专业知识|Java 对两个list的对比操作工具类 list|对比|数据库|java

目前在项目中遇到如下的需求，在项目中有一个定时任务去统计数据，统计出来的数据会存入一张统计表A中，每次统计的时候需要去判断新旧统计数据（两个List），如果原来已经存在的数据进行更新，原来不存在的数据进行新增，原来存在但是新数据中不存在的数据进行删除。于是进行了架构设计，通过使用一个抽象类和一个新旧数据对比处理类来实现这一需求。
抽象类代码如下：

public abstract class HomeReportDataBuilder { /** * Render the hash code of operation. * * Example: (companyId_serviceId_operation_recordId).hashCode() * * * @param t * @return */ public String renderKey(T t) { return null; }/** * Render the hash code of operation. * * Example: (companyId_新旧数据对比处理类serviceId_operation_recordId).hashCode() * * * @param t * @return */ public String renderUpdateIbatis() { return null; }/** * Render the hash code of operation. * * Example: (companyId_serviceId_operation_recordId).hashCode() * * * @param t * @return */ public String renderAddIbatis() { return null; }/** * Render the hash code of operation. * * Example: (companyId_serviceId_operation_recordId).hashCode() * * * @param t * @return */ public String renderDeleteIbatis() { return null; } }

新旧数据对比处理类代码如下： 【专业知识|Java 对两个list的对比操作工具类】

public class HomeReportServiceImpl implements HomeReportService { protected BatchDao batchDao; public BatchDao getBatchDao() { return batchDao; } public void setBatchDao(BatchDao batchDao) { this.batchDao = batchDao; } public void dealData(Map currentData, List originalData, HomeReportDataBuilder dataBuilder) { List updateList = new ArrayList(); List addList = new ArrayList(); List deleteList = new ArrayList(); // separate currentData and originalData to updateList, addList and deleteListfor (T originalItem : originalData) { String key = dataBuilder.renderKey(originalItem); // this originalItem has data today, we will update data if (currentData.containsKey(key)) { T current = currentData.get(key); current.setId(originalItem.getId()); updateList.add(current); currentData.remove(key); } else { // if originalItem not exist in map, originalItem need to delete deleteList.add(originalItem); } }if (!currentData.isEmpty()) { // if map still has data, these data not exist in database, we should insert these data for (Entry entry : currentData.entrySet()) { addList.add(entry.getValue()); } }int i = 0; while (i < deleteList.size() && i < addList.size()) { T item = addList.get(i); item.setId(deleteList.get(i).getId()); updateList.add(item); i++; }addList = addList.subList(i, addList.size()); deleteList = deleteList.subList(i, deleteList.size()); batchDao.batchDataOperation(updateList, dataBuilder.renderUpdateIbatis()); batchDao.batchDataOperation(addList, dataBuilder.renderAddIbatis()); batchDao.batchDataOperation(deleteList, dataBuilder.renderDeleteIbatis()); }/** * @see cn.vobile.trackerspt.service.homereport.HomeReportService#dealData(java.util.List, java.util.List, cn.vobile.trackerspt.service.homereport.HomeReportDataBuilder) */ public void dealData(List currentData, List originalData, HomeReportDataBuilder dataBuilder) { Map map = new HashMap(); for (T data : currentData) { map.put(dataBuilder.renderKey(data), data); }dealData(map, originalData, dataBuilder); }}

* 考虑到每个实体的key值会由不同的数据表字段组成，并且每个调用的方法对应的数据表也是不同的，因此在实现两个List对比处理的时候，都要继承抽象类