hibernate三

一、一对多|多对一 关系

package crm.domain;import java.util.HashSet;import java.util.Set;public class Customer {    private Long cust_id;    private String cust_name;    private String cust_linkman;    private String cust_phone;    private String cust_mobile;    private Base_Dict cust_source;    private Base_Dict cust_industry;    private Base_Dict cust_level;    private Set<LinkMan> linkMans = new HashSet<LinkMan>();    public Base_Dict getCust_source() {        return cust_source;    }    public void setCust_source(Base_Dict cust_source) {        this.cust_source = cust_source;    }    public Base_Dict getCust_industry() {        return cust_industry;    }    public void setCust_industry(Base_Dict cust_industry) {        this.cust_industry = cust_industry;    }    public Base_Dict getCust_level() {        return cust_level;    }    public void setCust_level(Base_Dict cust_level) {        this.cust_level = cust_level;    }    public Long getCust_id() {        return cust_id;    }    public void setCust_id(Long cust_id) {        this.cust_id = cust_id;    }    public String getCust_name() {        return cust_name;    }    public void setCust_name(String cust_name) {        this.cust_name = cust_name;    }    public String getCust_linkman() {        return cust_linkman;    }    public void setCust_linkman(String cust_linkman) {        this.cust_linkman = cust_linkman;    }    public String getCust_phone() {        return cust_phone;    }    public void setCust_phone(String cust_phone) {        this.cust_phone = cust_phone;    }    public String getCust_mobile() {        return cust_mobile;    }    public void setCust_mobile(String cust_mobile) {        this.cust_mobile = cust_mobile;    }    @Override    public String toString() {        return "Customer [cust_id=" + cust_id + ", cust_name=" + cust_name + "]";    }    public Set<LinkMan> getLinkMans() {        return linkMans;    }    public void setLinkMans(Set<LinkMan> linkMans) {        this.linkMans = linkMans;    }}        <set name="linkMans" table="linkman" inverse="true" lazy="true">            <key>                <column name="lkm_id" />            </key>            <one-to-many class="crm.domain.LinkMan" />        </set>

public class LinkMan {    private Long lkm_id;    private Character lkm_gender;    private String lkm_name;    private String lkm_phone;    private String lkm_email;    private String lkm_qq;    private String lkm_mobile;    private String lkm_memo;    private String lkm_position;    //表达多对一关系    private Customer customer ;        <many-to-one name="customer" class="crm.domain.Customer" fetch="join" column="cust_id">        </many-to-one>

关于表与表的关系就不介绍了 学数据库吧
关于对象的关系就是
比如有 一个辅导员对应很多个学生
一个学生只能有一个辅导员
辅导员类中加入Set集合来记录学生们
学生类中加入一个辅导员类
关于.hbm.xml中添加设置

        <set name="students" inverse="true" cascade="save-update"> //有set集合的一方(也就是辅导员)            <key>                <column name="stu_id" />            </key>            <one-to-many class="student" />        </set>

set后边的name 是类里边的那个set成员变量
inverse是不是要维护关系 ，反转即true为不维护
cascade为级联属性
分别有：all、save-update、delete 不建议使用
key中 column name 中是学生类中那个外键
one-to-many class是学生类

        <many-to-one name="teacher" class="teacher" column="t_id" >        </many-to-one>

name是学生类中的那个辅导员属性
class是辅导员类
column是学生类的外键

二、多对多 关系

        <set name="users" table="sys_user_role">        <key column="role_id" ></key>        <many-to-many class="User" column="user_id"></many-to-many>        </set>

        <set name="roles" inverse="true" table="sys_user_role">        <key column="user_id"></key>        <many-to-many class="Role" column="role_id"></many-to-many>        </set>

其中一方必须放弃维护关系 也就是 inverse 为true
table是指的第三张表