java动态给对象添加属性并赋值

版权声明：转载请加链接 https://blog.csdn.net/y526089989/article/details/89389087

最近工作中剥离通用功能比较多。

Maven引用：

       <!-- https://mvnrepository.com/artifact/cglib/cglib -->
        <dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>2.2.2</version>
        </dependency>

不要引用太高级的版本。会存在兼容问题。本身有内部依赖。

核心类：

import net.sf.cglib.beans.*;

import java.util.*;

public class DynamicBean {
    private Object object = null; //动态生成的类
    private BeanMap beanMap = null; //存放属性名称以及属性的类型

    public DynamicBean() {
        super();
    }

    public DynamicBean(Map propertyMap) {
        this.object = generateBean(propertyMap);
        this.beanMap = BeanMap.create(this.object);
    }

    /**
     * @param propertyMap
     * @return
     */
    private Object generateBean(Map propertyMap) {
        BeanGenerator generator = new BeanGenerator();
        Set keySet = propertyMap.keySet();
        for (Iterator i = keySet.iterator(); i.hasNext(); ) {
            String key = (String) i.next();
            generator.addProperty(key, (Class) propertyMap.get(key));
        }
        return generator.create();
    }

    /**
     * 给bean属性赋值
     *
     * @param property 属性名
     * @param value    值
     */
    public void setValue(Object property, Object value) {
        beanMap.put(property, value);
    }

    /**
     * 通过属性名得到属性值
     *
     * @param property 属性名
     * @return 值
     */
    public Object getValue(String property) {
        return beanMap.get(property);
    }

    /**
     * 得到该实体bean对象
     *
     * @return
     */
    public Object getObject() {
        return this.object;
    }
}

帮助类：

import java.beans.BeanInfo;
import java.beans.Introspector;
import java.beans.PropertyDescriptor;
import java.lang.reflect.Method;
import java.util.*;

public class ClassUtil {

    /**
     *
     * @param object   旧的对象带值
     * @param addMap   动态需要添加的属性和属性类型
     * @param addValMap  动态需要添加的属性和属性值
     * @return  新的对象
     * @throws Exception
     */
    public Object dynamicClass(Object object,HashMap addMap, HashMap addValMap) throws Exception {
        HashMap returnMap = new HashMap();
        HashMap typeMap = new HashMap();


        Class<?> type = object.getClass();
        BeanInfo beanInfo = Introspector.getBeanInfo(type);
        PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
        for (int i = 0; i < propertyDescriptors.length; i++) {
            PropertyDescriptor descriptor = propertyDescriptors[i];
            String propertyName = descriptor.getName();
            if (!propertyName.equals("class")) {
                Method readMethod = descriptor.getReadMethod();
                Object result = readMethod.invoke(object);
                //可以判断为 NULL不赋值
                returnMap.put(propertyName, result);
                typeMap.put(propertyName, descriptor.getPropertyType());
            }
        }

        returnMap.putAll(addValMap);
        typeMap.putAll(addMap);
        //map转换成实体对象
        DynamicBean bean = new DynamicBean(typeMap);
        //赋值
        Set keys = typeMap.keySet();
        for (Iterator it = keys.iterator(); it.hasNext(); ) {
            String key = (String) it.next();
            bean.setValue(key, returnMap.get(key));
        }
        Object obj = bean.getObject();
        return obj;
    }

}

使用：

        Order order = new Order();
        order.setId(1);
        order.setName("order1");
        List<OrderDetail> orderDetailList = new ArrayList<OrderDetail>();

        OrderDetail orderDetail = new OrderDetail();
        orderDetail.setOrderid(1);
        orderDetail.setOrderPrice("1USD");
        orderDetail.setOrderSku("Sku1");

        orderDetailList.add(orderDetail);

        OrderDetail orderDetail2 = new OrderDetail();
        orderDetail2.setOrderid(1);
        orderDetail2.setOrderPrice("2USD");
        orderDetail2.setOrderSku("Sku2");
        orderDetailList.add(orderDetail2);

        try {
            HashMap addMap = new HashMap();
            HashMap addValMap = new HashMap();
            addMap.put("orderDetail", Class.forName("java.util.List"));
            addValMap.put("orderDetail", orderDetailList);
            Object obj2= new ClassUtil().dynamicClass(order,addMap,addValMap);

            System.out.println(JSON.toJSONString(obj2));
        } catch (Exception e) {
            e.printStackTrace();
        }