Unsafe类 getField 与 getDeclaredField 区别

getField

    @CallerSensitive
    public Field getField(String name)
        throws NoSuchFieldException, SecurityException {
        checkMemberAccess(Member.PUBLIC, Reflection.getCallerClass(), true);
        Field field = getField0(name);
        if (field == null) {
            throw new NoSuchFieldException(name);
        }
        return field;
    }

只能获取Public的属性字段。

getDeclaredField

    @CallerSensitive
    public Field getDeclaredField(String name)
        throws NoSuchFieldException, SecurityException {
        checkMemberAccess(Member.DECLARED, Reflection.getCallerClass(), true);
        Field field = searchFields(privateGetDeclaredFields(false), name);
        if (field == null) {
            throw new NoSuchFieldException(name);
        }
        return field;
    }

可以获取任何属性字段。