Java动态增加实体类的属性

1、DynamicBean

import org.springframework.cglib.beans.BeanGenerator;
import org.springframework.cglib.beans.BeanMap;

import java.util.Map;

public class DynamicBean {
          
   

    /**
     * 目标对象
     */
    private Object target;

    /**
     * 属性集合
     */
    private BeanMap beanMap;

    public DynamicBean(Class superclass, Map<String, Class> propertyMap) {
          
   
        this.target = generateBean(superclass, propertyMap);
        this.beanMap = BeanMap.create(this.target);
    }

    /**
     * bean 添加属性和值
     *
     * @param property
     * @param value
     */
    public void setValue(String property, Object value) {
          
   
        beanMap.put(property, value);
    }

    /**
     * 获取属性值
     *
     * @param property
     * @return
     */
    public Object getValue(String property) {
          
   
        return beanMap.get(property);
    }

    /**
     * 获取对象
     *
     * @return
     */
    public Object getTarget() {
          
   
        return this.target;
    }


    /**
     * 根据属性生成对象
     *
     * @param superclass
     * @param propertyMap
     * @return
     */
    private Object generateBean(Class superclass, Map<String, Class> propertyMap) {
          
   
        BeanGenerator generator = new BeanGenerator();
        if (null != superclass) {
          
   
            generator.setSuperclass(superclass);
        }
        BeanGenerator.addProperties(generator, propertyMap);
        return generator.create();
    }

}

2、BeanAddPropertiesUtil

import com.google.common.collect.Maps;
import org.apache.commons.beanutils.PropertyUtilsBean;

import java.beans.PropertyDescriptor;
import java.util.Map;

public class BeanAddPropertiesUtil {
          
   
    public static Object getTarget(Object dest, Map<String, Object> addProperties) {
          
   
        // get property map
        PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();
        PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(dest);
        Map<String, Class> propertyMap = Maps.newHashMap();
        for (PropertyDescriptor d : descriptors) {
          
   
            if (!"class".equalsIgnoreCase(d.getName())) {
          
   
                propertyMap.put(d.getName(), d.getPropertyType());
            }
        }
        // add extra properties
        addProperties.forEach((k, v) -> propertyMap.put(k, v.getClass()));
        // new dynamic bean
        DynamicBean dynamicBean = new DynamicBean(dest.getClass(), propertyMap);
        // add old value
        propertyMap.forEach((k, v) -> {
          
   
            try {
          
   
                // filter extra properties
                if (!addProperties.containsKey(k)) {
          
   
                    dynamicBean.setValue(k, propertyUtilsBean.getNestedProperty(dest, k));
                }
            } catch (Exception e) {
          
   
                e.printStackTrace();
            }
        });
        // add extra value
        addProperties.forEach((k, v) -> {
          
   
            try {
          
   
                dynamicBean.setValue(k, v);
            } catch (Exception e) {
          
   
                e.printStackTrace();
            }
        });
        Object target = dynamicBean.getTarget();
        return target;

    }
}

3、实际运用：

OrderUserOrderMerchantDTO orderMerchantDTO = new OrderUserOrderMerchantDTO ();
orderMerchantDTO.setRealName(***);
Map<String, Object> map = new HashMap<>();
//通过list动态添加属性
if (CollectionUtils.isNotEmpty(orderMerchandiseList)) {
          
   
    List<String> orderNumberList = orderMerchandiseList.stream().map(OrderUserOrderMerchandiseVO::getOrderNumber).collect(Collectors.toList());
    for (int i = 0, j = orderNumberList.size(); i < j; i++) {
          
   
        map.put("orderNumber" + i, orderNumberList.get(i));
    }
}
OrderUserOrderMerchantDTO merchantDTO = (OrderUserOrderMerchantDTO) BeanAddPropertiesUtil.getTarget(orderMerchantDTO, map);
//增加后的实体对象引用
 String jsonStr = toJSONString(merchantDTO);