MyBatis傳入引數為list、陣列、map寫法
阿新 • • 發佈:2021-10-15
1.foreach簡單介紹:
foreach的主要用在構建in條件中,它可以在SQL語句中進行迭代一個集合。
foreach元素的屬性主要有item,index,collection,open,separator,close。
item表示集合中每一個元素進行迭代時的別名,
index指定一個名字,用於表示在迭代過程中,每次迭代到的位置,
open表示該語句以什麼開始,
separator表示在每次進行迭代之間以什麼符號作為分隔符,
close表示以什麼結束,
collection屬性是在使用foreach的時候最關鍵的也是最容易出錯的,該屬性是必須指定的,但是在不同情況下,該屬性的值是不一樣的,主要有一下3種情況:
(1)如果傳入的是單引數且引數型別是一個List的時候,collection屬性值為list .
(2)如果傳入的是單引數且引數型別是一個array陣列的時候,collection的屬性值為array .
(3)如果傳入的引數是多個的時候,我們就需要把它們封裝成一個Map了,當然單引數也可以封裝成map,實際上如果你在傳入引數的時候,在MyBatis裡面也是會把它封裝成一個Map的,map的key就是引數名,所以這個時候collection屬性值就是傳入的List或array物件在自己封裝的map裡面的key.
2.實踐-實體類
- public class Employees {
- private Integer employeeId;
- private String firstName;
- private String lastName;
- private String email;
- private String phoneNumber;
- private Date hireDate;
- private String jobId;
- private BigDecimal salary;
- private BigDecimal commissionPct;
-
private Integer managerId;
- private Short departmentId;
- }
3.實踐-XML
- <!--List:forech中的collection屬性型別是List,collection的值必須是:list,item的值可以隨意,Dao介面中引數名字隨意 -->
- <select id="getEmployeesListParams" resultType="Employees">
- select *
- from EMPLOYEES e
- where e.EMPLOYEE_ID in
- <foreach collection="list" item="employeeId" index="index"
- open="(" close=")" separator=",">
- #{employeeId}
- </foreach>
- </select>
- <!--Array:forech中的collection屬性型別是array,collection的值必須是:list,item的值可以隨意,Dao介面中引數名字隨意 -->
- <select id="getEmployeesArrayParams" resultType="Employees">
- select *
- from EMPLOYEES e
- where e.EMPLOYEE_ID in
- <foreach collection="array" item="employeeId" index="index"
- open="(" close=")" separator=",">
- #{employeeId}
- </foreach>
- </select>
- <!--Map:不單單forech中的collection屬性是map.key,其它所有屬性都是map.key,比如下面的departmentId -->
- <select id="getEmployeesMapParams" resultType="Employees">
- select *
- from EMPLOYEES e
- <where>
- <if test="departmentId!=null and departmentId!=''">
- e.DEPARTMENT_ID=#{departmentId}
- </if>
- <if test="employeeIdsArray!=null and employeeIdsArray.length!=0">
- AND e.EMPLOYEE_ID in
- <foreach collection="employeeIdsArray" item="employeeId"
- index="index" open="(" close=")" separator=",">
- #{employeeId}
- </foreach>
- </if>
- </where>
- </select>
4.實踐-Mapper
- public interface EmployeesMapper {
- List<Employees> getEmployeesListParams(List<String> employeeIds);
- List<Employees> getEmployeesArrayParams(String[] employeeIds);
- List<Employees> getEmployeesMapParams(Map<String,Object> params);
-
}
Mybaits 遍歷Map【註解使用】
1、遍歷map
1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 package
com.isuzu.vehicle.onroad.dal.mapper;
import
com.baomidou.mybatisplus.core.mapper.BaseMapper;
import
com.isuzu.vehicle.onroad.dal.entity.VehicleOnroad;
import
com.isuzu.vehicle.onroad.service.vo.VehicleOnroadVo;
import
com.ne.ice.boot.common.entity.Page;
import
org.apache.ibatis.annotations.Param;
import
org.apache.ibatis.annotations.Result;
import
org.apache.ibatis.annotations.Results;
import
org.apache.ibatis.annotations.Select;
import
org.apache.ibatis.type.JdbcType;
import
java.util.Date;
import
java.util.List;
import
java.util.Map;
/**
* @author Yungui.Zheng
*/
public
interface
VehicleOnroadMapper
extends
BaseMapper<VehicleOnroad>
{
/**
* 分頁查詢
* @param page 分頁物件
* @param conditionMap 條件map
* @param order 排序
* @return 分頁list
*/
@Select
(
"<script>"
+
" select "
+
" * "
+
" FROM "
+
" tm_vehicle_onroad "
+
" <where> "
+
" <foreach collection=\"cond.keys\" item=\"wkey\" >"
+
" <choose> "
+
" <when test=\"wkey =='vin'\"> "
+
//關鍵詞
" and vin like concat('%',#{cond[${wkey}]},'%') "
+
" </when> "
+
" <when test=\"wkey =='vinList'\"> "
+
//使用者vinList
" and vin in (\n"
+
" <foreach collection=\"cond[wkey]\" item=\"item\" index=\"index\" separator=\",\">\n"
+
" #{item}\n"
+
" </foreach>) "
+
" </when> "
+
" <when test=\"wkey =='from'\"> "
+
//開始時間
" and create_time >=#{cond[${wkey}]} "
+
" </when> "
+
" <when test=\"wkey =='to'\"> "
+
//結束時間
" and create_time <=#{cond[${wkey}]} "
+
" </when> "
+
" <otherwise> "
+
" <if test=\"cond[wkey]!= null\">and ${wkey}= #{cond[${wkey}]}</if> "
+
" </otherwise> "
+
" </choose>"
+
"</foreach> "
+
" </where> "
+
" <if test=\"order!= null\"> ${order}</if> "
+
"</script>"
)
List<VehicleOnroad> selectPageByMap(Page<VehicleOnroad> page,
@Param
(
"cond"
) Map<String, Object> conditionMap,
@Param
(
"order"
) String order) ;
}