Springboot项目实现将类从@ComponentScan中去除
发布时间：2021-11-07 15:59:25 所属栏目：教程 来源：互联网
导读：目录 将类从@ComponentScan中排除问题描述方案一方案二方案三方案四@ComponentScan 详解 将类从@ComponentScan中排除 问题描述 最近在学习SpringCloud的Ribbon，在使用 @RibbonClient(name = SPRINGCLOUD-P-DEPT, configuration = RibbonConfig.class) 为服
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目录 将类从@ComponentScan中排除问题描述方案一方案二方案三方案四@ComponentScan 详解 将类从@ComponentScan中排除 问题描述 最近在学习SpringCloud的Ribbon，在使用 @RibbonClient(name = "SPRINGCLOUD-P-DEPT", configuration = RibbonConfig.class) 为服务指定负载均衡策略的时候，根据Ribbon官方文档介绍，自定义的Ribbon配置类不允许被Springboot的**@ComponentScan**注解扫描到，所以需要将自定义的配置类RibbonConfig从在Springboot自动注入的范围内排除 方案一 我们都知道，Springboot的**@SpringBootApplication**会自动扫描本类所在包下的所有类和子类，所以只需要将RibbonConfig定义在Springboot启动类所在包外面即可 方案二 通过在启动类中添加 @ComponentScan(excludeFilters = @ComponentScan.Filter( type = FilterType.ASSIGNABLE_TYPE, classes = RibbonConfig.class)) 通过FilterType.ASSIGNABLE_TYPE来指定要排除的类 如果需要排除的类太多了这个就很麻烦 方案三 通过自定义注解实现 @ComponentScan(excludeFilters = @ComponentScan.Filter( type = FilterType.ANNOTATION, classes = ScanIgnore.class)) 与方案二不同的是，这里用的是FilterType.ANNOTATION 方案四 通过实现TypeFilter类来自定义过滤器 @ComponentScan(excludeFilters = { @Filter( type = FilterType.CUSTOM, classes = TypeExcludeFilter.class), @Filter( type = FilterType.CUSTOM, classes = AutoConfigurationExcludeFilter.class) }) 此处给出的就是**@SpringbootApplication中的实现方式，通过FilterType.CUSTOM**来根据自动一过滤器来排除bean 最后贴出枚举类FilterType： /* * Copyright 2002-2013 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.context.annotation; /** * Enumeration of the type filters that may be used in conjunction with * {@link ComponentScan @ComponentScan}. * * @author Mark Fisher * @author Juergen Hoeller * @author Chris Beams * @since 2.5 * @see ComponentScan * @see ComponentScan#includeFilters() * @see ComponentScan#excludeFilters() * @see org.springframework.core.type.filter.TypeFilter */ public enum FilterType { /** * Filter candidates marked with a given annotation. * @see org.springframework.core.type.filter.AnnotationTypeFilter */ ANNOTATION, /** * Filter candidates assignable to a given type. * @see org.springframework.core.type.filter.AssignableTypeFilter */ ASSIGNABLE_TYPE, /** * Filter candidates matching a given AspectJ type pattern expression. * @see org.springframework.core.type.filter.AspectJTypeFilter */ ASPECTJ, /** * Filter candidates matching a given regex pattern. * @see org.springframework.core.type.filter.RegexPatternTypeFilter */ REGEX, /** Filter candidates using a given custom * {@link org.springframework.core.type.filter.TypeFilter} implementation. */ CUSTOM } @ComponentScan 详解 @ComponentScan 的作用就是根据定义的扫描路径，把符合扫描规则的类装配到spring容器中，注解定义如下。 @Retention(RetentionPolicy.RUNTIME) @Target({ElementType.TYPE}) @Documented @Repeatable(ComponentScans.class) public @interface ComponentScan { @AliasFor("basePackages") String[] value() default {}; @AliasFor("value") String[] basePackages() default {}; Class<?>[] basePackageClasses() default {}; Class<? extends BeanNameGenerator> nameGenerator() default BeanNameGenerator.class; Class<? extends ScopeMetadataResolver> scopeResolver() default AnnotationScopeMetadataResolver.class; ScopedProxyMode scopedProxy() default ScopedProxyMode.DEFAULT; String resourcePattern() default "**/*.class"; boolean useDefaultFilters() default true; ComponentScan.Filter[] includeFilters() default {}; ComponentScan.Filter[] excludeFilters() default {}; boolean lazyInit() default false; @Retention(RetentionPolicy.RUNTIME) @Target({}) public @interface Filter { FilterType type() default FilterType.ANNOTATION; @AliasFor("classes") Class<?>[] value() default {}; @AliasFor("value") Class<?>[] classes() default {}; String[] pattern() default {}; } } basePackages与value: 用于指定包的路径，进行扫描 basePackageClasses: 用于指定某个类的包的路径进行扫描 nameGenerator: bean的名称的生成器 useDefaultFilters: 是否开启对@Component，@Repository，@Service，@Controller的类进行检测 includeFilters: 包含的过滤条件 FilterType.ANNOTATION：按照注解过滤 FilterType.ASSIGNABLE_TYPE：按照给定的类型 FilterType.ASPECTJ：使用ASPECTJ表达式 FilterType.REGEX：正则 FilterType.CUSTOM：自定义规则 excludeFilters: 排除的过滤条件，用法和includeFilters一样 我的工程结构如下，测试对controller和service的扫描，其中HelloController没有加@Controller等任何注解，就是一个普通类。 修改配置类如下：应用默认的过滤器，扫描service包： @Configuration @ComponentScan(value = "com.xhx.spring.service", useDefaultFilters = true ) public class MyConfig { } 系统注入了两个service进去 改成如下所示：HelloController所在的包的类也被扫描了进去 @Configuration @ComponentScan(value = "com.xhx.spring.service", useDefaultFilters = true, basePackageClasses = HelloController.class ) public class MyConfig { } 系统中会注入下面就给类 把默认的过滤器关掉，扫描带Controller注解的。 @Configuration @ComponentScan(value = "com.xhx.spring", useDefaultFilters = false, includeFilters = { @ComponentScan.Filter(type = FilterType.ANNOTATION,classes = {Controller.class}) } ) public class MyConfig { } 按照类的类型扫描，虽然HelloController没有加注解，但是被注入到了spring容器中 @Configuration @ComponentScan(value = "com.xhx.spring", useDefaultFilters = false, includeFilters = { @ComponentScan.Filter(type = FilterType.ASSIGNABLE_TYPE,classes = {HelloController.class}) } ) public class MyConfig { } 自定义扫描过滤器 package com.xhx.spring.componentscan.config; import org.springframework.core.type.classreading.MetadataReader; import org.springframework.core.type.classreading.MetadataReaderFactory; import org.springframework.core.type.filter.TypeFilter; import java.io.IOException; /** * xuhaixing * 2018/9/18 23:07 **/ public class MyTypeFilter implements TypeFilter { @Override public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException { String className = metadataReader.getClassMetadata().getClassName(); if(className.contains("Controller")){ return true; } return false; } } 修改配置类 @Configuration @ComponentScan(value = "com.xhx.spring", useDefaultFilters = false, includeFilters = { @ComponentScan.Filter(type = FilterType.CUSTOM,classes = {MyTypeFilter.class}) } ) public class MyConfig { } 输出结果： 输出spring容器中的bean的测试类：只过滤输出了名字中含有hello的类。 package com.xhx.spring.componentscan; import com.xhx.spring.componentscan.config.MyConfig; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.boot.test.context.SpringBootTest; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import org.springframework.test.context.junit4.SpringRunner; import java.util.Arrays; import java.util.List; import java.util.stream.Collectors; @RunWith(SpringRunner.class) @SpringBootTest public class ComponentScanApplicationTests { @Test public void testLoads() { AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MyConfig.class); List<String> hello = Arrays.stream(context.getBeanDefinitionNames()).collect(Collectors.toList()); hello.stream().filter(name->name.contains("hello")).peek(System.out::println).count(); } } （编辑：大连站长网） 【声明】本站内容均来自网络，其相关言论仅代表作者个人观点，不代表本站立场。若无意侵犯到您的权利，请及时与联系站长删除相关内容! |
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