java获取注解的属性值_反射+自定义注解 实现获取注解标记的属性

目标：通过自定义注解 @Ignore 注解，觉得是否读取指定类的属性。

运行结果：

[main] INFO util.FruitInfoUtil -水果的名字为：entity.Apple

[main] INFO util.FruitInfoUtil-水果的颜色为：RED

[main] INFO util.FruitInfoUtil-水果的供应商名称为：红富士供应商，供应商地址为：山西红富士产业园

[main] INFO main.MainTest- ====================[main] INFO util.FieldsUtil- fieldName:fruitColor's ignore is null

[main] INFO util.FieldsUtil - fieldName:fruitProvider's ignore is false

[main] INFO util.FieldsUtil - fields:

[main] INFO util.FieldsUtil -fruitColor

[main] INFO util.FieldsUtil-fruitProvider

[main] INFO util.FieldsUtil- END

import java.lang.annotation.*;

@Target(ElementType.FIELD)

@Retention(RetentionPolicy.RUNTIME)

@Documented

public @interface FruitName {

String value() default "";

}

import java.lang.annotation.*;

@Target(ElementType.FIELD)

@Retention(RetentionPolicy.RUNTIME)

@Documented

public @interface FruitColor {

public enum Color {GREND, RED, BLUE}

Color fruitColor() default Color.GREND;

}

import java.lang.annotation.*;

@Target(ElementType.FIELD)

@Retention(RetentionPolicy.RUNTIME)

@Documented

public @interface FruitProvider {

int id() default -1;

String name() default "";

String addr() default "";

}

import java.lang.annotation.*;

@Target(ElementType.FIELD)

@Retention(RetentionPolicy.RUNTIME)

@Documented

public @interface Ignore {

boolean ignore() default false;

}

import annotation.FruitColor;

import annotation.FruitName;

import annotation.FruitProvider;

import annotation.Ignore;

public class Apple {

@FruitName("entity.Apple")

@Ignore(ignore = true)

String fruitName;

@FruitColor(fruitColor = FruitColor.Color.RED)

// @Ignore(ignore = true)

String fruitColor;

@FruitProvider(id = 1, name = "红富士供应商", addr = "山西红富士产业园")

@Ignore

String fruitProvider;

public String getFruitName() {

return fruitName;

}

public void setFruitName(String fruitName) {

this.fruitName = fruitName;

}

public String getFruitColor() {

return fruitColor;

}

public void setFruitColor(String fruitColor) {

this.fruitColor = fruitColor;

}

public String getFruitProvider() {

return fruitProvider;

}

public void setFruitProvider(String fruitProvider) {

this.fruitProvider = fruitProvider;

}

public void getAppleName(){

System.out.println("水果的名称为：苹果。");

}

}

import annotation.FruitColor;

import annotation.FruitName;

import annotation.FruitProvider;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import java.lang.reflect.Field;

public class FruitInfoUtil {

final static Logger logger = LoggerFactory.getLogger(FruitInfoUtil.class);

public static void getAnnotationInfo(Class clazz){

Field[] fields = clazz.getDeclaredFields();

for (Field field : fields) {

if(field.isAnnotationPresent(FruitName.class)){

FruitName fruitName = field.getAnnotation(FruitName.class);

logger.info("水果的名字为："+fruitName.value());

}

else if(field.isAnnotationPresent(FruitColor.class)) {

FruitColor fruitColor = field.getAnnotation(FruitColor.class);

logger.info("水果的颜色为：" + fruitColor.fruitColor());

}

else if(field.isAnnotationPresent(FruitProvider.class)){

FruitProvider fruitProvider = field.getAnnotation(FruitProvider.class);

logger.info("水果的供应商名称为：" + fruitProvider.name()+"，供应商地址为："+fruitProvider.addr());

}

}

}

}

import annotation.Ignore;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import java.lang.reflect.Field;

import java.util.ArrayList;

import java.util.List;

public class FieldsUtil {

final static Logger logger = LoggerFactory.getLogger(FieldsUtil.class);

/**

* 本类的所有 Ignore = false的字段集合

* @param clazz

*/

public static void getOneSelfActiveFieldsUtil(Class clazz){

Field[] fields = clazz.getDeclaredFields();

List fileNames = new ArrayList<>();

for (Field field : fields){

String fieldName = field.getName();

Ignore ignoreField = field.getAnnotation(Ignore.class);

if(field.isAnnotationPresent(Ignore.class) && !ignoreField.ignore()){

fileNames.add(field.getName());

logger.info("fieldName:"+fieldName+"'s ignore is false");

}

else if(!field.isAnnotationPresent(Ignore.class)){

fileNames.add(field.getName());

logger.info("fieldName:"+fieldName+"'s ignore is null");

}

}

logger.info("fields:");

if(fileNames != null && fileNames.size() > 0){

// fileNames.stream().forEach(System.out::println);

fileNames.stream().forEach(y -> {

logger.info(y);

});

}else{

logger.info("Size() == 0 ");

}

logger.info("END");

}

/**

* 包括 父类的所有Ignore = false(默认值)的字段信息

* @param clazz

*/

public static List getAllActiveFieldsUtil(Class clazz){

List fileNames = new ArrayList<>();

List fieldList = null;

Field[] fields;

do{

fields = clazz.getDeclaredFields();

if(fields != null && fields.length > 0){

for (Field field : fields){

String fieldName = field.getName();

Ignore ignoreField = field.getAnnotation(Ignore.class);

if(field.isAnnotationPresent(Ignore.class) && !ignoreField.ignore()){

fileNames.add(field.getName());

logger.info("fieldName:"+fieldName+"'s ignore is false");

fieldList.add(field);

}

else if(!field.isAnnotationPresent(Ignore.class)){

fileNames.add(field.getName());

logger.info("fieldName:"+fieldName+"'s ignore is null");

fieldList.add(field);

}

}

if(fileNames != null && fileNames.size() > 0){

fileNames.stream().forEach(System.out::println);

}else{

logger.info("Size() == 0 ");

}

logger.info("END");

}

clazz = clazz.getSuperclass();

}while (clazz != Object.class && clazz != null);

return fieldList;

}

}

import entity.Apple;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import util.FieldsUtil;

import util.FruitInfoUtil;

public class MainTest {

final static Logger logger = LoggerFactory.getLogger(MainTest.class);

public static void main(String[] args) {

FruitInfoUtil.getAnnotationInfo(Apple.class);

logger.info("====================");

FieldsUtil.getOneSelfActiveFieldsUtil(Apple.class);

}

}

参考资源：

/acm-bingzi/p/javaAnnotation.html

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