MyBatis: compare String value using dynamic query

Question

I'm using MyBatis to map some queries where I need to compare a String argument (myString).

My Mapper interface is:

public Map<Integer, String> findSomething(@Param("myString") String myString);

My XML is as follow:

<select id="findSomething" parameterType="String" resultType="Map">
    SELECT column1 as key,
           column2 as value
    FROM my_table
    <where>
         <choose>
            <when test="myString == 'xxx'">
                column3 = 1
            </when>
            <when test="myString == 'yyy'">
                myColumn  = 2
            </when>
            <when test="myString == 'zzz'">
                myColumn  = 3
            </when>
        </choose>
    </where>
    ORDER BY value;
</select>

When I execute this statement the following error is throwed:

ERROR [stderr] Caused by: org.apache.ibatis.exceptions.PersistenceException: 
ERROR [stderr] ### Error querying database.  Cause: org.apache.ibatis.reflection.ReflectionException: There is no getter for property named 'myString' in 'class java.lang.String'

A String comparison made this way, smells bad. Unfortunately it was the way database was modeled.

MyBatis version: 3.2.2

Answer 1

Tested with MyBatis 3.2.8

<select id="findSomething" parameterType="String" resultType="Map">
    SELECT column1 as key,
           column2 as value
    FROM my_table
    <where>
         <choose>
            <when test='"xxx".equals(myString)'>
                column3 = 1
            </when>
            <when test='"yyy".equals(myString)'>
                myColumn  = 2
            </when>
            <when test='"zzz".equals(myString)'>
                myColumn  = 3
            </when>
        </choose>
    </where>
    ORDER BY value;
</select>

Note the single quotes around test and the double quotes around de constant values. The trick is to use equals as you can see.

Answer 2

Definitely I had to go through a complicated approach.

Changed mapper method signature:

public Map<Integer, String> findSomething(@Param("myPojo") MyPojo myPojo);

The XML must be:

<select id="findSomething" resultType="Map">
SELECT column1 as key,
       column2 as value
FROM my_table
<where>
     <choose>
        <when test="myPojo == 'xxx'">
            column3 = 1
        </when>
        <when test="myPojo == 'yyy'">
            myColumn  = 2
        </when>
        <when test="myPojo == 'zzz'">
            myColumn  = 3
        </when>
    </choose>
</where>
ORDER BY value;

Just don't forget, being a POJO, the parameter class must have it's respective getters and setters.