可以把这三个循环封装一下吗？

Question

XDM,可以把这三个循环封装一下吗？

 if (rowBefore == null && rowAfter != null) {
            jsonArrayAfter = JSON.parseArray(rowAfter);
            for (Object obj : jsonArrayAfter) {
                for (Map.Entry<String, Object> stringObjectEntry : ((JSONObject) obj).entrySet()) {
                    DifferenceOfFieldsVO fieldsVO = new DifferenceOfFieldsVO();
                    fieldsVO.setTableName(tableName);
                    fieldsVO.setId(id);
                    fieldsVO.setFieldName(stringObjectEntry.getKey());
                    fieldsVO.setFieldAfter(String.valueOf(stringObjectEntry.getValue()));
                    list.add(fieldsVO);
                }
            }
        } else if (rowBefore != null && rowAfter == null) {//delete
            jsonArrayBefore = JSON.parseArray(rowBefore);
            for (Object obj : jsonArrayBefore) {
                for (Map.Entry<String, Object> stringObjectEntry : ((JSONObject) obj).entrySet()) {
                    DifferenceOfFieldsVO fieldsVO = new DifferenceOfFieldsVO();
                    fieldsVO.setTableName(tableName);
                    fieldsVO.setId(id);
                    fieldsVO.setFieldName(stringObjectEntry.getKey());
                    fieldsVO.setFieldBefore(String.valueOf(stringObjectEntry.getValue()));
                    list.add(fieldsVO);
                }
            }
        } else if (rowBefore != null && rowAfter != null) {//update
            jsonArrayBefore = JSON.parseArray(rowBefore);
            for (int i = 0; i < jsonArrayBefore.size(); i++) {
                JSONObject beforeObject =   (JSONObject)jsonArrayBefore.get(i);
                JSONObject afterObject =   (JSONObject)jsonArrayBefore.get(i);
                for (Map.Entry<String, Object> beforeEntry : beforeObject.entrySet())  {
                    DifferenceOfFieldsVO fieldsVO = new DifferenceOfFieldsVO();
                    fieldsVO.setTableName(tableName);
                    fieldsVO.setId(id);
                    fieldsVO.setFieldName(beforeEntry.getKey());
                    fieldsVO.setFieldBefore(String.valueOf(beforeEntry.getValue()));
                    fieldsVO.setFieldAfter(String.valueOf( afterObject.get(beforeEntry.getKey())));
                    list.add(fieldsVO);
                }
            }
        }

Answer 1

这段代码中有一部分重复的代码，可以封装成一个单独的方法来提高代码的可读性和可维护性。你可以创建一个方法，如processEntry，来处理这部分逻辑。

private void processEntry(JSONObject obj, String tableName, String id, String after, List<DifferenceOfFieldsVO> list) {
    for (Map.Entry<String, Object> stringObjectEntry : obj.entrySet()) {
        DifferenceOfFieldsVO fieldsVO = new DifferenceOfFieldsVO();
        fieldsVO.setTableName(tableName);
        fieldsVO.setId(id);
        fieldsVO.setFieldName(stringObjectEntry.getKey());
        if (after != null) {
            fieldsVO.setFieldAfter(String.valueOf(stringObjectEntry.getValue()));
        } else {
            fieldsVO.setFieldBefore(String.valueOf(stringObjectEntry.getValue()));
        }
        list.add(fieldsVO);
    }
}

然后你可以在你的代码中调用这个方法：

if (rowBefore == null && rowAfter != null) {
    jsonArrayAfter = JSON.parseArray(rowAfter);
    for (Object obj : jsonArrayAfter) {
        processEntry((JSONObject) obj, tableName, id, "after", list);
    }
} else if (rowBefore != null && rowAfter == null) {
    jsonArrayBefore = JSON.parseArray(rowBefore);
    for (Object obj : jsonArrayBefore) {
        processEntry((JSONObject) obj, tableName, id, null, list);
    }
} else if (rowBefore != null && rowAfter != null) {
    jsonArrayBefore = JSON.parseArray(rowBefore);
    for (int i = 0; i < jsonArrayBefore.size(); i++) {
        JSONObject beforeObject = (JSONObject) jsonArrayBefore.get(i);
        JSONObject afterObject = (JSONObject) jsonArrayBefore.get(i);
        processEntry(beforeObject, tableName, id, null, list);
        processEntry(afterObject, tableName, id, "after", list);
    }
}

注意：在最后一个 else if 分支中，我分别对 beforeObject 和 afterObject 进行了处理。如果你的逻辑需要特别处理这两个对象，你可能需要调整这个部分的代码。