这个异常是什么原因。

这个错误是什么原因。。。
错误展示：java.lang.Exception: Method getUserList should have no parameters
test：
public class Usertest {
private static SqlSessionFactory sqlSessionFactory;
private static Reader reader;

static{
try{
reader=Resources.getResourceAsReader("Configuration.xml");
sqlSessionFactory=new SqlSessionFactoryBuilder().build(reader);
}catch(Exception e){
e.printStackTrace();
}
}
public static SqlSessionFactory getSession() {
return sqlSessionFactory;
}
@Test
public void getUserList(String userName){
SqlSession session=sqlSessionFactory.openSession();
try{
IUserOperation userOperation=session.getMapper(IUserOperation.class);
List<User> users=userOperation.selectUsers(userName);
for(User user:users){
System.out.println(user.getId()+""+user.getUserName()+""+user.getUserAddress());
}
}finally{
session.close();
}
}
}

configuration .xml

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE configuration PUBLIC "-//mybatis.org//DTD Config 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-config.dtd">
<configuration>
<typeAliases>
<typeAlias alias="User" type="com.yihaomen.mybatis.model.User"/>
</typeAliases>
<environments default="development">
<environment id="development">
<transactionManager type="JDBC"/>
<dataSource type="POOLED">
<property name="driver" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://192.168.0.250:3306/Wong"/>
<property name="username" value="root"/>
<property name="password" value=""/>
</dataSource>
</environment>
</environments>
<mappers>
<mapper resource="com/yihaomen/mybatis/model/User.xml"/>
</mappers>
</configuration>

User.xml

<?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">

<mapper namespace="com.yihaomen.mybatis.inter.IUserOperation">
<!-- 为了返回list类型而定义的returnMap-->
<resultMap type="User" id="resultListUser">
<id column="id" property="id"/>
<result column="userName" property="userName"/>
<result column="userAge" property="userAge"/>
<result column="userAddress" property="userAddress"/>
</resultMap>
    <select id="selectUserByID" parameterType="int" resultType="User">
        select * from user where id = #{id}
    </select>
<!-- 返回LIST的select语句。。注意resultMap的值是指向前面定义好的 -->
<select id="selectUsers" parameterType="String" resultMap="resultListUser">
select * from user where userName = #{userName}
</select>
</mapper>

------解决思路----------------------
去掉参数看看，
public void getUserList(  ){