Hibernate的一对一关系
时间:2011-01-07
一对一关系的维护有两种，分为主键关联和唯一外键关联
一对一关系的维护有两种，分为主键关联和唯一外键关联
主键关联：（双向）
(主控方)
Person.java
Person {
private String username;
//对被控方的引用
private Address address;
public String getUsername() {
return username;
}
public void setUsername(String username) {
this.username = username;
}
public Address getAddress() {
return address;
}
public void setAddress(Address address) {
this.address= address;
}
}
(被动方)
Address.java
Address{
private String addressName;
//对主控方的引用
private Person person;
public String getAddressName() {
return addressName;
}
public void setAddressName(String addressName) {
this.addressName= addressName;
}
public Person getPerson() {
return person;
}
public void setPerson(Person person) {
this.person= person;
}
public String toString() {
return new ToStringBuilder(this).
append("addressName", addressName).
toString();
}
public boolean equals(Object o) {
if ( !(o instanceof Address) {
return false;
}
Address rhs = (Address) o;
return new EqualsBuilder()
.appendSuper(super.equals(o))
.append(this.addressName, rhs.getAddressName())
.isEquals();
}
public int hashCode() {
return new HashCodeBuilder(17, 37).
append(addressName).
toHashCode();
}
}
mapping 文件
<class name="Person" table="person">
<id name="id" type="long" column="id">
<generator class="native"/>
</id>
<property name="username" column="username" type="string"/>
<one-to-one
name="address"
class="Address"
cascade="all"
constrained="false"
/>
</class>
<class name="Address" table="Address" >
<id name="id" column="id">
<generator class="foreign">
<param name="property">person</param>
</generator>
</id>
<one-to-one name="person" class="Person" constrained="true"/>
<property name="addressName" column="addressName" type="string"/>
</class>
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