org.springframework.web.bind.annotation.RequestParam Maven / Gradle / Ivy
/*
* 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.
*/
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 java.util.Map;
import org.springframework.core.annotation.AliasFor;
/**
* Annotation which indicates that a method parameter should be bound to a web
* request parameter.
*
* Supported for annotated handler methods in Spring MVC and Spring WebFlux
* as follows:
*
* - In Spring MVC, "request parameters" map to query parameters, form data,
* and parts in multipart requests. This is because the Servlet API combines
* query parameters and form data into a single map called "parameters", and
* that includes automatic parsing of the request body.
*
- In Spring WebFlux, "request parameters" map to query parameters only.
* To work with all 3, query, form data, and multipart data, you can use data
* binding to a command object annotated with {@link ModelAttribute}.
*
*
* If the method parameter type is {@link Map} and a request parameter name
* is specified, then the request parameter value is converted to a {@link Map}
* assuming an appropriate conversion strategy is available.
*
*
If the method parameter is {@link java.util.Map Map<String, String>} or
* {@link org.springframework.util.MultiValueMap MultiValueMap<String, String>}
* and a parameter name is not specified, then the map parameter is populated
* with all request parameter names and values.
*
* @author Arjen Poutsma
* @author Juergen Hoeller
* @author Sam Brannen
* @since 2.5
* @see RequestMapping
* @see RequestHeader
* @see CookieValue
*/
@Target(ElementType.PARAMETER)
@Retention(RetentionPolicy.RUNTIME)
@Documented
public @interface RequestParam {
/**
* Alias for {@link #name}.
*/
@AliasFor("name")
String value() default "";
/**
* The name of the request parameter to bind to.
* @since 4.2
*/
@AliasFor("value")
String name() default "";
/**
* Whether the parameter is required.
*
Defaults to {@code true}, leading to an exception being thrown
* if the parameter is missing in the request. Switch this to
* {@code false} if you prefer a {@code null} value if the parameter is
* not present in the request.
*
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 when the request parameter is
* not provided or has an empty value.
*
Supplying a default value implicitly sets {@link #required} to
* {@code false}.
*/
String defaultValue() default ValueConstants.DEFAULT_NONE;
}