Compare the field names and field values extracted from two entity class attributes with different values.

package com.alibaba.thead.util;

import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.sql.Timestamp;
import java.util.Date;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
 * @Author: zhengpengp
 * @Date： 2021/12/15 14:10
 * @Description: 比较实体属性值是否一致
 */
public class ClassCompareUtil {
    /**
     * 比较两个实体属性值，返回一个boolean,true则表时两个对象中的属性值无差异
     *
     * @param oldObject 进行属性比较的对象1
     * @param newObject 进行属性比较的对象2
     * @return 属性差异比较结果boolean
     */
    public static boolean compareObject(Object oldObject, Object newObject) {
        Map<String, Map<String, Object>> resultMap = compareFields(oldObject, newObject);

        if (resultMap.size() > 0) {
            return false;
        } else {
            return true;
        }
    }

    /**
     * 比较两个实体属性值，返回一个map以有差异的属性名为key，value为一个Map分别存oldObject,newObject此属性名的值
     *
     * @param oldObject 进行属性比较的对象1
     * @param newObject 进行属性比较的对象2
     * @return 属性差异比较结果map
     */
    @SuppressWarnings("rawtypes")
    public static Map<String, Map<String, Object>> compareFields(Object oldObject, Object newObject) {
        Map<String, Map<String, Object>> map = null;

        try {
            /**
             * 只有两个对象都是同一类型的才有可比性
             */
            if (oldObject.getClass() == newObject.getClass()) {
                map = new HashMap<String, Map<String, Object>>();

                Class clazz = oldObject.getClass();
                //获取object的所有属性
                PropertyDescriptor[] pds = Introspector.getBeanInfo(clazz, Object.class).getPropertyDescriptors();

                for (PropertyDescriptor pd : pds) {
                    //遍历获取属性名
                    String name = pd.getName();

                    //获取属性的get方法
                    Method readMethod = pd.getReadMethod();

                    // 在oldObject上调用get方法等同于获得oldObject的属性值
                    Object oldValue = readMethod.invoke(oldObject);
                    // 在newObject上调用get方法等同于获得newObject的属性值
                    Object newValue = readMethod.invoke(newObject);

                    if (oldValue instanceof List) {
                        continue;
                    }

                    if (newValue instanceof List) {
                        continue;
                    }

                    if (oldValue instanceof Timestamp) {
                        oldValue = new Date(((Timestamp) oldValue).getTime());
                    }

                    if (newValue instanceof Timestamp) {
                        newValue = new Date(((Timestamp) newValue).getTime());
                    }

                    if (oldValue == null && newValue == null) {
                        continue;
                    } else if (oldValue == null && newValue != null) {
                        Map<String, Object> valueMap = new HashMap<String, Object>();
                        valueMap.put("oldValue", oldValue);
                        valueMap.put("newValue", newValue);

                        map.put(name, valueMap);

                        continue;
                    }

                    if (!oldValue.equals(newValue)) {// 比较这两个值是否相等,不等就可以放入map了
                        Map<String, Object> valueMap = new HashMap<String, Object>();
                        valueMap.put("oldValue", oldValue);
                        valueMap.put("newValue", newValue);

                        map.put(name, valueMap);
                    }
                }
            }
        } catch (Exception e) {
            e.printStackTrace();
        }

        return map;
    }
}