mybatis高级映射一对一、一对多、多对多

一对一用assosiation用javaType

多对多用的是collection,用的是ofType

一对一

在Cunstomer类中加入Orders orders类型的属性并生产get、set方法

一对多

 
    
     
     
     
     
    
          
          
    
  
collection property="orders" ofType="com.yc.m.Orders">
          
          
    
  

在Cunstomer类中加入List orders类型的属性并生产get、set方法

多对多

public class Course {  
            private Integer id;  
            private String courseCode; // 课程编号  
            private String courseName;// 课程名称  
            private List students;// 选课学生  
           // get/set  
            public Course() {}  
        public Course(Integer id, String courseCode, String courseName) {  
            super();  
            this.id = id;  
            this.courseCode = courseCode;  
            this.courseName = courseName;  
        }  
        public Course(Integer id, String courseCode, String courseName,  
                List students) {  
            this.id = id;  
            this.courseCode = courseCode;  
            this.courseName = courseName;  
            this.students = students;  
        }  
        public Integer getId() {  
            return id;  
        }  
        public void setId(Integer id) {  
            this.id = id;  
        }  
        public String getCourseCode() {  
            return courseCode;  
        }  
        public void setCourseCode(String courseCode) {  
            this.courseCode = courseCode;  
        }  
        public String getCourseName() {  
            return courseName;  
        }  
        public void setCourseName(String courseName) {  
            this.courseName = courseName;  
        }  
        public List getStudents() {  
            return students;  
        }  
        public void setStudents(List students) {  
            this.students = students;  
        }  
        @Override  
        public String toString() {  
            return "Course [id=" + id + ", courseCode=" + courseCode  
                    + ", courseName=" + courseName + ", students=" + students  
                    + "]";  
        }  
}   Course {  
            private Integer id;  
            private String courseCode; // 课程编号  
            private String courseName;// 课程名称  
            private List students;// 选课学生  
           // get/set  
            public Course() {}  
        public Course(Integer id, String courseCode, String courseName) {  
            super();  
            this.id = id;  
            this.courseCode = courseCode;  
            this.courseName = courseName;  
        }  
        public Course(Integer id, String courseCode, String courseName,  
                List students) {  
            this.id = id;  
            this.courseCode = courseCode;  
            this.courseName = courseName;  
            this.students = students;  
        }  
        public Integer getId() {  
            return id;  
        }  
        public void setId(Integer id) {  
            this.id = id;  
        }  
        public String getCourseCode() {  
            return courseCode;  
        }  
        public void setCourseCode(String courseCode) {  
            this.courseCode = courseCode;  
        }  
        public String getCourseName() {  
            return courseName;  
        }  
        public void setCourseName(String courseName) {  
            this.courseName = courseName;  
        }  
        public List getStudents() {  
            return students;  
        }  
        public void setStudents(List students) {  
            this.students = students;  
        }  
        @Override  
        public String toString() {  
            return "Course [id=" + id + ", courseCode=" + courseCode  
                    + ", courseName=" + courseName + ", students=" + students  
                    + "]";  
        }  
}   

public class Student {  
            private Integer id;  
            private String name; // 姓名  
            private String gender; // 性别  
            private String major; // 专业  
            private String grade; // 年级  
            private List courses;// 所选的课程  
        public Student(Integer id, String name, String gender,String major, String grade, List courses) {  
                super();  
                this.id = id;  
                this.name = name;  
                this.gender = gender;  
                this.major = major;  
                this.grade = grade;  
                this.courses = courses;  
            }  
        public Student(Integer id, String name, String gender, String major,  
                String grade) {  
            super();  
            this.id = id;  
            this.name = name;  
            this.gender = gender;  
            this.major = major;  
            this.grade = grade;  
        }  
        public Student() {  
            super();  
        }  
        public Integer getId() {  
            return id;  
        }  
        public void setId(Integer id) {  
            this.id = id;  
        }  
        public String getName() {  
            return name;  
        }  
        public void setName(String name) {  
            this.name = name;  
        }  
        public String getGender() {  
            return gender;  
        }  
        public void setGender(String gender) {  
            this.gender = gender;  
        }  
        public String getMajor() {  
            return major;  
        }  
        public void setMajor(String major) {  
            this.major = major;  
        }  
        public String getGrade() {  
            return grade;  
        }  
        public void setGrade(String grade) {  
            this.grade = grade;  
        }  
        public List getCourses() {  
            return courses;  
        }  
        public void setCourses(List courses) {  
            this.courses = courses;  
        }  
        @Override  
        public String toString() {  
            return "Student [id=" + id + ", name=" + name + ", gender="  
                    + gender + ", major=" + major + ", grade=" + grade  
                    + ", courses=" + courses + "]";  
        }  
              
        }  Student {  
            private Integer id;  
            private String name; // 姓名  
            private String gender; // 性别  
            private String major; // 专业  
            private String grade; // 年级  
            private List courses;// 所选的课程  
        public Student(Integer id, String name, String gender,String major, String grade, List courses) {  
                super();  
                this.id = id;  
                this.name = name;  
                this.gender = gender;  
                this.major = major;  
                this.grade = grade;  
                this.courses = courses;  
            }  
        public Student(Integer id, String name, String gender, String major,  
                String grade) {  
            super();  
            this.id = id;  
            this.name = name;  
            this.gender = gender;  
            this.major = major;  
            this.grade = grade;  
        }  
        public Student() {  
            super();  
        }  
        public Integer getId() {  
            return id;  
        }  
        public void setId(Integer id) {  
            this.id = id;  
        }  
        public String getName() {  
            return name;  
        }  
        public void setName(String name) {  
            this.name = name;  
        }  
        public String getGender() {  
            return gender;  
        }  
        public void setGender(String gender) {  
            this.gender = gender;  
        }  
        public String getMajor() {  
            return major;  
        }  
        public void setMajor(String major) {  
            this.major = major;  
        }  
        public String getGrade() {  
            return grade;  
        }  
        public void setGrade(String grade) {  
            this.grade = grade;  
        }  
        public List getCourses() {  
            return courses;  
        }  
        public void setCourses(List courses) {  
            this.courses = courses;  
        }  
        @Override  
        public String toString() {  
            return "Student [id=" + id + ", name=" + name + ", gender="  
                    + gender + ", major=" + major + ", grade=" + grade  
                    + ", courses=" + courses + "]";  
        }  
              
        }  

 

  
       
          
              
              
              
              
              
          
          
          
              
          
          
          
              
              
              
          
          
          
            select s.id,s.name,s.gender,s.major,s.grade,c.id as cid,c.course_code,c.course_name,sc.id,sc.student_id,sc.course_id  
            from student s,course c,student_course sc  
            where    
            s.id=#{id}  
            and  
            s.id=sc.student_id    
            and    
            sc.course_id=c.id  
          collection property="courses" resultMap="CourseResult">  
          
          
          
              
              
              
          
          
          
            select s.id,s.name,s.gender,s.major,s.grade,c.id as cid,c.course_code,c.course_name,sc.id,sc.student_id,sc.course_id  
            from student s,course c,student_course sc  
            where    
            s.id=#{id}  
            and  
            s.id=sc.student_id    
            and    
            sc.course_id=c.id