> For the complete documentation index, see [llms.txt](https://hezhiqiang8909.gitbook.io/java/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://hezhiqiang8909.gitbook.io/java/docs/javalib/reflections.md).

# Reflections 应用指南

* [使用](https://hezhiqiang8909.gitbook.io/java/docs/javalib/pages/-LyNWIq5RN-z7sF_XQZ-#使用)
* [ReflectionUtils](/java/docs/javalib/reflections.md#reflectionutils)

引入

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

典型应用

```java
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

```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"))
     ...);
```

然后，使用方便的查询方法

```java
// 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

```java
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));
```


---

# Agent Instructions
This documentation is published with GitBook. GitBook is the documentation platform designed so that both humans and AI agents can read, navigate, and reason over technical content effectively. Learn more at gitbook.com.

## Querying This Documentation
If you need additional information that is not directly available in this page, you can query the documentation dynamically by asking a question.

Perform an HTTP GET request on the current page URL with the `ask` query parameter, and the optional `goal` query parameter:

```
GET https://hezhiqiang8909.gitbook.io/java/docs/javalib/reflections.md?ask=<question>&goal=<endgoal>
```

`ask` is the immediate question: it should be specific, self-contained, and written in natural language.
`goal` is optional and describes the broader end goal you are ultimately trying to accomplish on behalf of the user. GitBook uses it to tailor the answer towards what is most useful for that goal.

The response will contain a direct answer to the question and relevant excerpts and sources from the documentation.

Use this mechanism when the answer is not explicitly present in the current page, you need clarification or additional context, or you want to retrieve related documentation sections.