[代码解析005] 关于一次bug排查解析 | new出一个对象其属性默认值是？

0、问题描述

子单据更新操作，单据状态更新，更新后单号变为0，经过排查发现更新操作代码中int类型单据号字段更新时未设置值。

1、代码片段

private int rowNum;

        // 子单据状态更新
        List<OutboundOrderDetails> updateOutboundOrderDetailsList = Lists.newArrayList();
        outboundOrderDetailsList.forEach(val -> {
            OutboundOrderDetails updateEntity = new OutboundDetailVO();
            updateEntity.setId(val.getId());
            updateEntity.setStatus(OutboundOrderDetails.STATUS_LOCK);
            updateEntity.preUpdate();
            updateOutboundOrderDetailsList.add(updateEntity);
        });
        outboundOrderDetailsService.updateBatchById(updateOutboundOrderDetailsList);

新增 updateEntity.setRowNum(val.getRowNum());

        // 子单据状态更新
        List<OutboundOrderDetails> updateOutboundOrderDetailsList = Lists.newArrayList();
        outboundOrderDetailsList.forEach(val -> {
            OutboundOrderDetails updateEntity = new OutboundDetailVO();
            updateEntity.setId(val.getId());
            updateEntity.setStatus(OutboundOrderDetails.STATUS_LOCK);
            updateEntity.setRowNum(val.getRowNum());
            updateEntity.preUpdate();
            updateOutboundOrderDetailsList.add(updateEntity);
        });
        outboundOrderDetailsService.updateBatchById(updateOutboundOrderDetailsList);

2、涉及知识点

Java基础，int类型默认值为0