使用Mybatis 如何实现多对一或一对多的关联查询

package com.model;import java.util.Date;public class Student {  private Integer sno;  private String sname;  private String ssex;  private Integer sclass;  private StudentMajor studentmajor;  public Student() {    super();  }  public Student(Integer sno, String sname, String ssex, Integer sclass, StudentMajor studentmajor) {    super();    this.sno = sno;    this.sname = sname;    this.ssex = ssex;    this.sclass = sclass;    this.studentmajor = studentmajor;  }  public StudentMajor getStudentmajor() {    return studentmajor;  }  public void setStudentmajor(StudentMajor studentmajor) {    this.studentmajor = studentmajor;  }  public Integer getSno() {    return sno;  }  public void setSno(Integer sno) {    this.sno = sno;  }  public String getSname() {    return sname;  }  public void setSname(String sname) {    this.sname = sname;  }  public String getSsex() {    return ssex;  }  public void setSsex(String ssex) {    this.ssex = ssex;  }  @Override  public String toString() {    return "Student [sno=" + sno + ", sname=" + sname + ", ssex=" + ssex + ", sclass=" + sclass + ", studentmajor="        + studentmajor + "]";  }  public Integer getSclass() {    return sclass;  }  public void setSclass(Integer sclass) {    this.sclass = sclass;  }}