/*
 * Copyright 2002-2018 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
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package org.springframework.web.method.annotation;

import java.util.Map;

import org.springframework.beans.factory.config.ConfigurableBeanFactory;
import org.springframework.core.MethodParameter;
import org.springframework.lang.Nullable;
import org.springframework.util.Assert;
import org.springframework.web.bind.MissingRequestHeaderException;
import org.springframework.web.bind.ServletRequestBindingException;
import org.springframework.web.bind.WebDataBinder;
import org.springframework.web.bind.annotation.RequestHeader;
import org.springframework.web.context.request.NativeWebRequest;

Resolves method arguments annotated with @RequestHeader except for Map arguments. See RequestHeaderMapMethodArgumentResolver for details on Map arguments annotated with @RequestHeader.

An @RequestHeader is a named value resolved from a request header. It has a required flag and a default value to fall back on when the request header does not exist.

A WebDataBinder is invoked to apply type conversion to resolved request header values that don't yet match the method parameter type.

Author:Arjen Poutsma, Rossen Stoyanchev
Since:3.1
/** * Resolves method arguments annotated with {@code @RequestHeader} except for * {@link Map} arguments. See {@link RequestHeaderMapMethodArgumentResolver} for * details on {@link Map} arguments annotated with {@code @RequestHeader}. * * <p>An {@code @RequestHeader} is a named value resolved from a request header. * It has a required flag and a default value to fall back on when the request * header does not exist. * * <p>A {@link WebDataBinder} is invoked to apply type conversion to resolved * request header values that don't yet match the method parameter type. * * @author Arjen Poutsma * @author Rossen Stoyanchev * @since 3.1 */
public class RequestHeaderMethodArgumentResolver extends AbstractNamedValueMethodArgumentResolver {
Create a new RequestHeaderMethodArgumentResolver instance.
Params:
  • beanFactory – a bean factory to use for resolving ${...} placeholder and #{...} SpEL expressions in default values; or null if default values are not expected to have expressions
/** * Create a new {@link RequestHeaderMethodArgumentResolver} instance. * @param beanFactory a bean factory to use for resolving ${...} * placeholder and #{...} SpEL expressions in default values; * or {@code null} if default values are not expected to have expressions */
public RequestHeaderMethodArgumentResolver(@Nullable ConfigurableBeanFactory beanFactory) { super(beanFactory); } @Override public boolean supportsParameter(MethodParameter parameter) { return (parameter.hasParameterAnnotation(RequestHeader.class) && !Map.class.isAssignableFrom(parameter.nestedIfOptional().getNestedParameterType())); } @Override protected NamedValueInfo createNamedValueInfo(MethodParameter parameter) { RequestHeader ann = parameter.getParameterAnnotation(RequestHeader.class); Assert.state(ann != null, "No RequestHeader annotation"); return new RequestHeaderNamedValueInfo(ann); } @Override @Nullable protected Object resolveName(String name, MethodParameter parameter, NativeWebRequest request) throws Exception { String[] headerValues = request.getHeaderValues(name); if (headerValues != null) { return (headerValues.length == 1 ? headerValues[0] : headerValues); } else { return null; } } @Override protected void handleMissingValue(String name, MethodParameter parameter) throws ServletRequestBindingException { throw new MissingRequestHeaderException(name, parameter); } private static final class RequestHeaderNamedValueInfo extends NamedValueInfo { private RequestHeaderNamedValueInfo(RequestHeader annotation) { super(annotation.name(), annotation.required(), annotation.defaultValue()); } } }