Hibernate one-to-many many-to-one 双向关联

Hibernate one-to-many many-to-one 双向关联，设置多的一方维护关联关系，在指定one-to-many 的同时指定mappedBy 

例如：

public class ClassRoom(){

private string roomName;

@one-to-many(mappedBy="classRoomId")

private Set<Student> students = new HashSet<Student>();

}

public class Student(){

private string studentName;

@many-to-one

@JoinColumn(name="classRoomId")

private Set<Student> students = new HashSet<Student>();

}

设置一的一方维护关联关系，则必须取掉mappedBy,同时在多的一方设置@JoinColumn的insertable和updatable设置为false，

若不想产生中间表，则必须在一得一方指定@JoinColumn（指定多的一方的外键）：

public class ClassRoom(){

private string roomName;

@one-to-many

@JoinColumn(name="classRoomId")

private Set<Student> students = new HashSet<Student>();

}

public class Student(){

private string studentName;

@many-to-one

@JoinColumn(name="classRoomId", insertable=false,updatable = false)//注意是updatable 

private Set<Student> students = new HashSet<Student>();

}