反射工具包Reflections的使用

Reflections 通过扫描 classpath，索引元数据，允许在运行时查询这些元数据，也可以保存收集项目中多个模块的元数据信息。

 

maven依赖包：

<dependency>
	<groupId>org.reflections</groupId>
	<artifactId>reflections</artifactId>
	<version>0.9.11</version>
</dependency>

 

public class ReflectionsTest {
	public static final String BASE_PACKAGE = "com.seasy";
	
	public static void main(String[] args) {
		//查找资源文件
		Set<String> properties = getResourceReflections(BASE_PACKAGE).getResources(Pattern.compile(".*\\.properties"));
		for(String s : properties){
			System.out.println(s);
		}

		//找出被指定注解类标注的所有接口、类
		Set<Class<?>> annotationSet = getFullReflections(BASE_PACKAGE).getTypesAnnotatedWith(Mapper.class);
		for(Class<?> clazz : annotationSet){
			System.out.println(clazz.getName());
			Mapper annotation = clazz.getAnnotation(Mapper.class);
			System.out.println(annotation.value());
		}
		
		//找出指定接口的所有子类
		Set<Class<?extends CountryMapper>> classes = getFullReflections(BASE_PACKAGE).getSubTypesOf(CountryMapper.class);
		for(Class<?> clazz : classes){
			System.out.println(clazz.getName());
		}
		
		//查找有某个注解类的方法
		Set<Method> methodSet = getFullReflections(BASE_PACKAGE).getMethodsAnnotatedWith(GetMapping.class);
		for(Method m : methodSet){
			System.out.println(m.getDeclaringClass().getName());
			System.out.println(m.getName());
		}
		
		//查找有某个注解类的字段
		Set<Field> fieldSet = getFullReflections(BASE_PACKAGE).getFieldsAnnotatedWith(Autowired.class);
		for(Field f : fieldSet){
			System.out.println(f.getName());
		}
	}
	
	private static Reflections getResourceReflections(String basePackage){
		ConfigurationBuilder builder = new ConfigurationBuilder();
		builder.addUrls(ClasspathHelper.forPackage(basePackage));
		builder.setScanners(new ResourcesScanner());
		
		Reflections reflections = new Reflections(builder);
		return reflections;
	}
	
	/**
	 * 如果没有配置scanner，默认使用SubTypesScanner和TypeAnnotationsScanner
	 * @param basePackage 包路径
	 */
	private static Reflections getFullReflections(String basePackage){
		ConfigurationBuilder builder = new ConfigurationBuilder();
		builder.addUrls(ClasspathHelper.forPackage(basePackage));
		builder.setScanners(new TypeAnnotationsScanner(), new SubTypesScanner(),
				new MethodAnnotationsScanner(), new FieldAnnotationsScanner());
		builder.filterInputsBy(new FilterBuilder().includePackage(basePackage));
		
		Reflections reflections = new Reflections(builder);
		return reflections;
	}
}