组件注册
用@Bean来注册
搭建好maven web工程
pom加入spring-context,spring-core等核心依赖
创建实例类com.hjj.bean.Person, 生成getter,setter方法
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public class Person { private String name; private int age; } |
创建com.hjj.config.MainConfig
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@Configuration //告诉spring是一个配置类 public class MainConfig { // 给容器中注册一个Bean,类行为返回值的类型,id默认是用方法名作为id @Bean ( "mikePerson" ) public Person person(){ return new Person( "mike" , 20 ); } } |
主测试类
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public class MainTest { public static void main(String[] args) { AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig. class ); Person bean = applicationContext.getBean(Person. class ); System.out.println(bean); String[] beanNamesForType = applicationContext.getBeanNamesForType(Person. class ); for (String type : beanNamesForType) { System.out.println(type); //配置类中的方法名,注意:通过修改配置类的@bean value也可以修改 } } } |
@ComponentScan包扫描
配置类中MainConfig.java
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@Configuration //告诉spring是一个配置类 @ComponentScan ( "com.hjj" ) // 扫描包的路径 public class MainConfig { // 给容器中注册一个Bean,类行为返回值的类型,id默认是用方法名作为id @Bean ( "mikePerson" ) public Person person(){ return new Person( "mike" , 20 ); } } |
新建测试的com.hjj.controller,service,dao
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@Controller public class BookController { } @Repository public class BookDao { } @Service public class BookService { } |
单元测试
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@Test public void test01(){ AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig. class ); String[] beanDefinitionNames = applicationContext.getBeanDefinitionNames(); //获取所有组件 for (String beanDefinitionName : beanDefinitionNames) { System.out.println(beanDefinitionName); } } |
ComponentScan字段,有includeFilter(),和excludeFilter() 只包含或排除某些组件
@ComponentScan(value = "com.hjj",excludeFilters={@Filter(type=FilterType.ANNOTATION,classes={Controller.class,Service.class})})
@ComponentScan(value = "com.hjj",includeFilters={@Filter(type=FilterType.ANNOTATION,classes={Controller.class,Service.class})},userDefaultFilters=false)// excludeFilter源码
ComponentScan.Filter[] excludeFilters() default {};
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// ComponentScan.Filter源码 @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 {}; } |
@ComponentScan被@Repeatable(ComponentScans.class),可以重复写,用来写不同的执行策略。
@ComponentScans 里面可以放ComponentScan类型的值
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@Retention (RetentionPolicy.RUNTIME) @Target ({ElementType.TYPE}) @Documented public @interface ComponentScans { ComponentScan[] value(); } |
FilterType
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public enum FilterType { ANNOTATION, // 按注解扫描 ASSIGNABLE_TYPE, // 按给定的类型 ASPECTJ, // 可以用aspectJ表达式 REGEX, // 正则表达式 CUSTOM; // 自定义规则 private FilterType() { } } |
ASSIGNABLE_TYPE
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@ComponentScan (value = "com.hjj" , includeFilters ={ @ComponentScan .Filter(type=FilterType.ASSIGNABLE_TYPE,classes = {BookService. class })}) // config配置如上注解后 bookservice,可以被发现 @Test public void demoTest1(){ AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig. class ); String[] beanDefinitionNames = applicationContext.getBeanDefinitionNames(); for (String beanDefinitionName : beanDefinitionNames) { System.out.println(beanDefinitionName); } } |
Custom 可以自定义配置或写业务扫描类的信息,match返回true则是加到组件
1.复写TypeFilter的match方法
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public class MyTypeFilter implements TypeFilter { /** * * @param metadataReader 读取到的当前正在扫描的类的信息 * @param metadataReaderFactory 可以获取到其他任何类信息 * @return * @throws IOException */ @Override public boolean match(MetadataReader metadataReader, MetadataReaderFactory metadataReaderFactory) throws IOException { // 获取当前类注解的信息 AnnotationMetadata annotationMetadata = metadataReader.getAnnotationMetadata(); // 获取当前正在扫描类的信息 ClassMetadata classMetadata = metadataReader.getClassMetadata(); // 获取当前类资源(类的路径等) Resource resource = metadataReader.getResource(); String className = classMetadata.getClassName(); System.out.println( "className:" + className); return false ; } } |
2. 加上注解
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@Configuration //告诉spring是一个配置类 @ComponentScan (value = "com.hjj" , includeFilters ={ @ComponentScan .Filter(type=FilterType.CUSTOM,classes = {MyTypeFilter. class })}, useDefaultFilter= false ) public class MainConfig { } @Test public void test01(){ AnnotationConfigApplicationContext applicationContext = new AnnotationConfigApplicationContext(MainConfig. class ); String[] beanDefinitionNames = applicationContext.getBeanDefinitionNames(); for (String beanDefinitionName : beanDefinitionNames) { System.out.println(beanDefinitionName); } } |
结果
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className:com.hjj. test .IOCTest className:com.hjj.MainTest className:com.hjj.bean.Person className:com.hjj.config.MyTypeFilter className:com.hjj.demo.DemoTest className:com.hjj.demo.Employee className:com.hjj.demo.Manager org.springframework.context.annotation.internalConfigurationAnnotationProcessor org.springframework.context.annotation.internalAutowiredAnnotationProcessor org.springframework.context.annotation.internalCommonAnnotationProcessor org.springframework.context.event.internalEventListenerProcessor org.springframework.context.event.internalEventListenerFactory mainConfig |
以上就是本文的全部内容,希望对大家的学习有所帮助,也希望大家多多支持服务器之家。
原文链接:https://www.cnblogs.com/jimmyhe/p/13549493.html