动态生成某个类的子类，并写入新的字段

 

public class ClassUtil {

    /**
     * 生成src类的子类,然后以newParName为字段把add写入新的子类
     */
    public static Object covert(String newParName,Object src, Object add){
        try {
            HashMap> addMap = new HashMap<>();
            HashMap addValMap = new HashMap<>();
            addMap.put(newParName, Class.forName("java.lang.Object"));
            addValMap.put(newParName, add);
            return dynamicClass(src,addMap,addValMap,src.getClass());
        } catch (Exception e) {
            e.printStackTrace();
        }
        return null;
    }
    
    /**
     *
     * @param object   旧的对象
     * @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
     */
    public static Object dynamicClass(Object object,HashMap> addMap,
                                      HashMap addValMap,Class supperClass) throws Exception {
        HashMap returnMap = new HashMap<>();
        HashMap> typeMap = new HashMap<>();


        Class type = object.getClass();
        BeanInfo beanInfo = Introspector.getBeanInfo(type);
        PropertyDescriptor[] propertyDescriptors = beanInfo.getPropertyDescriptors();
        for (PropertyDescriptor descriptor : propertyDescriptors) {
            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, supperClass);
        //赋值
        Set keys = typeMap.keySet();
        for (String key : keys) {
            bean.setValue(key, returnMap.get(key));
        }
        return bean.getObject();
    }

}

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

    public DynamicBean(HashMap> propertyMap , Class supperClass) {
        this.object = generateBean(propertyMap, supperClass);
        this.beanMap = BeanMap.create(this.object);
    }

    private Object generateBean(HashMap> propertyMap,Class supperClass) {
        BeanGenerator generator = new BeanGenerator();
        Set keySet = propertyMap.keySet();
        for (String key : keySet) {
            generator.addProperty(key, propertyMap.get(key));
        }
        generator.setSuperclass(supperClass);
        return generator.create();
    }

    public void setValue(Object property, Object value) {
        beanMap.put(property, value);
    }

    public Object getValue(String property) {
        return beanMap.get(property);
    }

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