老师和学生，最典型的多对多关联，
Teacher和Student，所谓单向意思就是说，老师知道自己的教的是哪些学生而学生不知道是哪些老师教。也可以这么说，在查询的时候，通过老师可以级联查询出学生，但是通过学生不可以级联查询出老师！
而多对多最麻烦的是怎么自定义我们中间表的，表名和列名，这个是重要的！
Annotations配置
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@Entity
@Table
(name=
"t_teacher"
)
publicclass Teacher {
private
Integer id;
private
String name;
private
Set<Student> students=
new
HashSet<Student>();
//set不允许重复，最适合数据库模型
@Id
@GeneratedValue
public
Integer getId() {
returnid;
}
publicvoid setId(Integerid) {
this
.id = id;
}
@Column
(name=
"t_name"
)
public
String getName() {
returnname;
}
publicvoid setName(Stringname) {
this
.name = name;
}
@ManyToMany
@JoinTable
(name=
"t_s_two"
,
//自定义表名
joinColumns={
@JoinColumn
(name=
"teacher_id"
)},
//自定义列名
inverseJoinColumns={
@JoinColumn
(name=
"student_id"
)})
//反转，和Teacher对应的那个表的列名，也是自定义
public
Set<Student>getStudents() {
returnstudents;
}
publicvoidsetStudents(Set<Student> students) {
this
.students = students;
}
}
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@Entity
@Table
(name=
"t_student"
)
publicclass Student {
private
Integer id;
private
String name;
private
Integer age;
@Id
@GeneratedValue
public
Integer getId() {
returnid;
}
publicvoid setId(Integerid) {
this
.id = id;
}
@Column
(name=
"s_name"
)
public
String getName() {
returnname;
}
publicvoid setName(Stringname) {
this
.name = name;
}
@Column
(name=
"s_age"
)
public
Integer getAge() {
returnage;
}
publicvoid setAge(Integerage) {
this
.age = age;
}
}
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XML配置
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publicclass Teacher {
private
Integer id;
private
String name;
private
Set<Student> students=newHashSet<Student>();
//set不允许重复，最适合数据库模型
public
Integer getId() {
returnid;
}
publicvoid setId(Integerid) {
this
.id = id;
}
public
String getName() {
returnname;
}
publicvoid setName(Stringname) {
this
.name = name;
}
public
Set<Student>getStudents() {
returnstudents;
}
publicvoidsetStudents(Set<Student> students) {
this
.students = students;
}
}
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publicclass Student {
private
Integer id;
private
String name;
private
Integer age;
public
Integer getId() {
returnid;
}
publicvoid setId(Integerid) {
this
.id = id;
}
public
String getName() {
returnname;
}
publicvoid setName(Stringname) {
this
.name = name;
}
public
Integer getAge() {
returnage;
}
publicvoid setAge(Integerage) {
this
.age = age;
}
}
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<?
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
package
=
"csg.hibernate.entity"
>
<
class
name
=
"Teacher"
table
=
"t_teacher"
>
<
id
name
=
"id"
>
<
column
name
=
"id"
/>
<
generator
class
=
"native"
/>
</
id
>
<
property
name
=
"name"
/>
<
set
name
=
"students"
table
=
"t_s_two"
><!—-自定义表名-->
<
key
column
=
"teacher_id"
/><!—自定义列名-->
<
many-to-many
class
=
"csg.hibernate.entity.Student"
column
=
"student_id"
/><!—自定义列名-->
</
set
>
</
class
>
</
hibernate-mapping
>
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<?
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
package
=
"csg.hibernate.entity"
>
<
class
name
=
"Student"
table
=
"t_student"
>
<
id
name
=
"id"
>
<
column
name
=
"id"
/>
<
generator
class
=
"native"
/>
</
id
>
<
property
name
=
"name"
/>
<
property
name
=
"age"
/>
</
class
>
</
hibernate-mapping
>
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以上就是XML的many-to-many(单向)的配置方法
本文转自 小夜的传说 51CTO博客，原文链接：http://blog.51cto.com/1936625305/1568903，如需转载请自行联系原作者
