randomObject 根据类随机生成对象

• 自动生成的时候用了 hutool 和 commons-lang3 ，这个可以用 java 原生的 random 生成

		<dependency>
            <groupId>org.apache.commons</groupId>
            <artifactId>commons-lang3</artifactId>
            <version>3.8</version>
        </dependency>
        
        <dependency>
            <groupId>cn.hutool</groupId>
            <artifactId>hutool-all</artifactId>
            <version>5.1.5</version>
        </dependency>

• 运用 java 反射 实现对象的创建和属性的赋值

public class Util {

    /**
     * 根据 类 创建一个随机生成对象
     */
    public static Object randomObject(Class<?> clazz) {
        Class sourceClass = clazz;
        Object obj = null;
        try {
            obj = clazz.newInstance();
            //获取对象所有字段 包括父类
            ArrayList<Field> fields = new ArrayList<>();
            while (sourceClass != null) {
                fields.addAll(Arrays.asList(sourceClass.getDeclaredFields()));
                sourceClass = sourceClass.getSuperclass();
            }
            for (Field field : fields) {
                //todo:通过自定义注解去筛掉哪些需要自动赋值，哪些不需要
                Class<?> type = parseClass(field.getType());
                field.setAccessible(true);
                try {
                    if (String.class.isAssignableFrom(type)) {
                        field.set(obj, RandomUtil.randomString(5));
                    } else if (Date.class.isAssignableFrom(type)) {
                        field.set(obj, randomDate());
                    } else if (Boolean.class.isAssignableFrom(type)) {
                        field.set(obj, RandomUtil.randomBoolean());
                    } else if (Character.class.isAssignableFrom(type)) {
                        field.set(obj, RandomUtil.randomChar());
                    } else if (Number.class.isAssignableFrom(type)) {
                        if (Byte.class.isAssignableFrom(type)) {
                            field.set(obj, RandomUtil.randomBytes(1)[0]);
                        } else if (Short.class.isAssignableFrom(type)) {
                            short ashort = (short) (RandomUtil.randomInt(0, 99999) & 0x7FFF);
                            field.set(obj, ashort);
                        } else if (Integer.class.isAssignableFrom(type)) {
                            field.set(obj, RandomUtil.randomInt(0, 99999));
                        } else if (Long.class.isAssignableFrom(type)) {
                            field.set(obj, RandomUtil.randomLong(0, 9999));
                        } else if (Float.class.isAssignableFrom(type)) {
                            field.set(obj, RandomUtils.nextFloat(100, 9999));
                        } else if (Double.class.isAssignableFrom(type)) {
                            field.set(obj, RandomUtil.randomDouble(10, 99999, 2, RoundingMode.DOWN));
                        }
                    } else {
                        //以上类型都不是，就递归生成
                        field.set(obj, randomObject(type));
                    }
                } catch (IllegalAccessException e) {
                    e.printStackTrace();
                }
            }
        } catch (InstantiationException | IllegalAccessException e) {
            e.printStackTrace();
        }
        return obj;
    }

    private static Date randomDate() {
        DateTime baseDate = DateUtil.parse("1980-01-01");
        DateTime dateTime = RandomUtil.randomDate(baseDate, DateField.DAY_OF_YEAR, 0, 4000);
        return dateTime;
    }

    /**
     * 将基础类和包装类相对应
     * java.lang.Boolean#TYPE == boolean
     * java.lang.Character#TYPE == character
     * java.lang.Byte#TYPE == byte
     * java.lang.Short#TYPE == short
     * java.lang.Integer#TYPE == integer
     * java.lang.Long#TYPE == long
     * java.lang.Float#TYPE == float
     * java.lang.Double#TYPE == double
     * java.lang.Void#TYPE == void
     */
    private static Class<?> parseClass(Class<?> type) {
        Class newType = type;
        final Map<Class, Class> classes = new HashMap<>(9);
        classes.put(boolean.class, Boolean.class);
        classes.put(char.class, Character.class);
        classes.put(byte.class, Byte.class);
        classes.put(short.class, Short.class);
        classes.put(int.class, Integer.class);
        classes.put(long.class, Long.class);
        classes.put(float.class, Float.class);
        classes.put(double.class, Double.class);
        classes.put(void.class, Void.class);
        return classes.getOrDefault(type, type);
    }
}

参考：https://blog.csdn.net/qq_36666651/article/details/81215221