mybatis 註解方式一對一，多重對象關聯，及使用@Result來實現

三個關聯的對象查詢

實體類

public class SchoolEntity ｛
	private SchoolDbEntity db;
    public SchoolDbEntity getDb() {return db;    }
    public void setDb(SchoolDbEntity db) { this.db = db;    }
｝
public class SchoolDbEntity｛
	private DbServerEntity dbSvr;
    public DbServerEntity getDbSvr() { return dbSvr;    }
    public void setDbSvr(DbServerEntity dbSvr) { this.dbSvr = dbSvr;  }
｝
public class DbServerEntity {
｝

映射類：

public interface SchoolMapper {
@SelectProvider(type= SchoolProvider.class,method = "listSql")
    @Results({
            @Result(property = "db",column = "schoolid",
                    one=@One(select = "com.jiapeng.mainsvr.mapper.SchoolDbMapper.getDbByScId"))
    })
    List<SchoolEntity> list(String name, String typeId, int stop, int rows, int page);
    ｝

public interface SchoolDbMapper {
    @Select("select * from sc_db where scId=#{scId}")
    @Results({
            @Result(property = "dbSvr",column="dbSvrId",
                    one=@One(select = "com.jiapeng.mainsvr.mapper.DbServerMapper.getById"))
    })
    SchoolDbEntity getDbByScId(String scId);
}
public interface DbServerMapper {
	@Select("select * from db_server where id=#{id}")
    DbServerEntity getById(String id);
｝

通過@Result來實現，及使用join 關聯兩個表查詢，使用@Result來給實體類的對象中的屬性賦值

實體類： （節省代碼，沒複製get,set）

public class RoomTypeEntity {
    private String id;
    private String name;

    private CodeEntity code;
｝

public class CodeEntity {
    private String code;
    private String name;
    private int type;
}

mapper：（查詢方法,sql中的codeid,codename 只是示例）

   @Select("select *,codeid='t1',codename='n1' from sc_classRoomType order by id")
    @Results({
            @Result(property = "code.code",column = "codeid"),
            @Result(property = "code.name",column = "codename")
    })
    List<RoomTypeEntity> list();

查詢結果：

{"code":200,"msg":null,"content":[{"id":"100","name":"普通","code":{"code":"t1","name":"n1","type":0}},{"id":"101","name":"多媒體","code":{"code":"t1","name":"n1","type":0}},{"id":"102","name":"機房","code":{"code":"t1","name":"n1","type":0}},{"id":"103","name":"實驗室","code":{"code":"t1","name":"n1","type":0}}]}