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hibernate 一对多(级联关系)
hibernate 核心配置文件
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-configuration PUBLIC "-//Hibernate/Hibernate Configuration DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-configuration-3.0.dtd"> <hibernate-configuration> <session-factory> <!-- DataSource配置 --> <property name="connection.driver_class">com.mysql.jdbc.Driver</property> <property name="connection.url">jdbc:mysql://localhost:3306/test</property> <property name="connection.username">root</property> <property name="connection.password"></property> <!-- 指定连接数据库所使用的SQL方言--> <property name="dialect">org.hibernate.dialect.MySQLDialect</property> <!-- 控制台是否输出SQL语句 --> <property name="show_sql">true</property> <!-- 式化Hibernate的SQL输出语句 --> <property name="hibernate.format_sql">true</property> <!-- 指定程序是否在数据库自动创建表 --> <property name="hbm2ddl.auto">update</property> <!-- 指定映射文件的路径 --> <mapping resource="zr/com/pojo/TeamClass.hbm.xml"/> <mapping resource="zr/com/pojo/Student.hbm.xml"/> </session-factory> </hibernate-configuration>
实体类的映射关系
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping package="zr.com.pojo"> <!-- 配置映射关系 --> <class name="TeamClass" table="team_class"> <!-- 配置主键和对应主键的属性 --> <id name="classID" column="class_id"> <generator class="native"/> </id> <!-- 配置属性和相对应数据的列 --> <property name="lfname" column="class_name"/> <!-- 集合 cascade="all" 级联关系 inverse="true" 放弃管理外键 --> <set name="students" table="student" cascade="all" inverse="true"> <!-- 外键 --> <key column="class_id"/> <!-- 一对多 --> <one-to-many class="zr.com.pojo.Student"/> </set> </class> </hibernate-mapping>
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN" "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd"> <hibernate-mapping> <!-- 映射关系 --> <class name="zr.com.pojo.Student" table="student"> <id name="id" column="stu_id"> <!-- 生成主键id的方式 --> <generator class="native"/> </id> <property name="name" column="stu_name"/> <!-- <property name="classId" column="class_id"/> --> <many-to-one name="teamClass" class="zr.com.pojo.TeamClass" column="class_id" cascade="all"/> </class> </hibernate-mapping>
package zr.com.pojo;
public class Student {
private int id;
private String name;
private TeamClass teamClass;
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 TeamClass getTeamClass() {
return teamClass;
}
public void setTeamClass(TeamClass teamClass) {
this.teamClass = teamClass;
}
public Student() {
super();
}
public Student(int id, String name, TeamClass teamClass) {
super();
this.id = id;
this.name = name;
this.teamClass = teamClass;
}
@Override
public String toString() {
return "Student [id=" + id + ", name=" + name + ", teamClass="
+ teamClass + "]";
}
}
package zr.com.pojo; import java.util.HashSet; import java.util.Set; public class TeamClass { private int classID; private String lfname; private Set<Student> students = new HashSet<Student>(); public int getClassID() { return classID; } public void setClassID(int classID) { this.classID = classID; } public String getLfname() { return lfname; } public void setLfname(String lfname) { this.lfname = lfname; } public Set<Student> getStudents() { return students; } public void setStudents(Set<Student> students) { this.students = students; } public TeamClass() { super(); } public TeamClass(int classID, String lfname, Set<Student> students) { super(); this.classID = classID; this.lfname = lfname; this.students = students; } @Override public String toString() { return "TeamClass [classID=" + classID + ", lfname=" + lfname + ", students=" + students + "]"; } }
package zr.com.test; import java.util.List; import java.util.UUID; import org.hibernate.Criteria; import org.hibernate.Session; import org.hibernate.SessionFactory; import org.hibernate.cfg.Configuration; import org.hibernate.service.ServiceRegistry; import org.hibernate.service.ServiceRegistryBuilder; import zr.com.pojo.Student; import zr.com.pojo.TeamClass; public class TestClass { public static void main(String[] args) { // 创建Configuration 对象 Configuration configuration = new Configuration().configure("hibernate.cfg.xml"); // 创建ServiceRegistry 对象 ServiceRegistry serviceRegistry = new ServiceRegistryBuilder().applySettings(configuration.getProperties()).buildServiceRegistry(); // 创建SessionFactory 对象 SessionFactory sessionFactory = configuration.buildSessionFactory(serviceRegistry); // 创建Session 对象 Session session = sessionFactory.openSession(); // 开启事务 session.beginTransaction(); // 创建实体类 Student student1= new Student(); student1.setName("lf"); Student student2= new Student(); student2.setName("gl"); TeamClass teamClass = new TeamClass(); teamClass.setLfname("java"); teamClass.getStudents().add(student1); teamClass.getStudents().add(student2); // 插入数据 session.save(teamClass); // 提交事务 session.getTransaction().commit(); } }
hibernate 一对多(级联关系)
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