How to resolve the error with empty list being passed into MyBatis?

In MyBatis, if an empty List is passed, it may result in a java.lang.NullPointerException exception. To address this issue, you can add some defensive programming logic in the code to handle an empty List.

Here is one possible solution:

1. Before calling the Mapper method, check if the List is empty. If it is empty, you can just return an empty result.

if (list == null || list.isEmpty()) {
    return new ArrayList<>(); // 返回一个空结果
}

1. for each

<foreach collection="list" item="item" open="WHERE" separator="," close="">
    <if test="list != null and !list.isEmpty()">
        column = #{item}
    </if>
</foreach>

By using the above method, you can avoid the occurrence of a NullPointerException when the input List is empty, and return an empty result.