CGLIB基于一个已有类动态生成一个子类bean（转）

<dependency>
            <groupId>cglib</groupId>
            <artifactId>cglib</artifactId>
            <version>3.3.0</version>
        </dependency>

        <dependency>
            <groupId>commons-beanutils</groupId>
            <artifactId>commons-beanutils</artifactId>
            <version>1.9.3</version>
        </dependency>

 

转载：http://www.zzvips.com/article/182396.html

根据旧对象生成一个新对象，且新对象的类是旧对象的所属类的子类

import com.alibaba.fastjson.JSON;
import net.sf.cglib.beans.BeanGenerator;
import net.sf.cglib.beans.BeanMap;
import org.apache.commons.beanutils.PropertyUtilsBean;

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

/**
 * @Author : wangbin
 * @Date : 2023/3/13 16:04
 * @Description: 从一个旧对象生成一个新对象
 */
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();
    }

    public static Object getTarget(Object dest, Map<String, Object> addProperties) {
        // 获取属性map
        PropertyUtilsBean propertyUtilsBean = new PropertyUtilsBean();
        PropertyDescriptor[] descriptors = propertyUtilsBean.getPropertyDescriptors(dest);
        Map<String, Class> propertyMap = new HashMap<>();
        for (PropertyDescriptor d : descriptors) {
            if (!"class".equalsIgnoreCase(d.getName())) {
                propertyMap.put(d.getName(), d.getPropertyType());
            }
        }
        // 添加新属性
        addProperties.forEach((k, v) -> propertyMap.put(k, v.getClass()));
        // 创建动态bean
        DynamicBean dynamicBean = new DynamicBean(dest.getClass(), propertyMap);
        // 给bean添加旧数据
        propertyMap.forEach((k, v) -> {
            try {
                if (!addProperties.containsKey(k)) {
                    dynamicBean.setValue(k, propertyUtilsBean.getNestedProperty(dest, k));
                }
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
        // 添加新数据
        addProperties.forEach((k, v) -> {
            try {
                dynamicBean.setValue(k, v);
            } catch (Exception e) {
                e.printStackTrace();
            }
        });
        return dynamicBean.getTarget();
    }

    public static void main(String[] args) {
        User entity = new User();
        entity.setName("eee");
        entity.setAge(222);
        Map<String, Object> addProperties = new HashMap<>() {{
            put("newKey", "newVal");
        }};
        User finalPicBaseReqVo = (User) getTarget(entity, addProperties);
        System.out.println(JSON.toJSONString(finalPicBaseReqVo));
    }
}