526互联

element cannot be mapped to a null key的解决方法

发布时间 2023-10-31 12:06:38作者: (Play)

目录

报错：

  1. 日志
ERROR [o.a.c.c.C.[.[.[/sa].[dispatcherServlet]] - Servlet.service() for servlet [dispatcherServlet] in context with path [/sa] threw exception [Request processing failed; nested exception is java.lang.NullPointerException: element cannot be mapped to a null key] with root cause

java.lang.NullPointerException: element cannot be mapped to a null key

分析

  1. 简单来说，要加一个非空的过滤

解决方案

  1. 代码
// 原代码：
Map<String, List<Device>> deviceMap = deviceList.stream().collect(Collectors.groupingBy(Device::getIp));

// 增加一个非空判断
Map<String, List<Device>> deviceMap = deviceList.stream()
  .filter(item-> StringUtils.isNotBlank(item.getIp())).collect(Collectors.groupingBy(Device::getIp));
  1. 就解决了
  • 需要注意其他的地方会不会影响到