Many-to-many mapping relationships in Java

Many pairs of mappings can be demonstrated with students and courses. One student can choose multiple courses, and one course corresponds to multiple students.

Defining student Classes

classstu{PrivateString name; PrivateString num; Privatecourse[] Course;  PublicStu () {} PublicStu (String name,string num) { This. Name =name;  This. num =num; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     PublicString Getnum () {returnnum; }     Public voidsetnum (String num) { This. num =num; }     Publiccourse[] GetCourse () {returncourse; }     Public voidsetcourse (course[] Course) { This. course =course; }     PublicString GetInfo () {return"Name:" +name+ "Study No.:" +num; }}

Defining Course Classes

classcourse{PrivateString name; Privatestu[] Stu;  PublicCourse () {} PublicCourse (String name) { This. Name =name; }     PublicString GetName () {returnname; }     Public voidsetName (String name) { This. Name =name; }     Publicstu[] Getstu () {returnStu; }     Public voidSetstu (stu[] Stu) { This. Stu =Stu; }     PublicString GetInfo () {return"Course:" +name; }        }

In the Main method test

First, the Stu and course objects are defined, each with three

        New Stu ("Zhang San", "001");         New Stu ("John Doe", "002");         New Stu ("Harry", "003");                 New Course ("Java");         New Course ("PHP");         New Course ("Python");

Set each other's relationships, each object has multiple objects corresponding to

        // setting up the relationship between        students and courses S1.setcourse (new  course[]{c1,c2});        S2.setcourse (new  course[]{c1,c3});        S3.setcourse (new  course[]{c2,c3});                 // The relationship between        the corresponding curriculum and the students C1.setstu (new  stu[]{s1,s2});        C2.setstu (new  stu[]{s1,s3});        C3.setstu (new stu[]{s2,s3});

Access to course information according to the student

        System.out.println (S1.getinfo () + "class selected by students");          for (int i=0; i<s1.getcourse (). length; i++) {            System.out.println (S1.getcourse () [I].getinfo ());        }

Run

Access to student information according to the course

        System.out.println (C2.getinfo () + "Select Student information for this course");          for (int i=0; I<c2.getstu (). length; i++) {            System.out.println (C2.getstu () [I].getinfo ());        }

Run

Many-to-many mapping relationships in Java