First, many to one
Students and Student classes implement many-to-Grade, corresponding to a plurality of student class.
Student.java entity class, class attributes are mapped.
import java.io.Serializable;
public class Student implements Serializable {
public Student() {
}
public Student(String sname, String sex, String address) {
this.sname = sname;
this.sex = sex;
this.address = address;
}
public Student(String sname, String sex, String address, Grade grade) {
this.sname = sname;
this.sex = sex;
this.address = address;
this.grade = grade;
}
private int sid;
private String sname;
private String sex;
address String Private;
// unidirectional many-: entity objects in one of a plurality of packages of one of
Private Grade Grade;
public int getsid () {
return SID;
}
public void setsid (int SID) {
this.sid = SID ;
}
public String getSname () {
return sname;
}
public void setSname (String sname) {
this.sname sname =;
}
public String getSex () {
return Sex;
}
public void setSex (String Sex) {
this.sex Sex = ;
}
public String getAddress () {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public Grade getGrade() {
return grade;
}
public void setGrade(Grade grade) {
this.grade = grade;
}
@Override
public String toString() {
return "Student [sid=" + sid + ", sname=" + sname + ", sex=" + sex
+ ", address=" + address + "]";
}
}
Student.hbm.xml students mapping file, and add a class of many-relationship
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!-- 实体映射文件：将实体对象映射为数据库中的字段 -->
<class name="com.lxit.entity.Student" table="Student">
<id name="sid" column="sid">
<generator class="native"></generator>
</id>
<property name="sname" column="sname" type="java.lang.String"></property>
<property name="sex" column="sex"></ Property> <-! realize one mapping relationship ->
<Property name = "address" column = "address"> </ Property>
<many-to-one name="grade" class="com.lxit.entity.Grade" column="gid" lazy="false"></many-to-one>
</class>
</hibernate-mapping>
Second, many
Grade.java entity class mapped class and student-to-many, contains a collection of students.
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
public class Grade implements Serializable{
public Grade() {
}
public Grade(String gname) {
this.gname = gname;
}
//在一方添加多方的集合
public Set<Student> students = new HashSet<Student>();
private int gid;
private String gname;
public int getGid() {
return gid;
}
public void setGid(int gid) {
this.gid = gid;
}
public String getGname() {
return gname;
}
public void setGname(String gname) {
this.gname = gname;
}
public Set<Student> getStudents() {
return students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
}
Grade mapping file
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!-- 实体映射文件：将实体对象映射为数据库中的字段 -->
<class name="com.lxit.entity.Grade" table="Grade">
<id name="gid" column="gid">
<generator class="native"></generator>
</id>
<property name="gname" type="java.lang.String">
<column name="gname" length="20"></column>
</ Property> Cascade: Indicates cascading effect, when you save the class, the students saved with the corresponding class inverse: friends said it would maintain the responsibility of parties to maintain the foreign key, default is false
<-!
-->
<set name="students" table="Student" cascade="all">
<key column="gid"></key>
<one-to-many class="com.lxit.entity.Student"/>
</set>
</class>
</hibernate-mapping>
First, many to one
Students and Student classes implement many-to-Grade, corresponding to a plurality of student class.
Student.java entity class, class attributes are mapped.
import java.io.Serializable;
public class Student implements Serializable {
public Student() {
}
public Student(String sname, String sex, String address) {
this.sname = sname;
this.sex = sex;
this.address = address;
}
public Student(String sname, String sex, String address, Grade grade) {
this.sname = sname;
this.sex = sex;
this.address = address;
this.grade = grade;
}
private int sid;
private String sname;
private String sex;
private String address;
@ Unidirectional many-: entity objects in one of a plurality of packages of one of
Private Grade Grade;
public int getsid () {
return SID;
}
public void setsid (int SID) {
this.sid = SID;
}
public String getSname () {
return sname;
}
public void setSname (String sname) {
this.sname sname =;
}
public String getSex () {
return Sex;
}
public void setSex (String Sex) {
this.sex Sex =;
}
public String getAddress () {
return address;
}
public void setAddress(String address) {
this.address = address;
}
public Grade getGrade() {
return grade;
}
public void setGrade(Grade grade) {
this.grade = grade;
}
@Override
public String toString() {
return "Student [sid=" + sid + ", sname=" + sname + ", sex=" + sex
+ ", address=" + address + "]";
}
}
Student.hbm.xml students mapping file, and add a class of many-relationship
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!-- 实体映射文件：将实体对象映射为数据库中的字段 -->
<class name="com.lxit.entity.Student" table="Student">
<id name="sid" column="sid">
<generator class="native"></generator>
</id>
<property name="sname" column="sname" type="java.lang.String"></property>
<property name="sex" column="sex"></property> <-! realize one mapping relationship ->
<Property name = "address" column = "address"> </ Property>
<many-to-one name="grade" class="com.lxit.entity.Grade" column="gid" lazy="false"></many-to-one>
</class>
</hibernate-mapping>
Second, many
Grade.java entity class mapped class and student-to-many, contains a collection of students.
import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;
public class Grade implements Serializable{
public Grade() {
}
public Grade(String gname) {
this.gname = gname;
}
//在一方添加多方的集合
public Set<Student> students = new HashSet<Student>();
private int gid;
private String gname;
public int getGid() {
return gid;
}
public void setGid(int gid) {
this.gid = gid;
}
public String getGname() {
return gname;
}
public void setGname(String gname) {
this.gname = gname;
}
public Set<Student> getStudents() {
return students;
}
public void setStudents(Set<Student> students) {
this.students = students;
}
}
Grade mapping file
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<!-- 实体映射文件：将实体对象映射为数据库中的字段 -->
<class name="com.lxit.entity.Grade" table="Grade">
<id name="gid" column="gid">
<generator class="native"></generator>
</id>
<property name="gname" type="java.lang.String">
<column name="gname" length="20"></column>
</property> -> Cascade: Indicates cascading effect, when you save the class, the class corresponding with the students to save Inverse: friends said it would maintain the responsibility of parties to maintain the foreign key, default is false
<-!
<set name="students" table="Student" cascade="all">
<key column="gid"></key>
<one-to-many class="com.lxit.entity.Student"/>
</set>
</class>
</hibernate-mapping>