MyBatis传入参数为list、数组、map写法

1.foreach简单介绍：

foreach的主要用在构建in条件中，它可以在SQL语句中进行迭代一个集合。

foreach元素的属性主要有item，index，collection，open，separator，close。

item表示集合中每一个元素进行迭代时的别名，

index指定一个名字，用于表示在迭代过程中，每次迭代到的位置，

open表示该语句以什么开始，

separator表示在每次进行迭代之间以什么符号作为分隔符，

close表示以什么结束，

collection属性是在使用foreach的时候最关键的也是最容易出错的，该属性是必须指定的，但是在不同情况下，该属性的值是不一样的，主要有一下3种情况： 

（1）如果传入的是单参数且参数类型是一个List的时候，collection属性值为list .

（2）如果传入的是单参数且参数类型是一个array数组的时候，collection的属性值为array .

（3）如果传入的参数是多个的时候，我们就需要把它们封装成一个Map了，当然单参数也可以封装成map，实际上如果你在传入参数的时候，在MyBatis里面也是会把它封装成一个Map的，map的key就是参数名，所以这个时候collection属性值就是传入的List或array对象在自己封装的map里面的key.

2.实践-实体类

 

  1.  
    public class Employees {
  2.  
    private Integer employeeId;
  3.  
    private String firstName;
  4.  
    private String lastName;
  5.  
    private String email;
  6.  
    private String phoneNumber;
  7.  
    private Date hireDate;
  8.  
    private String jobId;
  9.  
    private BigDecimal salary;
  10.  
    private BigDecimal commissionPct;
  11.  
    private Integer managerId;
  12.  
    private Short departmentId;
  13.  
    }

 

3.实践-XML

 

 

  1.  
    <!--List:forech中的collection属性类型是List,collection的值必须是:list,item的值可以随意,Dao接口中参数名字随意 -->
  2.  
    <select id="getEmployeesListParams" resultType="Employees">
  3.  
    select *
  4.  
    from EMPLOYEES e
  5.  
    where e.EMPLOYEE_ID in
  6.  
    <foreach collection="list" item="employeeId" index="index"
  7.  
    open="(" close=")" separator=",">
  8.  
    #{employeeId}
  9.  
    </foreach>
  10.  
    </select>
  11.  
     
  12.  
    <!--Array:forech中的collection属性类型是array,collection的值必须是:list,item的值可以随意,Dao接口中参数名字随意 -->
  13.  
    <select id="getEmployeesArrayParams" resultType="Employees">
  14.  
    select *
  15.  
    from EMPLOYEES e
  16.  
    where e.EMPLOYEE_ID in
  17.  
    <foreach collection="array" item="employeeId" index="index"
  18.  
    open="(" close=")" separator=",">
  19.  
    #{employeeId}
  20.  
    </foreach>
  21.  
    </select>
  22.  
     
  23.  
    <!--Map:不单单forech中的collection属性是map.key,其它所有属性都是map.key,比如下面的departmentId -->
  24.  
    <select id="getEmployeesMapParams" resultType="Employees">
  25.  
    select *
  26.  
    from EMPLOYEES e
  27.  
    <where>
  28.  
    <if test="departmentId!=null and departmentId!=''">
  29.  
    e.DEPARTMENT_ID=#{departmentId}
  30.  
    </if>
  31.  
    <if test="employeeIdsArray!=null and employeeIdsArray.length!=0">
  32.  
    AND e.EMPLOYEE_ID in
  33.  
    <foreach collection="employeeIdsArray" item="employeeId"
  34.  
    index="index" open="(" close=")" separator=",">
  35.  
    #{employeeId}
  36.  
    </foreach>
  37.  
    </if>
  38.  
    </where>
  39.  
    </select>

 

4.实践-Mapper

 

 

  1.  
    public interface EmployeesMapper {
  2.  
     
  3.  
    List<Employees> getEmployeesListParams(List<String> employeeIds);
  4.  
     
  5.  
    List<Employees> getEmployeesArrayParams(String[] employeeIds);
  6.  
     
  7.  
    List<Employees> getEmployeesMapParams(Map<String,Object> params);
  8.  
    }
     
     

    Mybaits 遍历Map【注解使用】

    1、遍历map

    　　

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    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>
    {
     
        /**
         *  分页查询
         * @param page 分页对象
         * @param conditionMap  条件map
         * @param order 排序
         * @return 分页list
         */
        @Select("<script>"
                + " select   "
                +"  *  "
                + " FROM   "
                + "   tm_vehicle_onroad "
                +" <where> "
                +" <foreach collection=\"cond.keys\" item=\"wkey\" >"
                +"  <choose>  " +
                "        <when test=\"wkey =='vin'\">  " +//关键词
                "           and vin like concat('%',#{cond[${wkey}]},'%')  " +
                "        </when>  " +
                "        <when test=\"wkey =='vinList'\">  " +//用户vinList
                "           and vin in (\n" +
                "                <foreach collection=\"cond[wkey]\" item=\"item\" index=\"index\" separator=\",\">\n" +
                "                    #{item}\n" +
                "                </foreach>) " +
                "        </when>  " +
                "        <when test=\"wkey =='from'\">  " +//开始时间
                "           and create_time  >=#{cond[${wkey}]} " +
                "        </when>  " +
                "        <when test=\"wkey =='to'\">  " +//结束时间
                "           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) ;
     
    }
     

1、遍历map

　　

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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>
{
 
    /**
     *  分页查询
     * @param page 分页对象
     * @param conditionMap  条件map
     * @param order 排序
     * @return 分页list
     */
    @Select("<script>"
            + " select   "
            +"  *  "
            + " FROM   "
            + "   tm_vehicle_onroad "
            +" <where> "
            +" <foreach collection=\"cond.keys\" item=\"wkey\" >"
            +"  <choose>  " +
            "        <when test=\"wkey =='vin'\">  " +//关键词
            "           and vin like concat('%',#{cond[${wkey}]},'%')  " +
            "        </when>  " +
            "        <when test=\"wkey =='vinList'\">  " +//用户vinList
            "           and vin in (\n" +
            "                <foreach collection=\"cond[wkey]\" item=\"item\" index=\"index\" separator=\",\">\n" +
            "                    #{item}\n" +
            "                </foreach>) " +
            "        </when>  " +
            "        <when test=\"wkey =='from'\">  " +//开始时间
            "           and create_time  >=#{cond[${wkey}]} " +
            "        </when>  " +
            "        <when test=\"wkey =='to'\">  " +//结束时间
            "           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) ;
 
}

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