「工具」反射框架Reflections
作者:互联网
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:
<dependency>
<groupId>org.reflections</groupId>
<artifactId>reflections</artifactId>
<version>0.9.11</version>
</dependency>
API 使用
//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"))
...);
扫描子类
Set<Class<? extends Module>> modules =
reflections.getSubTypesOf(com.google.inject.Module.class);
扫描注解
//TypeAnnotationsScanner
Set<Class<?>> singletons =
reflections.getTypesAnnotatedWith(javax.inject.Singleton.class);
扫描资源
//ResourcesScanner
Set<String> properties =
reflections.getResources(Pattern.compile(".*\\.properties"));
扫描方法注解
//MethodAnnotationsScanner
Set<Method> resources =
reflections.getMethodsAnnotatedWith(javax.ws.rs.Path.class);
Set<Constructor> injectables =
reflections.getConstructorsAnnotatedWith(javax.inject.Inject.class);
扫描字段注解
//FieldAnnotationsScanner
Set<Field> ids =
reflections.getFieldsAnnotatedWith(javax.persistence.Id.class);
扫描方法参数
//MethodParameterScanner
Set<Method> someMethods =
reflections.getMethodsMatchParams(long.class, int.class);
Set<Method> voidMethods =
reflections.getMethodsReturn(void.class);
Set<Method> pathParamMethods =
reflections.getMethodsWithAnyParamAnnotated(PathParam.class);
扫描方法参数名
//MethodParameterNamesScanner
List<String> parameterNames =
reflections.getMethodParamNames(Method.class)
扫描方法调用情况
//MemberUsageScanner
Set<Member> usages =
reflections.getMethodUsages(Method.class)
总结
项目中使用
public class ReflectionTest {
public static void main(String[] args) {
// 扫包
Reflections reflections = new Reflections(new ConfigurationBuilder()
.forPackages("com.boothsun.reflections") // 指定路径URL
.addScanners(new SubTypesScanner()) // 添加子类扫描工具
.addScanners(new FieldAnnotationsScanner()) // 添加 属性注解扫描工具
.addScanners(new MethodAnnotationsScanner() ) // 添加 方法注解扫描工具
.addScanners(new MethodParameterScanner() ) // 添加方法参数扫描工具
);
// 反射出子类
Set<Class<? extends ISayHello>> set = reflections.getSubTypesOf( ISayHello.class ) ;
System.out.println("getSubTypesOf:" + set);
// 反射出带有指定注解的类
Set<Class<?>> ss = reflections.getTypesAnnotatedWith( MyAnnotation.class );
System.out.println("getTypesAnnotatedWith:" + ss);
// 获取带有特定注解对应的方法
Set<Method> methods = reflections.getMethodsAnnotatedWith( MyMethodAnnotation.class ) ;
System.out.println("getMethodsAnnotatedWith:" + methods);
// 获取带有特定注解对应的字段
Set<Field> fields = reflections.getFieldsAnnotatedWith( Autowired.class ) ;
System.out.println("getFieldsAnnotatedWith:" + fields);
// 获取特定参数对应的方法
Set<Method> someMethods = reflections.getMethodsMatchParams(long.class, int.class);
System.out.println("getMethodsMatchParams:" + someMethods);
Set<Method> voidMethods = reflections.getMethodsReturn(void.class);
System.out.println( "getMethodsReturn:" + voidMethods);
Set<Method> pathParamMethods =reflections.getMethodsWithAnyParamAnnotated( PathParam.class);
System.out.println("getMethodsWithAnyParamAnnotated:" + pathParamMethods);
}
}
标签:反射,Set,框架,扫描,Reflections,注解,new,class,reflections 来源: https://www.cnblogs.com/xfeiyun/p/15786771.html