常用,上菜。
一、
1、一对一关系
例子:Person(人)类和Card(身份证)类
Person实体类:
private int pid;
private String pname;
private Card card; //一对一 get、set....
Card实体类:
private int cid;
private String cnumber;
2、然后,生成person.xml,这里我就把card.xml浓缩在person.xml里面去了:
<resultMap id="myPersonMap" type="com.desert.entity.Person">
<id property="pid" column="pid"></id>
<result property="pname" column="pname"></result>
<association property="card" javaType="com.desert.entity.Card">
<id property="cid" column="cid"></id>
<result property="cnumber" column="cnumber"></result>
</association>
</resultMap>
二、
1、一对多关系
例子:Provinces(省份)类和City(城市)类
Provinces 实体类:
private int pid;
private String pname;
private Set<City> citysSet;
City 实体类:
private int cid;
private String cname;
private int pid;
2、然后,生成Provinces.xml,这里我就把city.xml浓缩在Provinces .xml里面去了:
<resultMap id="myProvincesMap" type="com.desert.entity.Provinces">
<id property="pid" column="pid"></id>
<result property="pname" column="pname"></result>
<collection property="citysSet" ofType="com.desert.entity.City">
<id property="cid" column="cid"></id>
<result property="cname" column="cname"></result>
<result property="pid" column="pid"></result>
</collection>
</resultMap>
三、
1、多对多关系
例子:Users(用户)类和Roles(角色)类
Users 实体类:
private int uid;
private String uname;
private Set<Roles> roles;
Roles 实体类:
private int rid;
private String rname;
private Set<Users> users;
2、然后,生成Users.xml:
<resultMap type="com.desert.entity.Users" id="usersMap">
<id property="uid" column="uid" />
<result property="uname" column="uname" />
</resultMap>
<resultMap type="com.desert.entity.Users" id="usersRolesMap" extends="usersMap">
<collection property="roles" ofType="com.desert.entity.Roles">
<id property="rid" column="rid" />
<result property="rname" column="rname" />
</collection>
</resultMap>
然后,再生成Roles .xml:
<resultMap type="com.desert.entity.Roles" id="rolesMap">
<id property="rid" column="rid" />
<result property="rname" column="rname" />
</resultMap>
<resultMap type="com.desert.entity.Roles" id="rolesUsersMap" extends="rolesMap">
<collection property="users" ofType="com.desert.entity.Users">
<id property="uid" column="uid" />
<result property="uname" column="uname" />
</collection>
</resultMap>