many2many 单向_单向的many2many-优快云博客

本文链接：https://blog.youkuaiyun.com/wgs396838895/article/details/8585214

本文介绍使用Hibernate实现多对多关系的两种方式：通过注解和XML配置。包括Student和Teacher实体类的设计，以及如何定义它们之间的关联。

@Entity
public class Student {
	private int id;
	private String name;
	public Student() {
		super();
		// TODO Auto-generated constructor stub
	}
	@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;
	}
}

@Entity
public class Teacher {
	private int id;
	private String name;
	private Set<Student> students=new HashSet<Student>();
	
	@ManyToMany
	@JoinTable(name="t_s",
			joinColumns=@JoinColumn(name="t_teacher"),
			inverseJoinColumns=@JoinColumn(name="t_student"))
	public Set<Student> getStudents() {
		return students;
	}

	public void setStudents(Set<Student> students) {
		this.students = students;
	}

	@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;
	}

	public Teacher() {
		super();
		// TODO Auto-generated constructor stub
	}
}

上面是 annocation的

接着是xml的

<hibernate-mapping package="com.sl.many2many">
	<class name="Student">
		<id name="id" column="s_id">
			<generator class="native" />
		</id>
		<property name="name" column="s_name"/>
	</class>
</hibernate-mapping>

<hibernate-mapping package="com.sl.many2many">
	<class name="Teacher">
		<id name="id" column="t_id">
			<generator class="native" />
		</id>
		<property name="name" column="t_name"/>
		<set name="students" table="s_t">
			<key column="teacherID"></key>
			<many-to-many column="studentID" class="Student"></many-to-many>
		</set>
	</class>
</hibernate-mapping>