Map 的 merge 方法

Map 的 merge 方法

文章目录

• Map 的 merge 方法
• • • • 1、简介
      • 2、说明
      • 3、使用
      • 4、场景
      • 5、对象归并

Map 的 merge 方法

1、简介

If the specified key is not already associated with a value or is associated with null, associates it with the given non-null value. Otherwise, replaces the associated value with the results of the given remapping function, or removes if the result is null. This method may be of use when combining multiple mapped values for a key. For example, to either create or append a String msg to a value (key, msg, String::concat)If