truePerson{name=‘people‘}

import org.springframework.beans.BeanUtils;public class Test {    public static void main(String[] args) {        Person person = new Person("people");        Male male = new Male();        BeanUtils.copyProperties(person, male);                System.out.println(Male.class.isInstance(male));        System.out.println(male);    }}class Person {    private String name;    public Person() {    }    public Person(String name) {        this.name = name;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    @Override    public String toString() {        return "Person{" +                "name=‘" + name + ‘\‘‘ +                ‘}‘;    }}class Male extends Person {    private String necklace;    public Male() {    }    public Male(String name) {        super(name);    }    public String getNecklace() {        return necklace;    }    public void setNecklace(String necklace) {        this.necklace = necklace;    }}

    /**     * Copy the property values of the given source bean into the target bean.     * <p>Note: The source and target classes do not have to match or even be derived     * from each other, as long as the properties match. Any bean properties that the     * source bean exposes but the target bean does not will silently be ignored.     * <p>This is just a convenience method. For more complex transfer needs,     * consider using a full BeanWrapper.     * @param source the source bean     * @param target the target bean     * @throws BeansException if the copying failed     * @see BeanWrapper     */    public static void copyProperties(Object source, Object target) throws BeansException {        copyProperties(source, target, null, (String[]) null);    }

    /**     * Copy the property values of the given source bean into the given target bean.     * <p>Note: The source and target classes do not have to match or even be derived     * from each other, as long as the properties match. Any bean properties that the     * source bean exposes but the target bean does not will silently be ignored.     * @param source the source bean     * @param target the target bean     * @param editable the class (or interface) to restrict property setting to     * @param ignoreProperties array of property names to ignore     * @throws BeansException if the copying failed     * @see BeanWrapper     */    private static void copyProperties(Object source, Object target, Class<?> editable, String... ignoreProperties)            throws BeansException {        Assert.notNull(source, "Source must not be null");        Assert.notNull(target, "Target must not be null");        Class<?> actualEditable = target.getClass();        if (editable != null) {            if (!editable.isInstance(target)) {                throw new IllegalArgumentException("Target class [" + target.getClass().getName() +                        "] not assignable to Editable class [" + editable.getName() + "]");            }            actualEditable = editable;//如果editable赋值，则ignore Target中的字段属性        }        PropertyDescriptor[] targetPds = getPropertyDescriptors(actualEditable);        List<String> ignoreList = (ignoreProperties != null ? Arrays.asList(ignoreProperties) : null);        for (PropertyDescriptor targetPd : targetPds) {            Method writeMethod = targetPd.getWriteMethod();            if (writeMethod != null && (ignoreList == null || !ignoreList.contains(targetPd.getName()))) {                PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());                if (sourcePd != null) {                    Method readMethod = sourcePd.getReadMethod();                    if (readMethod != null &&                            ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType())) {                        try {                            if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {                                readMethod.setAccessible(true);                            }                            Object value = readMethod.invoke(source);                            if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {                                writeMethod.setAccessible(true);                            }                            writeMethod.invoke(target, value);                        }                        catch (Throwable ex) {                            throw new FatalBeanException(                                    "Could not copy property ‘" + targetPd.getName() + "‘ from source to target", ex);                        }                    }                }            }        }    }