SpringBoot中使用泛型&反射进行多表数据同步

1.业务描述

一次开发中，遇到接收多个表的数据，并批量插入数据库的需求，在此记录代码逻辑

2.实际开发

因为涉及到的表有很多，差不多4,50个，所以考虑使用泛型和反射来简化代码，提高开发效率

2.1 接收数据bean

样例中会精简部分代码


/**
 * 数据同步到保信--请求参数
 * Created by Youdmeng on 2019/6/4 0004.
 */
@Data
public class SaveToBaoxin {

    private String syncId;

    /**
     * 审核信息表
     */
    @Valid
    private List<CheckInfoEO> checkInfoEOList;

    /**
     * 组织机构表
     */
    private List<OrgInfoEO> orgInfoEOList;
}

2.2 取出个属性的列表对象

使用反射依次获取每组数据，

因为每组数据的类型不尽相同，所有使用泛型T来接收

private void dataSave(SaveToBaoxin saveToBaoxin) {
      List<SyncSuccessItemEO> successItemEOS = new ArrayList<>();
      syncDate = new Date();
      Class cls = saveToBaoxin.getClass();
      Field[] fields = cls.getDeclaredFields();

      for (Field field : fields) {
          if (StringUtils.equals(field.getName(), "syncId")) {
              continue;
          }
          field.setAccessible(true);
          Object object = ReflectionUtils.getFieldValue(saveToBaoxin, field.getName());
          List<T> list = (List<T>) object;
          save(list, successItemEOS);
      }
      try {
          baoXinDao.insertSuccessItemList(successItemEOS);
      } catch (Exception e) {
          logger.error("成功数据记录存储失败", e);
          //手动回滚事务
          TransactionAspectSupport.currentTransactionStatus().setRollbackOnly();
      }
}

2.3 核心保存代码

private <T> void save(List<T> list, List<SyncSuccessItemEO> successItemEOS) {

    List<String> checkInfoEOKeyList = new ArrayList<>();
    String table = null;
    String tableDesc = "";
    String dataDesc = "";//审核信息表
    for (T t : list) {
        Class<?> dataBean = t.getClass();
        try {
            table = SyncTableInfoEnums.getByLowerTableName(t.getClass().getSimpleName()).getTable();
            tableDesc = SyncTableInfoEnums.getByLowerTableName(t.getClass().getSimpleName()).getTableDesc();
//            dataDesc = t.getService() + "数据主键:" + checkInfoEO.getKeyId();
            if (null == ReflectionUtils.getFieldValue(t, "id") || null == ReflectionUtils.getFieldValue(t, "systemId")) {
                logger.error("|数据同步失败| " + " [" + table + "] [" + tableDesc + "] [" + dataDesc + "] [缺失数据主键]");
                syncLogService.errorLog(t, table, tableDesc, dataDesc, "缺失数据主键");
            } else {
                ReflectionUtils.setFieldValue(t, "syncFlag", 2);
                Class<?> syncDao = Class.forName("com.adc.da.manual.dao.manage.BaoxinSyncDao");
                try {
                    ReflectionUtils
                            .invokeMethod(sqlSession.getMapper(syncDao), "insert" + StringBuiltifer.formateClassName(table) + "EO", dataBean, t);
                } catch (Exception e) {
                    if (e.getCause() instanceof DuplicateKeyException) {
                        logger.info("主键已存在,进行数据更新");
                        ReflectionUtils
                                .invokeMethod(
                                        sqlSession.getMapper(syncDao),
                                        "updateByPrimaryKey" + StringBuiltifer.formateClassName(table) + "EO",
                                        dataBean,
                                        t);
                    }else {
                        throw e;
                    }
                }
            }
            checkInfoEOKeyList.add(ReflectionUtils.getFieldValue(t, "id") + "");
        } catch (Exception e) {
            logger.error("|数据同步失败| " + " [" + table + "] [" + tableDesc + "] [" + dataDesc + "] [" + e.getMessage() + "]", e);
            syncLogService.errorLog(t, table, tableDesc, dataDesc, e.getMessage());
        }

    }
    successItemEOS.add(putSuccessItem(table, checkInfoEOKeyList));
}

代码解析：
Class<?> syncDao = Class.forName("com.adc.da.manual.dao.manage.BaoxinSyncDao") 之前的部分，是取出数据，并根据业务逻辑进行校验，
本段代码，是获取要存储数据的dao层接口

@Repository
public interface BaoxinSyncDao {

    void insertcheckInfoEO(CheckInfoEO checkInfoEO);
    void insertorgInfoEO (OrgInfoEO orgInfoEO);

}

核心插入代码：

ReflectionUtils.invokeMethod(sqlSession.getMapper(syncDao), "insert" + StringBuiltifer.formateClassName(table) + "EO", dataBean, t);

本段代码等同于：

Method method = syncDao.getDeclaredMethod("insertcheckInfoEO", new Class[] { List.class });
method.invoke(sqlSession.getMapper(syncDao),t);

在开发过程中，我们会遇到需要使用使用反射来规范化批量操作的情况，但是当我们直接操作对应dao时，是不对的，我们需要反射sqlSession，来获取dao层控制权

2.4 反射工具类ReflectionUtils

/**
 * 反射工具类.
 * <p>
 * 提供访问私有变量,获取泛型类型Class, 提取集合中元素的属性, 转换字符串到对象等Util函数.
 */
public class ReflectionUtils {

    private static final Logger logger = LoggerFactory.getLogger(ReflectionUtils.class);

    /**
     * 调用Getter方法.
     */
    public static Object invokeGetterMethod(Object obj, String propertyName) {
        String getterMethodName = "get" + StringUtils.capitalize(propertyName);
        return invokeMethod(obj, getterMethodName, null, new Object[] {});
    }

    /**
     * 调用Setter方法.使用value的Class来查找Setter方法.
     */
    public static void invokeSetterMethod(Object obj, String propertyName, Object value) {
        invokeSetterMethod(obj, propertyName, value, null);
    }

    /**
     * 调用Setter方法.
     *
     * @param propertyType 用于查找Setter方法,为空时使用value的Class替代.
     */
    public static void invokeSetterMethod(Object obj, String propertyName, Object value, Class<?> propertyType) {
        Class<?> type = propertyType != null ? propertyType : value.getClass();
        String setterMethodName = "set" + StringUtils.capitalize(propertyName);
        invokeMethod(obj, setterMethodName, type, new Object[] { value });
    }

    /**
     * 直接读取对象属性值, 无视private/protected修饰符, 不经过getter函数.
     */
    public static Object getFieldValue(final Object obj, final String fieldName) {
        Field field = getAccessibleField(obj, fieldName);

        if (field == null) {
            throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
        }

        Object result = null;
        try {
            result = field.get(obj);
        } catch (IllegalAccessException e) {
            logger.error("不可能抛出的异常{}", e.getMessage());
        }
        return result;
    }

    /**
     * 直接设置对象属性值, 无视private/protected修饰符, 不经过setter函数.
     */
    public static void setFieldValue(final Object obj, final String fieldName, final Object value) {
        Field field = getAccessibleField(obj, fieldName);

        if (field == null) {
            throw new IllegalArgumentException("Could not find field [" + fieldName + "] on target [" + obj + "]");
        }

        try {
            field.set(obj, value);
        } catch (IllegalAccessException e) {
            logger.error("不可能抛出的异常:{}", e.getMessage());
        }
    }

    /**
     * 循环向上转型, 获取对象的DeclaredField,     并强制设置为可访问.
     * <p>
     * 如向上转型到Object仍无法找到, 返回null.
     */
    public static Field getAccessibleField(final Object obj, final String fieldName) {
        Assert.notNull(obj, "object不能为空");
        Assert.hasText(fieldName, "fieldName");
        for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
            try {
                Field field = superClass.getDeclaredField(fieldName);
                field.setAccessible(true);
                return field;
            } catch (NoSuchFieldException e) {//NOSONAR
                // Field不在当前类定义,继续向上转型
            }
        }
        return null;
    }

    /**
     * 直接调用对象方法, 无视private/protected修饰符.
     * 用于一次性调用的情况.
     */
    public static Object invokeMethod(final Object obj, final String methodName, final Class<?> tClass, final Object args) {
        Method method = getAccessibleMethod(obj, methodName, tClass);
        if (method == null) {
            throw new IllegalArgumentException("Could not find method [" + methodName + "] on target [" + obj + "]");
        }

        try {
            return method.invoke(obj, args);
        } catch (Exception e) {
            throw convertReflectionExceptionToUnchecked(e);
        }
    }

    /**
     * 循环向上转型, 获取对象的DeclaredMethod,并强制设置为可访问.
     * 如向上转型到Object仍无法找到, 返回null.
     * <p>
     * 用于方法需要被多次调用的情况. 先使用本函数先取得Method,然后调用Method.invoke(Object obj, Object... args)
     */
    public static Method getAccessibleMethod(final Object obj, final String methodName, final Class<?> tClass) {

        Assert.notNull(obj, "object不能为空");

        for (Class<?> superClass = obj.getClass(); superClass != Object.class; superClass = superClass.getSuperclass()) {
            try {
                Method method = superClass.getDeclaredMethod(methodName, new Class[] { tClass });

                method.setAccessible(true);

                return method;

            } catch (NoSuchMethodException e) {//NOSONAR
                // Method不在当前类定义,继续向上转型
            }
        }
        return null;
    }

    /**
     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.
     * 如无法找到, 返回Object.class.
     * eg.
     * public UserDao extends HibernateDao<User>
     *
     * @param clazz The class to introspect
     * @return the first generic declaration, or Object.class if cannot be determined
     */
    @SuppressWarnings({ "unchecked", "rawtypes" })
    public static <T> Class<T> getSuperClassGenricType(final Class clazz) {
        return getSuperClassGenricType(clazz, 0);
    }

    /**
     * 通过反射, 获得Class定义中声明的父类的泛型参数的类型.
     * 如无法找到, 返回Object.class.
     * <p>
     * 如public UserDao extends HibernateDao<User,Long>
     *
     * @param clazz clazz The class to introspect
     * @param index the Index of the generic ddeclaration,start from 0.
     * @return the index generic declaration, or Object.class if cannot be determined
     */
    @SuppressWarnings("rawtypes")
    public static Class getSuperClassGenricType(final Class clazz, final int index) {

        Type genType = clazz.getGenericSuperclass();

        if (!(genType instanceof ParameterizedType)) {
            logger.warn(clazz.getSimpleName() + "'s superclass not ParameterizedType");
            return Object.class;
        }

        Type[] params = ((ParameterizedType) genType).getActualTypeArguments();

        if (index >= params.length || index < 0) {
            logger.warn("Index: " + index + ", Size of " + clazz.getSimpleName() + "'s Parameterized Type: "
                    + params.length);
            return Object.class;
        }
        if (!(params[index] instanceof Class)) {
            logger.warn(clazz.getSimpleName() + " not set the actual class on superclass generic parameter");
            return Object.class;
        }

        return (Class) params[index];
    }

    /**
     * 将反射时的checked exception转换为unchecked exception.
     */
    public static RuntimeException convertReflectionExceptionToUnchecked(Exception e) {
        if (e instanceof IllegalAccessException || e instanceof IllegalArgumentException
                || e instanceof NoSuchMethodException) {
            return new IllegalArgumentException("Reflection Exception.", e);
        } else if (e instanceof InvocationTargetException) {
            return new RuntimeException("Reflection Exception.", ((InvocationTargetException) e).getTargetException());
        } else if (e instanceof RuntimeException) {
            return (RuntimeException) e;
        }
        return new RuntimeException("Unexpected Checked Exception.", e);
    }
}

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