MYBATIS：使用动态查询比较字符串值

Question

我正在使用MyBatis映射一些需要比较string参数(mystring)的查询。

<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>

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'

以这种方式进行的string比较气味难闻。不幸的是，这是数据库建模的方式。

MyBatis版本:3.2.2

Answer 1

用MyBatis 3.2.8测试

<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>

请注意test周围的单引号和de常量值周围的双引号。诀窍是用你能看到的等式。