001/* 002 * Copyright 2002-2017 the original author or authors. 003 * 004 * Licensed under the Apache License, Version 2.0 (the "License"); 005 * you may not use this file except in compliance with the License. 006 * You may obtain a copy of the License at 007 * 008 * https://www.apache.org/licenses/LICENSE-2.0 009 * 010 * Unless required by applicable law or agreed to in writing, software 011 * distributed under the License is distributed on an "AS IS" BASIS, 012 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. 013 * See the License for the specific language governing permissions and 014 * limitations under the License. 015 */ 016 017package org.springframework.stereotype; 018 019import java.lang.annotation.Documented; 020import java.lang.annotation.ElementType; 021import java.lang.annotation.Retention; 022import java.lang.annotation.RetentionPolicy; 023import java.lang.annotation.Target; 024 025import org.springframework.core.annotation.AliasFor; 026 027/** 028 * Indicates that an annotated class is a "Controller" (e.g. a web controller). 029 * 030 * <p>This annotation serves as a specialization of {@link Component @Component}, 031 * allowing for implementation classes to be autodetected through classpath scanning. 032 * It is typically used in combination with annotated handler methods based on the 033 * {@link org.springframework.web.bind.annotation.RequestMapping} annotation. 034 * 035 * @author Arjen Poutsma 036 * @author Juergen Hoeller 037 * @since 2.5 038 * @see Component 039 * @see org.springframework.web.bind.annotation.RequestMapping 040 * @see org.springframework.context.annotation.ClassPathBeanDefinitionScanner 041 */ 042@Target({ElementType.TYPE}) 043@Retention(RetentionPolicy.RUNTIME) 044@Documented 045@Component 046public @interface Controller { 047 048 /** 049 * The value may indicate a suggestion for a logical component name, 050 * to be turned into a Spring bean in case of an autodetected component. 051 * @return the suggested component name, if any (or empty String otherwise) 052 */ 053 @AliasFor(annotation = Component.class) 054 String value() default ""; 055 056}