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  • Hibernate 再接触 一对多单向关联

    在1的方向加多的集合

    Group.java

    package com.bjsxt.hibernate;
    
    import java.util.HashSet;
    import java.util.Set;
    
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.JoinColumn;
    import javax.persistence.OneToMany;
    import javax.persistence.Table;
    
    @Entity
    @Table(name="t_group")
    public class Group {
        private int id;
        private String name;
        private Set<User> users = new HashSet<User>();
        @Id
        @GeneratedValue
        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;
        }
        @OneToMany
        @JoinColumn(name="groupId")    //不写这句话会产生中间表
        public Set<User> getUsers() {
            return users;
        }
        public void setUsers(Set<User> users) {
            this.users = users;
        }
    }
    package com.bjsxt.hibernate;
    
    import javax.persistence.Entity;
    import javax.persistence.GeneratedValue;
    import javax.persistence.Id;
    import javax.persistence.ManyToOne;
    import javax.persistence.Table;
    
    @Entity
    @Table(name="t_user")
    public class User {
        private int id;
        private String name;
        
        
        @Id
        @GeneratedValue
        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;
        }
    }

    User.hbm.xml

    <?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>
        <class name="com.bjsxt.hibernate.User" table="t_user">
            <id name="id">
                <generator class="native"></generator>
            </id>
            
            <property name="name"></property>
            
        </class>
        
    </hibernate-mapping>

    Group.hbm.xml

    <?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>
        <class name="com.bjsxt.hibernate.Group" table="t_group">
            <id name="id">
                <generator class="native"></generator>
            </id>
            
            <property name="name"></property>
            <set name="users">
                <key column="groupId"></key>
                <one-to-many class="com.bjsxt.hibernate.User"/>
            </set>
        </class>
        
    </hibernate-mapping>
    @Test
        public void testSchemaExport() {
            new SchemaExport(new AnnotationConfiguration().configure()).create(false, true);
        }
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  • 原文地址:https://www.cnblogs.com/frankzone/p/9599281.html
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