Mybatis使用查询失败查询一直为空

<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN" "http://mybatis.org/dtd/mybatis-3-mapper.dtd">

<!-- 一般在查询时使用-->






<!-- 定义插入的sql语句，通过命名空间+id方式被定位 -->

insert into dept(dept_name,dept_address) values(#{deptName},#{deptAddress})

<update id="update" parameterType="Dept">
    update dept set dept_name=#{deptName},dept_address=#{deptAddress}
    where dept_id =#{deptId}
</update>

<delete id="delete" parameterType="Dept">
    delete from dept where dept_id=#{deptId}
</delete>
<select id="selectOne" parameterType="int" resultMap="deptResultMap"  >
    select * from dept where dept_id=#{deptId}  
</select>
<select id="selectList" parameterType="string" resultMap="deptResultMap">
    select * from dept where dept_address=#{deptAddress}
</select>

public class MyBatisUtil {
private static final ThreadLocal threadLocal = new ThreadLocal();

private static SqlSessionFactory sessionFactory;

private static String CONFIG_FILE_LOCATION ="myBatis-config.xml";

static {
    try {
        buildSessionFactory();
    } catch (Exception e) {
        System.err.println("%%%% Error Creating SessionFactory %%%%");
        e.printStackTrace();
    }
}
private MyBatisUtil() {
}

/**
 * Returns the ThreadLocal Session instance.  Lazy initialize
 * the <code>SessionFactory</code> if needed.
 *
 *  @return Session
 *  @throws Exception
 */
public static SqlSession getSession() throws Exception {
    SqlSession session = (SqlSession) threadLocal.get();

    if (session == null) {
        if (sessionFactory == null) {
            buildSessionFactory();
        }
        session = (sessionFactory != null) ? sessionFactory.openSession()
                : null;
        threadLocal.set(session);
    }

    return session;
}

/**
 *  build  session factory
 *
 */
public static void buildSessionFactory() {
    Reader reader=null;
    try {
        reader=Resources.getResourceAsReader(CONFIG_FILE_LOCATION);
        sessionFactory = new SqlSessionFactoryBuilder().build(reader);
    } catch (Exception e) {
        System.err.println("%%%% Error Creating SessionFactory %%%%");
        e.printStackTrace();
    }finally{
        try {
            reader.close();
        } catch (IOException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }
}

/**
 *  Close the single  session instance.
 *
 */
public static void closeSession(){
    SqlSession session = (SqlSession) threadLocal.get();
    threadLocal.set(null);

    if (session != null) {
        session.close();
    }
}

/**
 *  return session factory
 *
 */
public static SqlSessionFactory getSessionFactory() {
    return sessionFactory;
}

}

public Dept selectOne(int deptId) {
Dept dept = null;
SqlSession session = null;
try {
session = MyBatisUtil.getSession();
dept = (Dept)session.selectOne("cn.scau.cty.DeptMapper.selectOne", deptId);
} catch (Exception e) {
e.printStackTrace();
session.rollback();
}finally{
MyBatisUtil.closeSession();
}
return dept;
}

@Test
public void testSelectOne(){
    Dept dept = deptDaoImpl.selectOne(4);
    System.out.println("查询到的记录部门是"+dept);
}

查询到的记录 是null 求大神帮忙看下 谢谢了

上面没显示出来的是这个

deptResultMap你这个有定义么？有没有对应好。