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Reflections 应用指南

引入
<dependency>
<groupId>org.reflections</groupId>
<artifactId>reflections</artifactId>
<version>0.9.11</version>
</dependency>
典型应用
Reflections reflections = new Reflections("my.project");
Set<Class<? extends SomeType>> subTypes = reflections.getSubTypesOf(SomeType.class);
Set<Class<?>> annotated = reflections.getTypesAnnotatedWith(SomeAnnotation.class);

使用

基本上,使用 Reflections 首先使用 urls 和 scanners 对其进行实例化
//scan urls that contain 'my.package', include inputs starting with 'my.package', use the default scanners
Reflections reflections = new Reflections("my.package");
//or using ConfigurationBuilder
new Reflections(new ConfigurationBuilder()
.setUrls(ClasspathHelper.forPackage("my.project.prefix"))
.setScanners(new SubTypesScanner(),
new TypeAnnotationsScanner().filterResultsBy(optionalFilter), ...),
.filterInputsBy(new FilterBuilder().includePackage("my.project.prefix"))
...);
然后,使用方便的查询方法
// 子类型扫描
Set<Class<? extends Module>> modules =
reflections.getSubTypesOf(com.google.inject.Module.class);
// 类型注解扫描
Set<Class<?>> singletons =
reflections.getTypesAnnotatedWith(javax.inject.Singleton.class);
// 资源扫描
Set<String> properties =
reflections.getResources(Pattern.compile(".*\\.properties"));
// 方法注解扫描
Set<Method> resources =
reflections.getMethodsAnnotatedWith(javax.ws.rs.Path.class);
Set<Constructor> injectables =
reflections.getConstructorsAnnotatedWith(javax.inject.Inject.class);
// 字段注解扫描
Set<Field> ids =
reflections.getFieldsAnnotatedWith(javax.persistence.Id.class);
// 方法参数扫描
Set<Method> someMethods =
reflections.getMethodsMatchParams(long.class, int.class);
Set<Method> voidMethods =
reflections.getMethodsReturn(void.class);
Set<Method> pathParamMethods =
reflections.getMethodsWithAnyParamAnnotated(PathParam.class);
// 方法参数名扫描
List<String> parameterNames =
reflections.getMethodParamNames(Method.class)
// 方法使用扫描
Set<Member> usages =
reflections.getMethodUsages(Method.class)
说明:
  • 如果未配置扫描程序,则将使用默认值 - SubTypesScanner 和 TypeAnnotationsScanner。
  • 还可以配置类加载器,它将用于从名称中解析运行时类。
  • Reflection 默认情况下会扩展超类型。 这解决了传输 URL 不被扫描的一些问题。

ReflectionUtils

import static org.reflections.ReflectionUtils.*;
Set<Method> getters = getAllMethods(someClass,
withModifier(Modifier.PUBLIC), withPrefix("get"), withParametersCount(0));
//or
Set<Method> listMethodsFromCollectionToBoolean =
getAllMethods(List.class,
withParametersAssignableTo(Collection.class), withReturnType(boolean.class));
Set<Field> fields = getAllFields(SomeClass.class, withAnnotation(annotation), withTypeAssignableTo(type));