2. 程式人生 > >Hibernate級聯操作Cascade學之---delete

Hibernate級聯操作Cascade學之---delete

阿新 • • 發佈：2019-01-03

所在cascade，就是說我在更新一方的時候，可以根據這一方物件之間的關聯關係，去對被關聯方進行持久化，比如說Team和Student之間的1對多關係，使用cascade,可以在team方維護其持有的student集合時，自動對其新增，修改，刪除的student物件進行持久化，而沒必要顯示的進行session.save(student)操作，cascade="delete"的意思就是說，我在session.delete(team)的時候，可以一併刪除其所有的student

資料庫指令碼：

createtable student(id varchar(32) primarykey,
                     team_id 
varchar(32),
                     name varchar(32),
                     cardid varchar(32),
                     age int);

createtable team(id varchar(32) primarykey,
                  team_id varchar(32),
                  teamname varchar(32));

                         
insertinto team values("1","1","team1");
insertinto student values("1","1","stu1","20070101",22);
insertinto student values("2","1","stu2","20070102",23);

持久化JavaBean

package Cascade.saveUpdate;


publicclass Student {
  private String id;
  private String cardid;
  private String name;
  privateint age;
  private Team team;
public String getId() 
{
    return id;
}
publicvoid setId(String id) {
    this.id = id;
}
public String getCardid() {
    return cardid;
}
publicvoid setCardid(String cardid) {
    this.cardid = cardid;
}
public String getName() {
    return name;
}
publicvoid setName(String name) {
    this.name = name;
}
publicint getAge() {
    return age;
}
publicvoid setAge(int age) {
    this.age = age;
}

public Team getTeam() {
    return team;
}
publicvoid setTeam(Team team) {
    this.team = team;
}
}


package Cascade.saveUpdate;


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

publicclass Team {
   private String id;
   private Set students=new HashSet();
   private String teamName;
public String getId() {
    return id;
}
publicvoid setId(String id) {
    this.id = id;
}
public Set getStudents() {
    return students;
}
publicvoid setStudents(Set students) {
    this.students = students;
}
public String getTeamName() {
    return teamName;
}
publicvoid setTeamName(String teamName) {
    this.teamName = teamName;
}


}

Hibernate.cfg.xml

<?xml version='1.0' encoding='UTF-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"
          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">

<!-- Generated by MyEclipse Hibernate Tools.                   -->
<hibernate-configuration>

<session-factory>
    <property name="connection.username">root</property>
    <property name="connection.url">
        jdbc:mysql://localhost:3306/schoolproject?characterEncoding=gb2312&amp;useUnicode=true
    </property>
    <property name="dialect">
        org.hibernate.dialect.MySQLDialect
    </property>
    <property name="myeclipse.connection.profile">mysql</property>
    <property name="connection.password">1234</property>
    <property name="connection.driver_class">
        com.mysql.jdbc.Driver
    </property>
    <property name="hibernate.dialect">
        org.hibernate.dialect.MySQLDialect
    </property>
    <property name="hibernate.show_sql">true</property>
    <property name="current_session_context_class">thread</property>
    <property name="jdbc.batch_size">15</property>
    <mapping resource="Cascade/delete/Student.hbm.xml"/>
    <mapping resource="Cascade/delete/Team.hbm.xml"/>



</session-factory>

</hibernate-configuration>

Student.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 
    Mapping file autogenerated by MyEclipse - Hibernate Tools
-->
<hibernate-mapping>
<class name="Cascade.delete.Student" table="student">
  <id name="id" unsaved-value="null">
    <generator class="uuid.hex"></generator>
  </id>
  <property name="cardid" type="string"/>
  <property name="name" type="string"/>
  <property name="age" type="int"/>
  <many-to-one name="team" 
               column="team_id"
               class="Cascade.delete.Team"
               lazy="no-proxy">
  </many-to-one>
</class>

</hibernate-mapping>

Team.hbm.xml

<?xml version="1.0" encoding="utf-8"?>
<!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<!-- 
    Mapping file autogenerated by MyEclipse - Hibernate Tools
-->
<hibernate-mapping>
<class name="Cascade.delete.Team" table="team" lazy="true">
       <id name="id" column="id">
         <generator class="uuid.hex"></generator>
       </id>
       <property name="teamName" column="teamname"></property>
      
       <set name="students" lazy="true" inverse="false" cascade="delete">
         <key column="team_id"></key>
         <one-to-many class="Cascade.delete.Student"/>
       </set>
      </class>
</hibernate-mapping>

測試程式碼：

package Cascade.delete;


import java.io.File;

import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.Transaction;
import org.hibernate.cfg.Configuration;

publicclass Test