### Error querying database. Cause: java.lang.IllegalArgumentException: Mapped Statements collectio

### Error querying database.  Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.domain.StudentMappper.selectCountStudent

### Cause: java.lang.IllegalArgumentException: Mapped Statements collection does not contain value for com.domain.StudentMappper.selectCountStudent

 

Mybatis中的xml文件是这样子写的

<!-- 查找列表总数 -->

 <select id="Count" resultType="int">

   select count(1) from student;

 </select> 

 

最好返回类型不能是int，用int就会报以上类型的错，改用为HashMap

@Override

public HashMap<String, String> selectCount() {

//int a = 0 ;

/*Count c=new CountImp();

Connection conn;

try {

try {

Class.forName("com.mysql.jdbc.Driver");

} catch (ClassNotFoundException e) {

// TODO Auto-generated catch block

e.printStackTrace();

}

conn = DriverManager.getConnection("jdbc:mysql://localhost:3306/db_database11","root","123456");

a=c.selectCount(conn);

} catch (SQLException e) {

e.printStackTrace();

}*/

    SqlSession session=sqlSessionFactory.openSession();

   /* a=session.selectOne("com.domain.StudentMappper.Count");*/

    HashMap<String, String> map=new HashMap<String, String>();

    String a=String.valueOf(session.selectOne("com.domain.StudentMapper.Count"));

    map.put("a", a);

/*a=session.selectMap("map", "com.domain.StudentMappper.selectCountStudent");*/

    return  map;

}