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 * 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
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 *      https://www.apache.org/licenses/LICENSE-2.0
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 * Unless required by applicable law or agreed to in writing, software
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package org.springframework.web.bind.annotation;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.springframework.core.annotation.AliasFor;

Annotation which indicates that a method parameter should be bound to a web request header.

Supported for annotated handler methods in Spring MVC and Spring WebFlux.

If the method parameter is Map<String, String>, MultiValueMap<String, String>, or HttpHeaders then the map is populated with all header names and values.

Author:Juergen Hoeller, Sam Brannen
See Also:
Since:3.0
/** * Annotation which indicates that a method parameter should be bound to a web request header. * * <p>Supported for annotated handler methods in Spring MVC and Spring WebFlux. * * <p>If the method parameter is {@link java.util.Map Map&lt;String, String&gt;}, * {@link org.springframework.util.MultiValueMap MultiValueMap&lt;String, String&gt;}, * or {@link org.springframework.http.HttpHeaders HttpHeaders} then the map is * populated with all header names and values. * * @author Juergen Hoeller * @author Sam Brannen * @since 3.0 * @see RequestMapping * @see RequestParam * @see CookieValue */
@Target(ElementType.PARAMETER) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface RequestHeader {
Alias for name.
/** * Alias for {@link #name}. */
@AliasFor("name") String value() default "";
The name of the request header to bind to.
Since:4.2
/** * The name of the request header to bind to. * @since 4.2 */
@AliasFor("value") String name() default "";
Whether the header is required.

Defaults to true, leading to an exception being thrown if the header is missing in the request. Switch this to false if you prefer a null value if the header is not present in the request.

Alternatively, provide a defaultValue, which implicitly sets this flag to false.

/** * Whether the header is required. * <p>Defaults to {@code true}, leading to an exception being thrown * if the header is missing in the request. Switch this to * {@code false} if you prefer a {@code null} value if the header is * not present in the request. * <p>Alternatively, provide a {@link #defaultValue}, which implicitly * sets this flag to {@code false}. */
boolean required() default true;
The default value to use as a fallback.

Supplying a default value implicitly sets required to false.

/** * The default value to use as a fallback. * <p>Supplying a default value implicitly sets {@link #required} to * {@code false}. */
String defaultValue() default ValueConstants.DEFAULT_NONE; }