记一次$jacocoData引起的bug

太过爱你忘了你带给我的痛 2023-01-11 01:21 473阅读 0赞

**bug描述:**

项目开发过程中, 遇到了一个奇怪的现象, 在测试环境去利用反射拿一个类的字段时, 发现拿到的field数组中多了一个奇怪的变量: $jacocoData, 它是一个boolean数组.

在开发环境中没有这个问题, 但是部署到测试环境之后有这个问题.

发现这个问题的缘由: 对接了一个第三方系统, 可能他们系统对于数据类型比较严格, 要求传的字段是规定的类型且不能为null. 然后部署到测试环境发现报错了,

报错内容: com.sensorsdata.analytics.javasdk.exceptions.InvalidArgumentException: The property 'groupBuy\_e\_$jacocoData' should be a basic type: Number, String, Date, Boolean, List<String>.

因为我们自己业务系统中要求字段前缀是以"groupBuy\_e\_"开头, 所以我利用反射写了个方法, 对字段属性名称进行拼接.

public class BeanToMapUtils {
        private static Logger LOGGER = LoggerFactory.getLogger(BeanToMapUtils.class);
        /**
         * 属性名前缀
         */
        private static final String PREFIX = "groupBuy_e_";
    
        /**
         * 将一个 JavaBean 对象转化为一个  Map
         *
         * @param bean 要转化的JavaBean 对象
         * @return 转化出来的  Map 对象
         * @throws IntrospectionException    如果分析类属性失败
         * @throws IllegalAccessException    如果实例化 JavaBean 失败
         * @throws InvocationTargetException 如果调用属性的 setter 方法失败
         */
        public static Map<String, Object> beanToMap(Object bean) {
            Class type = bean.getClass();
            Map<String, Object> returnMap = new HashMap<>(16);
            Field[] fieldArray = type.getDeclaredFields();
            for (Field field : fieldArray) {
                field.setAccessible(true);
                try {
                    Object value = field.get(bean);
                    if (ObjectUtils.isEmpty(value)) {
                        // 为空是设置默认值
                        if (field.getType().isInstance(new BigDecimal(0))) {
                            value = BigDecimal.ZERO;
                        }
                        if (field.getType().isInstance(new String())) {
                            value = "";
                        }
                        if (field.getType().isInstance(new Integer(0))) {
                            value = new Integer(0);
                        }
                        if (field.getType().isInstance(new Boolean(false))) {
                            value = new Boolean(false);
                        }
                    }
                    returnMap.put(PREFIX + field.getName(), value);
                } catch (Exception e) {
                    LOGGER.error("BeanToMapUtils beanToMap fail: {}", e);
                }
            }
            return returnMap;
        }
    }

莫名其妙多出这个$jacocoData属性, 技术菜鸟表示很懵逼.

于是开始了寻找解决方案之路.

首先我在网上看到一篇关于类似问题的博客: [https://zhanglijun1217.github.io/blog/2019/03/10/%E4%B8%80%E6%AC%A1%E6%8E%92%E6%9F%A5-jacocoData%E7%9A%84%E8%BF%87%E7%A8%8B/][https_zhanglijun1217.github.io_blog_2019_03_10_E4_B8_80_E6_AC_A1_E6_8E_92_E6_9F_A5-jacocoData_E7_9A_84_E8_BF_87_E7_A8_8B]

原来和JaCoco有关系, 对JaCoco了解不甚多, 只知道它是代码覆盖率工具. 了解了一下它的基本原理, 它使用的ASM技术修改字节码方法, 可以修改Jar文件、class文件字节码文件(详细可以参考博客[https://cloud.tencent.com/developer/article/1038055][https_cloud.tencent.com_developer_article_1038055])

JaCoco官网FAQ中有一条是关于$jacocoData的, 如下:

[https://www.eclemma.org/jacoco/trunk/doc/faq.html][https_www.eclemma.org_jacoco_trunk_doc_faq.html]

![20210126142921700.png][]

官方建议是修改代码, 忽略synthetic成员.

至于什么是synthetic, 你可以参考一下:[https://www.cnblogs.com/bethunebtj/p/7761596.html][https_www.cnblogs.com_bethunebtj_p_7761596.html] 和 [https://www.baeldung.com/java-synthetic][https_www.baeldung.com_java-synthetic]

*"Any constructs introduced by a Java compiler that do not have a corresponding construct in the source code must be marked as synthetic, except for default constructors, the class initialization method, and the values and valueOf methods of the Enum class."*

解决方案自然是忽略synthetic成员了, 可以用下面这个方法判断是否是synthetic field:

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NzcyNTE4_size_16_color_FFFFFF_t_70][]

所以BeanToMapUtils类加几行代码:

public class BeanToMapUtils {
        private static Logger LOGGER = LoggerFactory.getLogger(BeanToMapUtils.class);
        /**
         * 属性名前缀
         */
        private static final String PREFIX = "groupBuy_e_";
    
        /**
         * 将一个 JavaBean 对象转化为一个  Map
         *
         * @param bean 要转化的JavaBean 对象
         * @return 转化出来的  Map 对象
         * @throws IntrospectionException    如果分析类属性失败
         * @throws IllegalAccessException    如果实例化 JavaBean 失败
         * @throws InvocationTargetException 如果调用属性的 setter 方法失败
         */
        public static Map<String, Object> beanToMap(Object bean) {
            Class type = bean.getClass();
            Map<String, Object> returnMap = new HashMap<>(16);
            Field[] fieldArray = type.getDeclaredFields();
            for (Field field : fieldArray) {
                // 忽略synthetic成员
                if (field.isSynthetic()) {
                    continue;
                }
                field.setAccessible(true);
                try {
                    Object value = field.get(bean);
                    if (ObjectUtils.isEmpty(value)) {
                        // 为空是设置默认值
                        if (field.getType().isInstance(new BigDecimal(0))) {
                            value = BigDecimal.ZERO;
                        }
                        if (field.getType().isInstance(new String())) {
                            value = "";
                        }
                        if (field.getType().isInstance(new Integer(0))) {
                            value = new Integer(0);
                        }
                        if (field.getType().isInstance(new Boolean(false))) {
                            value = new Boolean(false);
                        }
                    }
                    returnMap.put(PREFIX + field.getName(), value);
                } catch (Exception e) {
                    LOGGER.error("BeanToMapUtils beanToMap fail: {}", e);
                }
            }
            return returnMap;
        }
    }

总结与反思:

**When your code uses reflection, please  ignore synthetic members. This is a good practice anyways as also the Java compiler creates synthetic members in certain situation.**

...... 以上仅供参考, 欢迎批评与指正!

参考:

[https://zhanglijun1217.github.io/blog/2019/03/10/%E4%B8%80%E6%AC%A1%E6%8E%92%E6%9F%A5-jacocoData%E7%9A%84%E8%BF%87%E7%A8%8B/][https_zhanglijun1217.github.io_blog_2019_03_10_E4_B8_80_E6_AC_A1_E6_8E_92_E6_9F_A5-jacocoData_E7_9A_84_E8_BF_87_E7_A8_8B]

[https://cloud.tencent.com/developer/article/1038055][https_cloud.tencent.com_developer_article_1038055]

[https://github.com/jacoco/jacoco/issues/168][https_github.com_jacoco_jacoco_issues_168]

[https://www.baeldung.com/java-synthetic][https_www.baeldung.com_java-synthetic]

[https://www.cnblogs.com/bethunebtj/p/7761596.html][https_www.cnblogs.com_bethunebtj_p_7761596.html]

[https_zhanglijun1217.github.io_blog_2019_03_10_E4_B8_80_E6_AC_A1_E6_8E_92_E6_9F_A5-jacocoData_E7_9A_84_E8_BF_87_E7_A8_8B]: https://zhanglijun1217.github.io/blog/2019/03/10/%E4%B8%80%E6%AC%A1%E6%8E%92%E6%9F%A5-jacocoData%E7%9A%84%E8%BF%87%E7%A8%8B/
[https_cloud.tencent.com_developer_article_1038055]: https://cloud.tencent.com/developer/article/1038055
[https_www.eclemma.org_jacoco_trunk_doc_faq.html]: https://www.eclemma.org/jacoco/trunk/doc/faq.html
[20210126142921700.png]: /images/20221119/864abcf4005247dc9a053ee4f454d29d.png
[https_www.cnblogs.com_bethunebtj_p_7761596.html]: https://www.cnblogs.com/bethunebtj/p/7761596.html
[https_www.baeldung.com_java-synthetic]: https://www.baeldung.com/java-synthetic
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L20wXzM3NzcyNTE4_size_16_color_FFFFFF_t_70]: /images/20221119/d113a903b57642b783c1cc24d67025d0.png
[https_github.com_jacoco_jacoco_issues_168]: https://github.com/jacoco/jacoco/issues/168