Reflections 具体先容
Reflections 经过扫描 classpath，索引元数据，允许在运转时查询这些元数据，也可以保存搜集项目中多个模块的元数据信息。
使用 Reflections 可以查询以下元数据信息：
1）取得某个典范的一切子典范
2）取得标志了某个注解的一切典范／成员变量，支持注解参数婚配。
3）使用正则表达式取得一切婚配的资源文件
4）取得一切特定署名（包含参数，参数注解，前往值）的办法
Reflections 依托 Google 的 Guava 库和 Javassist 库。
Maven 项目导入
<dependency>
<groupId>org.reflections</groupId>
<artifactId>reflections</artifactId>
<version>0.9.10</version>
</dependency>
通常用法：
Reflections reflections = new Reflections(“my.project”);
Set<Class<? extends SomeType>> subTypes = reflections.getSubTypesOf(SomeType.class);
Set<Class<?>> annotated = reflections.getTypesAnnotatedWith(SomeAnnotation.class);
Reflections 初始化代码。
//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”))
…);
以下是一些使用例子代码。
//SubTypesScanner
Set<Class<? extends Module>> modules =
reflections.getSubTypesOf(com.google.inject.Module.class);
//TypeAnnotationsScanner
Set<Class<?>> singletons =
reflections.getTypesAnnotatedWith(javax.inject.Singleton.class);
//ResourcesScanner
Set<String> properties =
reflections.getResources(Pattern.compile(“.*\\.properties”));
//MethodAnnotationsScanner
Set<Method> resources =
reflections.getMethodsAnnotatedWith(javax.ws.rs.Path.class);
Set<Constructor> injectables =
reflections.getConstructorsAnnotatedWith(javax.inject.Inject.class);
//FieldAnnotationsScanner
Set<Field> ids =
reflections.getFieldsAnnotatedWith(javax.persistence.Id.class);
//MethodParameterScanner
Set<Method> someMethods =
reflections.getMethodsMatchParams(long.class, int.class);
Set<Method> voidMethods =
reflections.getMethodsReturn(void.class);
Set<Method> pathParamMethods =
reflections.getMethodsWithAnyParamAnnotated(PathParam.class);
//MethodParameterNamesScanner
List<String> parameterNames =
reflections.getMethodParamNames(Method.class)
//MemberUsageScanner
Set<Member> usages =
reflections.getMethodUsages(Method.class)
