mybatis-plus/src/main/java/com/baomidou/mybatisplus/mapper/MetaObjectHandler.java

/**
 * Copyright (c) 2011-2020, hubin (jobob@qq.com).
 * <p>
 * Licensed under the Apache License, Version 2.0 (the "License"); you may not
 * use this file except in compliance with the License. You may obtain a copy of
 * the License at
 * <p>
 * http://www.apache.org/licenses/LICENSE-2.0
 * <p>
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
 * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
 * License for the specific language governing permissions and limitations under
 * the License.
 */
package com.baomidou.mybatisplus.mapper;

import org.apache.ibatis.reflection.MetaObject;

/**
 * <p>
 * 元对象字段填充控制器抽象类，实现公共字段自动写入
 * </p>
 *
 * @author hubin
 * @Date 2016-08-28
 */
public abstract class MetaObjectHandler {

    protected static final String META_OBJ_PREFIX = "et";

    /**
     * <p>
     * 插入元对象字段填充
     * </p>
     *
     * @param metaObject 元对象
     */
    public abstract void insertFill(MetaObject metaObject);

    /**
     * 更新元对象字段填充（用于更新时对公共字段的填充）
     * Created with IntelliJ IDEA.
     * Author:  Wu Yujie
     * Email:  coffee377@dingtalk.com
     * Time:  2017/04/16 15:03
     *
     * @param metaObject 元对象
     */
    public abstract void updateFill(MetaObject metaObject);

    /**
     * <p>
     * Common method to set value for java bean.
     * </p>
     * <p>
     * 如果包含前缀 et 使用该方法，否则可以直接 metaObject.setValue(fieldName, fieldVal);
     * </p>
     *
     * @param fieldName  java bean property name
     * @param fieldVal   java bean property value
     * @param metaObject meta object parameter
     */
    public MetaObjectHandler setFieldValByName(String fieldName, Object fieldVal, MetaObject metaObject) {
        if(metaObject.hasGetter(fieldName)) {
            metaObject.setValue(fieldName, fieldVal);
        } else if (this.hasGetter(fieldName, metaObject)) {
            metaObject.setValue(META_OBJ_PREFIX + "." + fieldName, fieldVal);
        }
        return this;
    }

    /**
     * <p>
     * get value from java bean by propertyName
     * </p>
     * <p>
     * 如果包含前缀 et 使用该方法，否则可以直接 metaObject.setValue(fieldName, fieldVal);
     * </p>
     *
     * @param fieldName  java bean property name
     * @param metaObject parameter wrapper
     * @return
     */
    public Object getFieldValByName(String fieldName, MetaObject metaObject) {
        String[] fieldNames = metaObject.getGetterNames();
        boolean containsEt = false;
        for (String name : fieldNames) {
            if (META_OBJ_PREFIX.equals(name)) {
                containsEt = true;
                break;
            }
        }
        if (containsEt) {
            return metaObject.getValue(META_OBJ_PREFIX + "." + fieldName);
        } else {
            return metaObject.getValue(fieldName);
        }
    }

    /**
     * <p>
     * 是否存在属性，判断 et 别名方法
     * </p>
     *
     * @param fieldName  java bean property name
     * @param metaObject parameter wrapper
     * @return
     */
    public boolean hasGetter(String fieldName, MetaObject metaObject) {
        if (metaObject.hasGetter(fieldName)) {
            return true;
        }
        return metaObject.hasGetter(META_OBJ_PREFIX + "." + fieldName);
    }

    /**
     * 开启插入填充
     */
    public boolean openInsertFill() {
        return true;
    }

    /**
     * 开启更新填充
     */
    public boolean openUpdateFill() {
        return true;
    }

}