How to get a specific Object from HashMap in MyBatis foreach?

Question

How can I get a specific object in a MyBatis foreach loop? I have written the following code:

<select id="getResult" resultMap="myResultMap" parameterType="java.util.HashMap">

    SELECT a.myselectfield_1, a.myselectfield_2                      
    FROM   ${mySchema}.test_a a    
    WHERE  a.field_x = 007
     AND   a.test_b IN 
             <foreach item="item" index="index" collection="#{map.get('myItems')}" open="(" separator="," close=")">
                #{item}         
            </foreach>
    ORDER BY a.myselectfield_1

</select>

This is the Java HashMap, which is relevant for the SQL Statement:

HashMap<String, Object> myMap = new HashMap<String, Object>();
myMap.put("mySchema", mySchema);
myMap.put("myItems", myArrayList);

I get the following error message:

Error querying database. Cause: java.lang.NullPointerException: target is null for method get

How can I read a specific value from a Java HashMap in MyBatis foreach? I´m using Version 1.1.1

Answer 1

您不需要使用get方法来访问map元素，只需在foreach标记中编写collection =“ myItems”或collection =“ map.myItems”即可，具体取决于您定义映射器接口的方式（后者假设您使用了@Param（“ map”）注释）。

Answer 2

you should be use $ replace # in foreach.

more information can see:

Mybatis foreach collection is a list in a map-parameter

MyBatis Issue with IN Condition <foreach with List inside a Map