Java代码实现获取对象被更新的属性和值

蔚落 2024-03-17 15:35 12阅读 0赞

## 诉求 ##

更新`User`后，收集哪些字段的哪些值被更新了

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## 思路 ##

比较`originUser`和`newUser`，收集值不同的属性以及变化前后的值。

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## 代码实现 ##

import com.google.common.collect.Maps;
    import lombok.extern.slf4j.Slf4j;
    import org.apache.commons.lang3.ObjectUtils;
    
    import java.beans.IntrospectionException;
    import java.beans.PropertyDescriptor;
    import java.lang.reflect.Field;
    import java.lang.reflect.InvocationTargetException;
    import java.lang.reflect.Method;
    import java.util.HashMap;
    import java.util.Map;
    import java.util.Objects;
    
    public static Map<String, Map<String, Object>> getChange(Object originObject, Object newObject) {
        
            # 存在为null比较就没意义了
            if (ObjectUtils.anyNull(originObject, newObject)) {
        
                return new HashMap<>();
            }
    
            # 不同类型无法比较
            if (ObjectUtils.notEqual(originObject.getClass(), newObject.getClass())) {
        
                return new HashMap<>();
            }
    
            # 内容都相等所以没必要比较
            if (Objects.deepEquals(originObject, newObject)) {
        
                return new HashMap<>();
            }
    
            Map<String, Map<String, Object>> res = Maps.newHashMap();
    
            Field[] declaredFields = originObject.getClass().getDeclaredFields();
            for (Field field : declaredFields) {
        
                # 检查Field是否为合成字段、如果该字段是合成字段则不进行比较
                if (field.isSynthetic()) {
        
                    continue;
                }
    
                # serialVersionUID适用于java序列化机制,非业务属性
                if ("serialVersionUID".equals(field.getName())) {
        
                    continue;
                }
    
                # 实现方式1
                // field.setAccessible(true);
                // Object o = field.get(originObject);
                // Object n = field.get(originObject);
    
                # 实现方式2
                PropertyDescriptor propertyDescriptor = null;
                try {
        
                    propertyDescriptor = new PropertyDescriptor(field.getName(), originObject.getClass());
                    Method readMethod = propertyDescriptor.getReadMethod();
                    Object originValue = readMethod.invoke(originObject);
                    Object newValue = readMethod.invoke(newObject);
                    
                    if (!Objects.deepEquals(originValue, newValue)) {
        
                        # 值不相等的话记录属性和值
                        HashMap<String, Object> keyValue = new HashMap();
                        keyValue.put("origin", originValue);
                        keyValue.put("new", newValue);
                        res.put(field.getName(), keyValue);
                    }
                } catch (IntrospectionException | IllegalAccessException | InvocationTargetException e) {
        
                    log.error("getChange occur error" + e.getMessage());
                }
    
            }
            return res;
        }

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## 测试验证 ##

public class MethodUtilsTest {
        
    
        @Test
        public void getChangeNoChange() {
        
            User user1 = new User();
            user1.setName("user2");
            user1.setAge("19");
            user1.setNum("123456");
    
            User user2 = new User();
            user2.setName("user2");
            user2.setAge("19");
            user2.setNum("123456");
    
            Map<String, Map<String, Object>> change = MethodUtils.getChange(user1, user2);
            Assert.assertEquals("{}", change.toString());
        }
    
        @Test
        public void getChangeWithChange() {
        
            User user1 = new User();
            user1.setName("user1");
            user1.setAge("19");
            user1.setNum("123456");
    
            User user2 = new User();
            user2.setName("user2");
            user2.setAge("18");
            user2.setNum("123457");
    
            Map<String, Map<String, Object>> change = MethodUtils.getChange(user1, user2);
            Assert.assertEquals("{num={new=123457, origin=123456}, name={new=user2, origin=user1}, age={new=18, origin=19}}", change.toString());
        }
    
        @Data
        static class User {
        
            private String name;
            private String age;
            private String num;
        }
    }

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## 参考 ##

[对象被更新后、获取更新了的属性和值][Link 1]

[Link 1]: https://juejin.cn/post/7106887917234028558