映射mybatis中的字符串列表

Question

我想使用mybatis来修改字符串列表。我正在使用以下代码，但是如下所示获取illegalArgument异常：

   javax.servlet.ServletException: org.mybatis.spring.MyBatisSystemException: SqlSession operation; nested exception is java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for java.lang.Object.toString
        org.apache.struts2.dispatcher.Dispatcher.serviceAction(Dispatcher.java:515)
        org.apache.struts2.dispatcher.FilterDispatcher.doFilter(FilterDispatcher.java:419)

Mybatis配置：

<select id="fetchIds" resultType="java.lang.String" >
        SELECT distinct ids 
        FROM abc.emp 
</select>

我的Dao方法是：

@Override
    public List<String> fetchIds() {
        System.out.println("Inside fetchIds");
        SqlSession session = null;
        List retrieveList = null;
        try{
         session = sqlSessionFactory.openSession();
         System.out.println("After session creation:"+session);
         retrieveList =  session.selectList("fetchIds");
        }finally{
            session.close();
        }

        return retrieveList;

    }

任何人都可以建议我们如何实现这一目标。

Answer 1

将List定义为List<String>。这里你的代码看起来像

<select id="fetchIds" resultType="string" >
        SELECT distinct ids 
        FROM abc.emp 
</select>

和Dao方法

@Override
    public List<String> fetchIds() {
        System.out.println("Inside fetchIds");
        SqlSession session = null;
        List<String> retrieveList = null;
        try{
         session = sqlSessionFactory.openSession();
         System.out.println("After session creation:"+session);
         retrieveList =  session.selectList("fetchIds");
        }finally{
            session.close();
        }

        return retrieveList;

    }

mapper interface.java文件的方法签名如下。

String[] fetchIds()throws Exception;