Spring / Mybatis映射中的范围变量

Question

I have a conversationScope.myVar="myValue" variable;

I would like to use it inside a mybatis map such as,

select col1, col1, conversationScope.myVar as ScopeVar
from table1;

desired result

col1  col2  ScopeVar

xxxx  xxxx   myValue

yyyy  yyyy   myValue

...

Answer 1

MyBatis does support dynamic SQL in the nature you need. The big trick, is to use ${variable} instead of #{variable}. Just be careful, it leaves you susceptible to SQL injection attacks. When using # MyBatis uses PreparedStatements to avoid SQL injection, and then

So take for example example, you had a Mapper interface with method.

ComplexObject selectSomeObject(@Param("columnName") String columnName);

Your SQL map could use the parameter in part of the actual select code.

ie

<select id="selectSomeObject" resultType="someObject"> 
    select t1.column as ${columnName}    
    from table1 t1
 </select>

If you need a global variable, check out this question. MyBatis - defining a global parameter