源码分析：Spring 注解别名 - @AliasFor

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总结

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# Spring 解析 @AliasFor
AnnotationTypeMapping.resolveAliasedForTargets

本质（简要说明）：
    根据传入名称 获取方法 Method，invoke 调用方法获取结果
    -> 结果：非空 -> 返回
    -> 结果：空 -> 根据 Method 获取 @AliasFor 属性，获取 aliasMethod 调用获取结果
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代码

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package com.taopanfeng.junit.spring._004_AliasFor;

import cn.hutool.core.lang.Assert;
import cn.hutool.core.util.StrUtil;
import org.springframework.core.annotation.AliasFor;
import org.springframework.core.annotation.MergedAnnotation;
import org.springframework.core.annotation.MergedAnnotations;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;
import java.lang.reflect.Method;
import java.util.Arrays;

/**
 * 描述
 *
 * @author 陶攀峰
 * @date 2024-05-10 18:02
 */
// @MyTest.MyComponent(value = "abc", name = "def")// 不可以同时声明
@MyTest.MyComponent("abc")
public class MyTest {

    @Target({ElementType.TYPE})
    @Retention(RetentionPolicy.RUNTIME)
    @Documented
    @interface MyComponent {
        @AliasFor(attribute = "name")
        String value() default "";

        @AliasFor(attribute = "value")
        String name() default "";
    }

    // 2024-05-10 18:03
    public static void main(String[] args) throws Throwable {
        // 测试1：Spring获取
        MergedAnnotation<MyComponent> anno = MergedAnnotations.from(MyTest.class).get(MyComponent.class);
        Assert.equals(anno.getString("value"), "abc");
        Assert.equals(anno.getString("name"), "abc");
        
        // 测试2：原生代码获取
        MyComponent anno2 = MyTest.class.getAnnotation(MyComponent.class);
        Method method = Arrays.stream(MyComponent.class.getDeclaredMethods()).filter(e -> e.getName().equals("name")).findFirst().orElse(null);
        String value = (String) method.invoke(anno2);
        String aliasName = method.getAnnotation(AliasFor.class).attribute();

        if (StrUtil.isBlank(value)) {
            Method aliasMethod = Arrays.stream(MyComponent.class.getDeclaredMethods()).filter(e -> e.getName().equals(aliasName)).findFirst().orElse(null);
            value = (String) aliasMethod.invoke(anno2);
        }
        System.out.println("name：" + value);// name：abc
    }

}