Spring 实现自定义注解

自定义注解

1. 创建一个自定义注解MyService2. 创建一个类实现BeanDefinitionRegistryPostProcessor接口3. 创建一个实体，添加注解@MyService4. 测试方法CustomAnno代码下载地址

1. 创建一个自定义注解MyService

package org.example.annotation; import java.lang.annotation.*; @Target({ElementType.TYPE}) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface MyService { String value() default ""; }

2. 创建一个类实现BeanDefinitionRegistryPostProcessor接口

package org.example.annotation; import org.springframework.beans.BeansException; import org.springframework.beans.factory.config.ConfigurableListableBeanFactory; import org.springframework.beans.factory.support.BeanDefinitionRegistry; import org.springframework.beans.factory.support.BeanDefinitionRegistryPostProcessor; import org.springframework.context.annotation.ClassPathBeanDefinitionScanner; import org.springframework.core.type.filter.AnnotationTypeFilter; import org.springframework.stereotype.Component; @Component public class AnnotationTest implements BeanDefinitionRegistryPostProcessor { @Override public void postProcessBeanDefinitionRegistry(BeanDefinitionRegistry registry) throws BeansException { // 1.创建扫描器 ClassPathBeanDefinitionScanner scanner = new ClassPathBeanDefinitionScanner(registry); // 2.设置要被扫描到的注解名称，加入要被扫描到的注解的集合IncludeFilter中 scanner.addIncludeFilter(new AnnotationTypeFilter(MyService.class)); // 3.设置扫描路径 scanner.scan("org.example"); } @Override public void postProcessBeanFactory(ConfigurableListableBeanFactory beanFactory) throws BeansException { } }

3. 创建一个实体，添加注解@MyService

package org.example.bean; import org.example.annotation.MyService; @MyService public class MyAnnotationClass { public String name = "MyAnnotationClassTest"; public String getName() { return name; } public void setName(String name) { this.name = name; } }

4. 测试方法CustomAnno

单元测试，如果要使用@Autowired注入时，就必须使用@RunWith注解和@ContextConfiguration注解

package org.example.test; import org.example.bean.MyAnnotationClass; import org.example.bean.Student; import org.example.beanDefinition.UserClass; import org.junit.Test; import org.junit.runner.RunWith; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.context.ApplicationContext; import org.springframework.context.annotation.AnnotationConfigApplicationContext; import org.springframework.context.support.ClassPathXmlApplicationContext; import org.springframework.test.context.ContextConfiguration; import org.springframework.test.context.junit4.SpringJUnit4ClassRunner; //如果要使用@Autowired注入时，就必须使用@RunWith注解和@ContextConfiguration注解 //让测试运行于Spring测试环境 @RunWith(SpringJUnit4ClassRunner.class) //Spring整合JUnit4测试时，使用注解引入配置文件 @ContextConfiguration(locations = {"classpath:spring.xml"}) public class MyTest { @Autowired MyAnnotationClass myAnnoClass; @Test public void CustomAnno() { System.out.println("CustomAnno--->" + myAnnoClass.getName()); } @Test public void test1() { AnnotationConfigApplicationContext appcationContext = new AnnotationConfigApplicationContext("org.example"); Student student = (Student)appcationContext.getBean("student"); System.out.println(student.getUsername()); } @Test public void test2() { //基于xml的方式加载spring的配置文件，启动spring容器 ClassPathXmlApplicationContext appcationContext = new ClassPathXmlApplicationContext("spring.xml"); Student student = (Student)appcationContext.getBean("student"); System.out.println(student.getUsername()); } @Test public void test3() { ApplicationContext applicationContext = new AnnotationConfigApplicationContext("org.example"); UserClass userClass = (UserClass)applicationContext.getBean("UserClass"); System.out.println("UserClass-->" + userClass.getUsername()); } } 查看打印

代码下载地址

https://gitee.com/fisher3652/spring.git