java collection addAll 操作需要非空判断

偏执的太偏执、 2023-06-22 03:18 18阅读 0赞

List<String> result  ;
            Set<String>  setResult = new HashSet<>();
            days.stream().forEach(t->{
                Set<String> set =(Set<String> ) redisTemplate.opsForHash().get(Contants.report3_monodb_tenentIds_day, t);
                setResult.addAll(set);
            });

如上面一段代码 addAll操作时候可能会抛出空指针

看下set的这个方法

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list接口也一样

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0FsYmVydEZseQ_size_16_color_FFFFFF_t_70 1][]

list的一个实现类 如下

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L0FsYmVydEZseQ_size_16_color_FFFFFF_t_70 2][]

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