo uriInfo, ContentType responseFormat)
    throws ODataApplicationException, SerializerException {

  // 1. Retrieve info from URI
  // 1.1. retrieve the info about the requested entity set
  List<UriResource> resourceParts = uriInfo.getUriResourceParts();
  // Note: only in our example we can rely that the first segment is the EntitySet
  UriResourceEntitySet uriEntityset = (UriResourceEntitySet) resourceParts.get(0);
  EdmEntitySet edmEntitySet = uriEntityset.getEntitySet();
  // the key for the entity
  List<UriParameter> keyPredicates = uriEntityset.getKeyPredicates();

  // 1.2. retrieve the requested (Edm) property
  // the last segment is the Property
  UriResourceProperty uriProperty = (UriResourceProperty) resourceParts.get(resourceParts.size() - 1);
  EdmProperty edmProperty = uriProperty.getProperty();
  String edmPropertyName = edmProperty.getName();
  // in our example, we know we have only primitive types in our model
  EdmPrimitiveType edmPropertyType = (EdmPrimitiveType) edmProperty.getType();

  // 2. retrieve data from backend
  // 2.1. retrieve the entity data, for which the property has to be read
  Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);
  if (entity == null) { // Bad request
    throw new ODataApplicationException("Entity not found",
        HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
  }

  // 2.2. retrieve the property data from the entity
  Property property = entity.getProperty(edmPropertyName);
  if (property == null) {
    throw new ODataApplicationException("Property not found",
        HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ENGLISH);
  }

  // 3. serialize
  Object value = property.getValue();
  if (value != null) {
    // 3.1. configure the serializer
    ODataSerializer serializer = odata.createSerializer(responseFormat);

    ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName).build();
    PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
    // 3.2. serialize
    SerializerResult serializerResult = serializer.primitive(serviceMetadata, edmPropertyType, property, options);
    InputStream propertyStream = serializerResult.getContent();

    // 4. configure the response object
    response.setContent(propertyStream);
    response.setStatusCode(HttpStatusCode.OK.getStatusCode());
    response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
  } else {
    // in case there's no value for the property, we can skip the serialization
    response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
  }
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readPrimitive(ODataRequest request, ODataResponse response,
							UriInfo uriInfo, ContentType responseFormat)
							throws ODataApplicationException, SerializerException {

	// 1. Retrieve info from URI
	// 1.1. retrieve the info about the requested entity set
	List<UriResource> resourceParts = uriInfo.getUriResourceParts();
	// Note: only in our example we can rely that the first segment is the EntitySet
	UriResourceEntitySet uriEntityset = (UriResourceEntitySet) resourceParts.get(0);
	EdmEntitySet edmEntitySet = uriEntityset.getEntitySet();
	// the key for the entity
	List<UriParameter> keyPredicates = uriEntityset.getKeyPredicates();

	// 1.2. retrieve the requested (Edm) property
	// the last segment is the Property
	UriResourceProperty uriProperty = (UriResourceProperty)resourceParts.get(resourceParts.size() -1);
	EdmProperty edmProperty = uriProperty.getProperty();
	String edmPropertyName = edmProperty.getName();
	// in our example, we know we have only primitive types in our model
	EdmPrimitiveType edmPropertyType = (EdmPrimitiveType) edmProperty.getType();


	// 2. retrieve data from backend
	// 2.1. retrieve the entity data, for which the property has to be read
	Entity entity = storage.readEntityData(edmEntitySet, keyPredicates);
	if (entity == null) { // Bad request
		throw new ODataApplicationException("Entity not found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ROOT);
	}

	// 2.2. retrieve the property data from the entity
	Property property = entity.getProperty(edmPropertyName);
	if (property == null) {
		throw new ODataApplicationException("Property not found", HttpStatusCode.NOT_FOUND.getStatusCode(), Locale.ROOT);
	}

	// 3. serialize
	Object value = property.getValue();
	if (value != null) {
		// 3.1. configure the serializer
		ODataSerializer serializer = odata.createSerializer(responseFormat);

		ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).navOrPropertyPath(edmPropertyName).build();
		PrimitiveSerializerOptions options = PrimitiveSerializerOptions.with().contextURL(contextUrl).build();
		// 3.2. serialize
		SerializerResult serializerResult = serializer.primitive(serviceMetadata, edmPropertyType, property, options);
		InputStream propertyStream = serializerResult.getContent();

		//4. configure the response object
		response.setContent(propertyStream);
		response.setStatusCode(HttpStatusCode.OK.getStatusCode());
		response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
	} else {
		// in case there's no value for the property, we can skip the serialization
		response.setStatusCode(HttpStatusCode.NO_CONTENT.getStatusCode());
	}
}
 

import org.apache.olingo.server.api.serializer.SerializerResult; //导入方法依赖的package包/类
public void readEntityCollection(ODataRequest request, ODataResponse response, UriInfo uriInfo,
    ContentType responseFormat) throws ODataApplicationException, SerializerException {

  // 1st retrieve the requested EntitySet from the uriInfo (representation of the parsed URI)
  List<UriResource> resourcePaths = uriInfo.getUriResourceParts();
  // in our example, the first segment is the EntitySet
  UriResourceEntitySet uriResourceEntitySet = (UriResourceEntitySet) resourcePaths.get(0);
  EdmEntitySet edmEntitySet = uriResourceEntitySet.getEntitySet();

  // 2nd: fetch the data from backend for this requested EntitySetName and deliver as EntitySet
  EntityCollection entityCollection = storage.readEntitySetData(edmEntitySet);

  // 3rd: apply System Query Options
  // modify the result set according to the query options, specified by the end user
  List<Entity> entityList = entityCollection.getEntities();
  EntityCollection returnEntityCollection = new EntityCollection();

  // handle $count: always return the original number of entities, without considering $top and $skip
  CountOption countOption = uriInfo.getCountOption();
  if (countOption != null) {
    boolean isCount = countOption.getValue();
    if (isCount) {
      returnEntityCollection.setCount(entityList.size());
    }
  }
  
  // handle $skip
  SkipOption skipOption = uriInfo.getSkipOption();
  if (skipOption != null) {
    int skipNumber = skipOption.getValue();
    if (skipNumber >= 0) {
      if(skipNumber <= entityList.size()) {
        entityList = entityList.subList(skipNumber, entityList.size());
      } else {
        // The client skipped all entities
        entityList.clear();
      }
    } else {
      throw new ODataApplicationException("Invalid value for $skip", HttpStatusCode.BAD_REQUEST.getStatusCode(),
          Locale.ROOT);
    }
  }
  
  // handle $top
  TopOption topOption = uriInfo.getTopOption();
  if (topOption != null) {
    int topNumber = topOption.getValue();
    if (topNumber >= 0) {
      if(topNumber <= entityList.size()) {
        entityList = entityList.subList(0, topNumber);
      }  // else the client has requested more entities than available => return what we have
    } else {
      throw new ODataApplicationException("Invalid value for $top", HttpStatusCode.BAD_REQUEST.getStatusCode(),
          Locale.ROOT);
    }
  }

  // after applying the system query options, create the EntityCollection based on the reduced list
  for (Entity entity : entityList) {
    returnEntityCollection.getEntities().add(entity);
  }

  // 4th: create a serializer based on the requested format (json)
  ODataSerializer serializer = odata.createSerializer(responseFormat);

  // and serialize the content: transform from the EntitySet object to InputStream
  EdmEntityType edmEntityType = edmEntitySet.getEntityType();
  ContextURL contextUrl = ContextURL.with().entitySet(edmEntitySet).build();

  final String id = request.getRawBaseUri() + "/" + edmEntitySet.getName();
  EntityCollectionSerializerOptions opts =
      EntityCollectionSerializerOptions.with().contextURL(contextUrl).id(id).count(countOption).build();
  SerializerResult serializerResult =
      serializer.entityCollection(serviceMetadata, edmEntityType, returnEntityCollection, opts);
  InputStream serializedContent = serializerResult.getContent();

  // 5th: configure the response object: set the body, headers and status code
  response.setContent(serializedContent);
  response.setStatusCode(HttpStatusCode.OK.getStatusCode());
  response.setHeader(HttpHeader.CONTENT_TYPE, responseFormat.toContentTypeString());
}