Hibernate Many-to-Many

ゝ一纸荒年。 2022-06-08 06:09 166阅读 0赞

声明：本博文用于学习总结及工作心得

在使用hibernate时，经常会遇到对象与对象之间的关系映射，比如一对多，多对一，多对多；这里来聊一下多对多的配置文件

SIPGroup类

public class SIPGroup {
        private Integer id;
        private String name;
        private String orderNumber;//分组号
        private String rules;
        private String attachments;//铃声
        private Set<Gateway> gateways;
        private Set<SIPInfo> sipInfos;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getName() {
            return name;
        }
    
        public void setName(String name) {
            this.name = name;
        }
    
        public String getRules() {
            return rules;
        }
    
        public void setRules(String rules) {
            this.rules = rules;
        }
    
        public String getAttachments() {
            return attachments;
        }
    
        public void setAttachments(String attachments) {
            this.attachments = attachments;
        }
    
        public Set<Gateway> getGateways() {
            return gateways;
        }
    
        public void setGateways(Set<Gateway> gateways) {
            this.gateways = gateways;
        }
    
        public Set<SIPInfo> getSipInfos() {
            return sipInfos;
        }
    
        public void setSipInfos(Set<SIPInfo> sipInfos) {
            this.sipInfos = sipInfos;
        }
    
        public String getOrderNumber() {
            return orderNumber;
        }
    
        public void setOrderNumber(String orderNumber) {
            this.orderNumber = orderNumber;
        }
    }

SIPGroup.hbm,xml

<hibernate-mapping>
        <class name="com.rhxy.bean_new.sip.SIPGroup" table="sipGroup">
            <comment>SIP用户</comment>
            <id name="id" type="java.lang.Integer">
                <column name="id" />
                <generator class="identity" />
            </id>
            <property name="name" type="java.lang.String" column="name"/>
            <property name="orderNumber" type="java.lang.String" column="orderNumber"/>
            <property name="rules" type="java.lang.String" column="rules"/>
            <property name="attachments" type="java.lang.String" column="attachments"/>
            <set name="gateways" lazy="false" inverse="true">
                <key column="sipGroup_id"></key>
                <one-to-many class="com.rhxy.bean_new.sip.Gateway"/>
            </set>
          <set name="sipInfos" table="sipGroup_sipInfo" cascade="all" inverse="false" lazy="false">
                <key column="sipGroup_id"/>
                <many-to-many class="com.rhxy.bean_new.sip.SIPInfo" column="sipInfo_id"/>
            </set>
        </class>
    </hibernate-mapping>

SIPInfo类

public class SIPInfo {
        private Integer id;
        private String username;
        private String passwd;
        private User user;
        private Set<SIPGroup> sipGroups;
    
        public Integer getId() {
            return id;
        }
    
        public void setId(Integer id) {
            this.id = id;
        }
    
        public String getUsername() {
            return username;
        }
    
        public void setUsername(String username) {
            this.username = username;
        }
    
        public String getPasswd() {
            return passwd;
        }
    
        public void setPasswd(String passwd) {
            this.passwd = passwd;
        }
    
        public User getUser() {
            return user;
        }
    
        public void setUser(User user) {
            this.user = user;
        }
    
        public Set<SIPGroup> getSipGroups() {
            return sipGroups;
        }
    
        public void setSipGroups(Set<SIPGroup> sipGroups) {
            this.sipGroups = sipGroups;
        }
    }

SIPInfo.hbm.xml

<hibernate-mapping>
        <class name="com.rhxy.bean_new.sip.SIPInfo" table="sipInfo">
            <comment>SIP用户</comment>
            <id name="id" type="java.lang.Integer">
                <column name="id" />
                <generator class="identity" />
            </id>
            <property name="username" type="java.lang.String" column="username"/>
            <property name="passwd" type="java.lang.String" column="passwd"/>
           <many-to-one name="user" class="com.rhxy.bean_new.personnel.User" column="user_id" lazy="false"/>
            <set name="sipGroups" table="sipGroup_sipInfo" inverse="true" lazy="false">
                <key column="sipInfo_id"/>
                <many-to-many class="com.rhxy.bean_new.sip.SIPGroup" column="sipGroup_id" />
            </set>
        </class>
    </hibernate-mapping>

针对上面的配置做一下说明：都是通过Set的方式来配置，通过table这个属性来指定相应的中间表名称，inverse用于关联控制，cascade用户控制级联操作。  
注意：

1、cascade设置，如果cascade没有设置，那么当我们在保存时将不能级联保存

2、inverse设置：其设置在此尤为关键，inverse表示控制关联关系是否更新到数据库，即：关联关系控制，如果两边都设置为true，即：都不管理、都不主控，此时 Hibernate将不会对关联关系进行维护，即：并没有添加数据到中间表。所以必须一方设置未True，代表主控，一方设置未false