Use a JAVA class to represent the "many-to-many" Relationship

The use of a class set not only represents a one-to-one relationship, but also represents a many-to-many relationship. For example, if a student can select multiple courses and multiple students can participate in one course, this is a typical multi-to-many relationship.

To complete this program, we should first define two categories: Student Information Student and Course information Course. There is a set in a student class to save all the courses. There must also be a set in the course class to save all the students.

Example: Define Student Class

 
 

  
  
PackageOrg.lxh.demo13.exe cdemo02;
  
  
ImportJava. util. ArrayList;
  
  
ImportJava. util. List;
  
  
Public ClassStudent {// Define the Student Category 
  
  
PrivateString name;// Define the name attribute 
  
  
Private IntAge;// Define the age attribute 
  
  
PrivateList <Course> allCourses;// Define a set to save all courses 
  
  
PublicStudent (){// No parameter structure 
  
  
This. AllCourses =NewArrayList <Course> ();// Instantiate the List set 
  
  
}
  
  
PublicStudent (String name,IntAge ){// Set the attribute content by constructing 
  
  
This();// Call construction without Parameters 
  
  
This. SetName (name );// Set the name attribute content 
  
  
This. SetAge (age );// Set the age attribute content 
  
  
}
  
  
PublicString getName (){// Obtain the name attribute 
  
  
ReturnName;
  
  
}
  
  
Public VoidSetName (String name ){// Set the name attribute 
  
  
This. Name = name;
  
  
}
  
  
Public IntGetAge (){// Obtain the age attribute 
  
  
ReturnAge;
  
  
}
  
  
Public VoidSetAge (IntAge ){// Set the age attribute 
  
  
This. Age = age;
  
  
}
  
  
PublicList <Course> getAllCourses (){// Obtain all courses 
  
  
ReturnAllCourses;
  
  
}
  
  
PublicString toString (){// Override the toString () method 
  
  
Return