find Field Annotation By Annotation Class - Java java.lang.annotation

Java examples for java.lang.annotation:Field Annotation

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Description

find Field Annotation By Annotation Class

Demo Code


//package com.java2s;
import java.lang.annotation.Annotation;
import java.lang.reflect.Field;

import java.util.ArrayList;
import java.util.List;

public class Main {
    public static void main(String[] argv) throws Exception {
        Class clazz = String.class;
        String fieldName = "java2s.com";
        Class annotationClass = String.class;
        System.out.println(java.util.Arrays
                .toString(findFieldAnnotationByAnnotationClass(clazz,
                        fieldName, annotationClass)));
    }/*from  w w  w . j  av a2  s  .c  om*/

    public static Object[] findFieldAnnotationByAnnotationClass(
            Class<?> clazz, String fieldName,
            Class<? extends Annotation> annotationClass) {
        Annotation[] allAnnotations = findFieldAnnotation(clazz, fieldName);
        ArrayList<Annotation> annotations = new ArrayList<Annotation>();
        if (allAnnotations != null) {
            for (int i = 0; i < allAnnotations.length; i++) {
                Annotation annotation = allAnnotations[i];
                if (annotation.annotationType().equals(annotationClass)) {
                    annotations.add(annotation);
                }
            }
            return annotations.toArray();
        } else {
            return null;
        }
    }

    public static Annotation[] findFieldAnnotation(Class<?> clazz,
            String fieldName) {
        Annotation[] annotations = null;
        try {
            List<Field> fields = getAllFields(clazz);
            Field field = null;
            for (Field fld : fields) {
                if (fld.getName().equals(fieldName)) {
                    field = fld;
                    break;
                }
            }
            if (field != null) {
                annotations = field.getAnnotations();
            }
        } catch (SecurityException e) {
        }
        return annotations;
    }

    public static List<Field> getAllFields(Class<?> type) {
        return getAllFields(null, type);
    }

    private static List<Field> getAllFields(List<Field> fields,
            Class<?> type) {
        if (fields == null)
            fields = new ArrayList<Field>();
        for (Field field : type.getDeclaredFields()) {
            fields.add(field);
        }

        if (type.getSuperclass() != null) {
            fields = getAllFields(fields, type.getSuperclass());
        }

        return fields;
    }
}

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