Java

简介

Reflections通过扫描classpath，索引元数据，并且允许在运行时查询这些元数据。
使用Reflections可以很轻松的获取以下元数据信息：

  • 获取某个类型的全部子类
  • 只要类型、构造器、方法，字段上带有特定注解，便能获取带有这个注解的全部信息（类型、构造器、方法，字段）
  • 获取所有能匹配某个正则表达式的资源
  • 获取所有带有特定签名的方法，包括参数，参数注解，返回类型
  • 获取所有方法的名字
  • 获取代码里所有字段、方法名、构造器的使用

    Maven依赖

    在pom.xml中添加reflections的依赖：
    1. <dependency>
    2.   <groupId>org.reflections</groupId>
    3.   <artifactId>reflections</artifactId>
    4.   <version>0.9.11</version>
    5. </dependency>
    1. // 实例化Reflections，并指定要扫描的包名
    2. Reflections reflections = new Reflections("my.project");
    3. // 获取某个类的所有子类
    4. Set<Class<? extends SomeType>> subTypes = reflections.getSubTypesOf(SomeType.class);
    5. // 获取包含某个注解的所有类
    6. Set<Class<?>> annotated = reflections.getTypesAnnotatedWith(SomeAnnotation.class);

    使用

    ```java //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”)) …);

  1. <a name="pbgSm"></a>
  2. ### 扫描子类
  3. ```java
  4. Set<Class<? extends Module>> modules = reflections.getSubTypesOf(com.google.inject.Module.class);

扫描注解

  1. //TypeAnnotationsScanner 
  2. Set<Class<?>> singletons = reflections.getTypesAnnotatedWith(javax.inject.Singleton.class);

扫描资源

  1. //ResourcesScanner
  2. Set<String> properties = reflections.getResources(Pattern.compile(".*\\.properties"));

扫描方法注解

  1. //MethodAnnotationsScanner
  2. Set<Method> resources = reflections.getMethodsAnnotatedWith(javax.ws.rs.Path.class);
  3. Set<Constructor> injectables = reflections.getConstructorsAnnotatedWith(javax.inject.Inject.class);

扫描字段注解

  1. //FieldAnnotationsScanner
  2. Set<Field> ids = reflections.getFieldsAnnotatedWith(javax.persistence.Id.class);

扫描方法参数

  1. //MethodParameterScanner
  2. Set<Method> someMethods = reflections.getMethodsMatchParams(long.class, int.class);
  3. Set<Method> voidMethods = reflections.getMethodsReturn(void.class);
  4. Set<Method> pathParamMethods = reflections.getMethodsWithAnyParamAnnotated(PathParam.class);

扫描方法参数名

  1. //MethodParameterNamesScanner
  2. List<String> parameterNames = reflections.getMethodParamNames(Method.class)

扫描方法调用情况

  1. //MemberUsageScanner
  2. Set<Member> usages = reflections.getMethodUsages(Method.class)

参考资料

https://github.com/ronmamo/reflections