Java tutorial
/* * 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 * * https://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 org.springframework.core.annotation.AliasFor; /** * Annotation which indicates that a method parameter should be bound to a URI template * variable. Supported for {@link RequestMapping} annotated handler methods. * * <p>If the method parameter is {@link java.util.Map Map<String, String>} * then the map is populated with all path variable names and values. * * @author Arjen Poutsma * @author Juergen Hoeller * @since 3.0 * @see RequestMapping * @see org.springframework.web.servlet.mvc.method.annotation.RequestMappingHandlerAdapter */ @Target(ElementType.PARAMETER) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface PathVariable { /** * Alias for {@link #name}. */ @AliasFor("name") String value() default ""; /** * The name of the path variable to bind to. * @since 4.3.3 */ @AliasFor("value") String name() default ""; /** * Whether the path variable is required. * <p>Defaults to {@code true}, leading to an exception being thrown if the path * variable is missing in the incoming request. Switch this to {@code false} if * you prefer a {@code null} or Java 8 {@code java.util.Optional} in this case. * e.g. on a {@code ModelAttribute} method which serves for different requests. * @since 4.3.3 */ boolean required() default true; }