您的当前位置:首页正文

Java比较两个对象是否相同并获取值不同的属性

2024-11-07 来源:个人技术集锦

最新项目中要加操作日志,同时要把用户修改了那些字段记录下来,在更新的时候就需要比较之前的数据和现在的数据有哪些不同,这么多类一个一个的比较就太麻烦了,所以打算写一个工具类。
主要思想还是通过反射获取类的属性的getter方法,调用getter方法获取值并比较是否相同,相同就忽略不同就返回属性信息,方法都不复杂,主要是利用反射思想。

代码如下:
定义一个类保存比较后的返回值信息

@Data
public class PropertyModelInfo {
    //属性名
    private String propertyName;
    // 属性值
    private Object value;
    // 返回值类型
    private Class<?> returnType;
}

修改后的属性信息:

public class ModifiedPropertyInfo implements Serializable {

    // 对应的属性名
    private String propertyName;

    // 未修改之前的值
    private Object oldValue;

    // 修改后的值
    private Object newValue;
}

逻辑代码:


/**
     *  比较两个对象属性值是否相同
     *  如果不同返回修改过的属性信息
     * @param oldObj
     * @param newObj
     * @param ignoreProperties
     * @param <T>
     * @return 修改过的属性字段
     */
    public static <T> List<ModifiedPropertyInfo> getDifferentProperty(T oldObj , T newObj , String... ignoreProperties){
        if (oldObj != null && newObj != null) {
            // 比较全部字段
            if (ignoreProperties == null || ignoreProperties.length > 0) {
                if (oldObj.equals(newObj)) {
                    return Collections.emptyList();
                }
            }
            List<PropertyModelInfo> oldObjectPropertyValue = getObjectPropertyValue(oldObj, ignoreProperties);
            if (!CollectionUtils.isEmpty(oldObjectPropertyValue)) {
                List<ModifiedPropertyInfo> modifiedPropertyInfos = new ArrayList<>(oldObjectPropertyValue.size());

                List<PropertyModelInfo> newObjectPropertyValue = getObjectPropertyValue(newObj, ignoreProperties);
                Map<String , Object> objectMap = new HashMap<>(newObjectPropertyValue.size());
                // 获取新对象所有属性值
                for (PropertyModelInfo propertyModelInfo : newObjectPropertyValue) {
                    String propertyName = propertyModelInfo.getPropertyName();
                    Object value = propertyModelInfo.getValue();
                    objectMap.put(propertyName , value);
                }

                for (PropertyModelInfo propertyModelInfo : oldObjectPropertyValue) {
                    String propertyName = propertyModelInfo.getPropertyName();
                    Object value = propertyModelInfo.getValue();
                    if (objectMap.containsKey(propertyName)) {
                        Object newValue = objectMap.get(propertyName);
                        ModifiedPropertyInfo modifiedPropertyInfo = new ModifiedPropertyInfo();
                        if (value != null && newValue != null) {
                            if (!value.equals(newValue)) {
                                modifiedPropertyInfo.setPropertyName(propertyName);
                                modifiedPropertyInfo.setOldValue(value);
                                modifiedPropertyInfo.setNewValue(newValue);
                                modifiedPropertyInfos.add(modifiedPropertyInfo);
                            }
                        }else if (value != null && newValue == null || value== null && newValue != null){
                            modifiedPropertyInfo.setPropertyName(propertyName);
                            modifiedPropertyInfo.setOldValue(value);
                            modifiedPropertyInfo.setNewValue(newValue);
                            modifiedPropertyInfos.add(modifiedPropertyInfo);
                        }
                    }
                }
                return modifiedPropertyInfos;
            }
        }
        return Collections.emptyList();
    }


 /**
     *  通过反射获取对象的属性名称、getter返回值类型、属性值等信息
     * @param obj
     * @param ignoreProperties
     * @param <T>
     * @return
     */
    public static  <T> List<PropertyModelInfo> getObjectPropertyValue(T obj , String... ignoreProperties){
        if (obj != null) {

            Class<?> objClass = obj.getClass();
            PropertyDescriptor[] propertyDescriptors = BeanUtils.getPropertyDescriptors(objClass);
            List<PropertyModelInfo> modelInfos = new ArrayList<>(propertyDescriptors.length);

            List<String> ignoreList = (ignoreProperties != null ? Arrays.asList(ignoreProperties) : null);
            for (PropertyDescriptor propertyDescriptor : propertyDescriptors) {
                Method readMethod = propertyDescriptor.getReadMethod();
                String name = propertyDescriptor.getName();
                if (readMethod != null && (ignoreList == null || !ignoreList.contains(name))) {
                    Object invoke = null;
                    Class<?> returnType = readMethod.getReturnType();
                    try {
                        invoke = readMethod.invoke(obj);
                        PropertyModelInfo propertyModelInfo = new PropertyModelInfo();
                        propertyModelInfo.setPropertyName(name);
                        propertyModelInfo.setValue(invoke);
                        propertyModelInfo.setReturnType(returnType);
                        modelInfos.add(propertyModelInfo);
                    } catch (IllegalAccessException | InvocationTargetException e) {
                        LOGGER.error("反射获取类【"+objClass.getName()+"】方法异常," , e);
                    }
                }
            }
            return modelInfos;
        }
        return Collections.emptyList();
    }

 

测试:

  HouseInfo houseInfo = new HouseInfo();
        houseInfo.setAddress("test1");

        HouseInfo houseInfo2 = new HouseInfo();
        houseInfo2.setAddress("test2");

        //改变值
        List<ModifiedPropertyInfo> modifiedPropertyInfos = ReflectUtil.getDifferentProperty(houseInfo, houseInfo2);
        System.out.println(modifiedPropertyInfos);
        // 不改变值
        houseInfo2.setAddress("test1");
        modifiedPropertyInfos = ReflectUtil.getDifferentProperty(houseInfo, houseInfo2);
        System.out.println(modifiedPropertyInfos);

结果:

[ModifiedPropertyInfo(propertyName=address, oldValue=test1, newValue=test2)]
[]

步骤:
1、获取对象的属性属性值
2、跟另一个对象的所有属性值比较

能力一般,水平有限,如有错误,请多指出

Top