JAVA 使用反射比较对象属性的变化，记录修改日志。使用注解【策略模式】，来进行不同属性枚举值到中英文描述的切换，支持前端国际化。

1.首先定义一个接口，接口中有两个方法，分别是将属性转换成英文描述和中文描述。

其实就是将数据库中记录的 0  1 ，转换成后面的描述

这边定义了中文转换为默认方法，是因为有些属性不需要进行中文转换，或者该属性的枚举值中没有中文描述，你也可以不定义为默认方法

public interface ColumnConverter {/*** 英文值*/Object enConverter(Object value);/*** 中文值*/default Object cnConverter(Object value) {return enConverter(value);}
}

2.然后我们就可以定义一个类，该类中有很多静态类【不同的静态类用于不同属性的枚举值转换】，代码如下

@Slf4j
public class ColumnStrategy {private final Map<Class<? extends ColumnConverter>, ColumnConverter> converterMap = new HashMap<>();private ColumnStrategy() {}/*** 获取单例*/public static ColumnStrategy getInstance() {return INSTANCE.Instance;}public ColumnConverter getConverter(Class<? extends ColumnConverter> converterClass) {try {if (converterMap.containsKey(converterClass)) {return converterMap.get(converterClass);}Constructor<? extends ColumnConverter> constructor = converterClass.getConstructor();ColumnConverter columnConverter = constructor.newInstance();converterMap.put(converterClass, columnConverter);return columnConverter;} catch (Exception e) {log.error("构造转换器对象异常", e);return null;}}public ColumnConverter getDefaultConverter() {ColumnConverter defaultConverter = converterMap.get(AutoConverter.class);if (defaultConverter != null) {return defaultConverter;}AutoConverter autoConverter = new AutoConverter();converterMap.put(AutoConverter.class, autoConverter);return autoConverter;}private static class INSTANCE {private static final ColumnStrategy Instance = new ColumnStrategy();}/*** 默认转换器*/public static class AutoConverter implements ColumnConverter {@Overridepublic Object enConverter(Object value) {return value;}}public static class CarrierLevelType implements ColumnConverter {@Overridepublic Object enConverter(Object value) {return Optional.ofNullable(value).map(e -> CarrierTypeEnum.getByCode((int) e)).map(CarrierTypeEnum::getEnDesc).orElse(null);}@Overridepublic Object cnConverter(Object value) {return Optional.ofNullable(value).map(e -> CarrierTypeEnum.getByCode((int) e)).map(CarrierTypeEnum::getDescription).orElse(null);}}/*** 结果集转换器* 将<转换为&lt; （前端要求）*/public static class OperationDescResultConverter implements ColumnConverter {@Overridepublic Object enConverter(Object value) {return ((String) value).replaceAll(KeyboardSpecialCharConstants.LESS, KeyboardSpecialCharConstants.LESS_ESCAPING);}}public static class BusinessStatusType implements ColumnConverter {@Overridepublic Object enConverter(Object value) {return Optional.ofNullable(value).map(e -> BusinessStatusEnum.getByCode((int) e)).map(BusinessStatusEnum::getValue).orElse(null);}@Overridepublic Object cnConverter(Object value) {return Optional.ofNullable(value).map(e -> BusinessStatusEnum.getByCode((int) e)).map(BusinessStatusEnum::getCnValue).orElse(null);}}public static class PriceCheckType implements ColumnConverter {@Overridepublic Object enConverter(Object value) {return Optional.ofNullable(value).map(e -> PriceCheckModeEnum.getEnumByCode((int) e)).map(PriceCheckModeEnum::getModeDescEn).orElse(null);}@Overridepublic Object cnConverter(Object value) {return Optional.ofNullable(value).map(e -> PriceCheckModeEnum.getEnumByCode((int) e)).map(PriceCheckModeEnum::getModeDesc).orElse(null);}}public static class RealPriceCalType implements ColumnConverter {@Overridepublic Object enConverter(Object value) {return Optional.ofNullable(value).map(e -> RealPriceCalMethodEnum.getEnumByCode((int) e)).map(RealPriceCalMethodEnum::getMethodDescEn).orElse(null);}@Overridepublic Object cnConverter(Object value) {return Optional.ofNullable(value).map(e -> RealPriceCalMethodEnum.getEnumByCode((int) e)).map(RealPriceCalMethodEnum::getMethodDesc).orElse(null);}}}

3.然后我们定义一个注解，该注解用于我们实际进行比较的类中上，具体值是否需要进行枚举值转换，以及字段的中英文名称

@Target(ElementType.FIELD)
@Retention(RetentionPolicy.RUNTIME)
public @interface ColumnInfo {/*** 字段中文名*/String cnName() default "";/*** 字段英文名*/String enName() default "";/*** 值转换器(英文)* 适用于枚举型转换*/Class<? extends ColumnConverter> converter() default ColumnStrategy.AutoConverter.class;/*** 是否是用户数组*/boolean isUserList() default false;
}

4.然后我们就可以在实际需要进行比较的类上加上该注解【需要进行枚举值转换的属性，我们可以在属性上面的注解中加上converter ，然后注入对应的转换器即可】，示例代码如下

@Data
public class DTO {/*** 业务名称*/@ColumnInfo(cnName = "业务名称", enName = "Business name")private String bizCode;/*** 国别*/@ColumnInfo(cnName = "国家", enName = "Country")private String country;/*** 国别*/@ColumnInfo(cnName = "到期时间", enName = "Expire time")private String expireTime;/*** 业务状态*/@ColumnInfo(cnName = "业务状态", enName = "status", converter = ColumnStrategy.BusinessStatusType.class)private Integer status;/*** 是否校验价格*/@ColumnInfo(cnName = "是否校验价格", enName = "Is check price", converter = ColumnStrategy.PriceCheckType.class)private Integer priceCheckMode;}

5.现在就可以直接传入修改前后的两个对象，利用反射对其进行修改值的检测了

//调用示例
getChangeFields(DTO.class, from, to, descCnList, descEnList);    //具体方法代码如下
private void getChangeFields(Class clazz, Object obj1, Objectobj2, ArrayList<String> cnList, ArrayList<String> enList) {try {// 解析对象1和对象2的JSONObjectJSONObject object1 = JSONUtil.parseObj(obj1);JSONObject object2 = JSONUtil.parseObj(obj2);if (object1.isEmpty() || object2.isEmpty()) {return;}// 获取该类的所有属性Field[] fields = clazz.getDeclaredFields();for (Field field : fields) {// 设置属性可访问field.setAccessible(true);// 获取属性名String name = field.getName();ColumnInfo targetColumnInfo = field.getAnnotation(ColumnInfo.class);ColumnConverter columnConverter = getColumnConverter(targetColumnInfo);// 判断对象1和对象2的属性数量是否不为0（如果是创建则object2为null）// 判断对象1和对象2的属性值是否都不为空（由于有一些属性始终为null，所以需要过滤掉，不然会空指针异常）Object o1 = object1.get(name);Object o2 = object2.get(name);// 判断对象1和对象2的属性值是否不相等if (ObjectUtil.equals(o1, o2)) {continue;}if (Constants.CHECK_CONVERT_FILED.contains(name)) {Object cnFrom = ObjectUtil.isNotEmpty(o1) ? columnConverter.cnConverter(o1) : StringPool.EMPTY;Object cnTo = ObjectUtil.isNotEmpty(o2) ? columnConverter.cnConverter(o2) : StringPool.EMPTY;Object enFrom = ObjectUtil.isNotEmpty(o1) ? columnConverter.enConverter(o1) : StringPool.EMPTY;Object enTo = ObjectUtil.isNotEmpty(o2) ? columnConverter.enConverter(o2) : StringPool.EMPTY;// 添加属性名到列表中cnList.add(String.format("%s【%s】更新为【%s】", targetColumnInfo.cnName(), cnFrom, cnTo));enList.add(String.format("%s【%s】 changed to 【%s】", targetColumnInfo.enName(), enFrom, enTo));} else {o1 = ObjectUtil.isNotEmpty(o1) ? o1 : StringPool.EMPTY;o2 = ObjectUtil.isNotEmpty(o2) ? o2 : StringPool.EMPTY;if (ObjectUtil.isNotEmpty(targetColumnInfo.cnName())) {cnList.add(String.format("%s【%s】更新为【%s】", targetColumnInfo.cnName(), o1, o2));}if (ObjectUtil.isNotEmpty(targetColumnInfo.enName())) {enList.add(String.format("%s【%s】 changed to 【%s】", targetColumnInfo.enName(), o1, o2));}}}} catch (Exception e) {// 获取异常信息详情log.error("---Failed to check attributes---", e);}}