Hibernate中一对一关联
在hibernate中实现一对一的关联有两种方法，分别是共享主键关联和唯一外键关联
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（1）共享主键关联
有两个表 user和profile
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user表中有id（主键） username password
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profile表中有id(主键) email phone
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其实profile表正是从user表中分割出来的，
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设置相应的类User类，和profile类
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user类中的字段
??? private Integer id;
??? private String username;
??? private String password;
??? private Profile profile;
生成对应的get/set方法
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profile表中的字段
??? private Integer id;
??? private String email;
??? private String phone;
??? private User user;
生成对应的get/set方法
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在User.hbm.xml中
??? <class name="com.cheng.entry.User" table="user">
?? ??? ?<id name="id" type="java.lang.Integer">
?? ??? ??? ?<column name="id"></column>
?? ??? ??? ?<generator type="java.lang.String">
?? ??? ??? ?<column name="username" length="200"></column>
?? ??? ?</property>
?? ??? ?<property name="password" type="java.lang.String">
?? ??? ??? ?<column name="password" length="200"></column>
?? ??? ?</property>
?? ??? ?<one-to-one name="profile(这个就是user表中设置的属性)" table="profile">
??? ??? <id name="id" type="java.lang.Integer">
??? ??? ??? <column name="id"></column>
??? ??? ??? <generator type="java.lang.String">
??? ??? ??? <column name="email" length="200"></column>
??? ??? </property>
??? ??? <property name="phone" type="java.lang.String">
??? ??? ??? <column name="phone" length="200"></column>
??? ??? </property>
??? ??? <one-to-one name="user" table="profile">
??? ??? <id name="id" type="java.lang.Integer">
??? ??? ??? <column name="id"></column>
??? ??? ??? <generator type="java.lang.String">
??? ??? ??? <column name="email" length="200"></column>
??? ??? </property>
??? ??? <property name="phone" type="java.lang.String">
??? ??? ??? <column name="phone" length="200"></column>
??? ??? </property>
??? ??? <many-to-one name="user" unique="true">
??? ??? ??? <column name="u_id"></column>
??? ??? </many-to-one>
??? </class>
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红色的字体表示修改过的
