hibernate多对多双向关联

hibernate多对多双向关联

(1)Anotation

package com.bjsxt.hibernate;


import java.util.HashSet;
import java.util.Set;


import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.ManyToMany;


@Entity
public class Student {
private int id;
private String name;
private Set<Teacher> teachers = new HashSet<Teacher>();
@ManyToMany(mappedBy="students")
public Set<Teacher> getTeachers() {
return teachers;
}
public void setTeachers(Set<Teacher> teachers) {
this.teachers = teachers;
}
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
}

package com.bjsxt.hibernate;


import java.util.HashSet;
import java.util.Set;


import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.JoinColumn;
import javax.persistence.JoinTable;
import javax.persistence.ManyToMany;
import javax.persistence.OneToMany;
import javax.persistence.Table;


@Entity
public class Teacher {
private int id;
private String name;
private Set<Student> students = new HashSet<Student>();
@Id
@GeneratedValue
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}
@ManyToMany
@JoinTable(name="t_s",
joinColumns={@JoinColumn(name="teacher_id")},
inverseJoinColumns={@JoinColumn(name="student_id")}
)
public Set<Student> getStudents() {
return students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
}

(2)xml

--Student.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">


<hibernate-mapping>
<class name="com.bjsxt.hibernate.Student">
<id name="id">
<generator class="native"></generator>
</id>

<property name="name"></property>
<set name="teachers" table="t_s">
<key column="student_id"></key>
<many-to-many class="com.bjsxt.hibernate.Teacher" column="teacher_id"/>
</set>
    </class>

</hibernate-mapping>

--Teacher.hbm.xml

<?xml version="1.0"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">


<hibernate-mapping>
<class name="com.bjsxt.hibernate.Teacher">
<id name="id">
<generator class="native"></generator>
</id>

<property name="name"></property>
<set name="students" table="t_s">
<key column="teacher_id"></key>
<many-to-many class="com.bjsxt.hibernate.Student" column="student_id"/>
</set>
    </class>

</hibernate-mapping>