步骤5：在mybatis中使用query查询对象

   

第一步:创建BrandQuery对象

 

package com.mybatis.core.query;
 
import java.util.ArrayList;
import java.util.List;
 
public class BrandQuery {
       /**
        * ================================like 查询 字段
        */
       private String name;
       private boolean nameLike;
       public String getName() {
              return name;
       }
       public void setName(String name) {
              this.name = name;
       }
       public boolean isNameLike() {
              return nameLike;
       }
       public void setNameLike(boolean nameLike) {
              this.nameLike = nameLike;
       }
 
       /**
        * =======================order by ==================================================
        */
 
       public class OrderField
       {
              private String fieldName;
              public OrderField(String fieldName, String order) {
                     super();
                     this.fieldName = fieldName;
                     this.order = order;
              }
              private String order;
              public String getFieldName() {
                     return fieldName;
              }
              public void setFieldName(String fieldName) {
                     this.fieldName = fieldName;
              }
              public String getOrder() {
                     return order;
              }
              public void setOrder(String order) {
                     this.order = order;
              }
       }
 
       //创建orderField 集合
       private List<OrderField> orderFields=new ArrayList<BrandQuery.OrderField>();
 
       //提供orderby + * 方法,传递要order by 的属性  例如: orderbyName(boolean isAsc)
 
       public void orderByName(boolean isAsc)
       {
              orderFields.add(new OrderField("name",isAsc? "asc" : "desc"));
       }
 
       public void orderById(boolean isAsc)
       {
              orderFields.add(new OrderField("id",isAsc? "asc" : "desc"));
       }
}

 

第二步:修改BrandDao.xml,增加fields过滤，like和order

 

       <!-- 品牌选择器 -->
       <sql id="brandSelectorByFields">
              SELECT
              <if test="fields != null">
                     ${fields}
              </if>
              <if test="fields == null">
                     id,name,description,img_url,web_site,sort,is_display
              </if>
              FROM bbs_brand
       </sql>
 
       <!-- 品牌条件 -->
       <sql id="brandWhere">
              <where>
                     <if test="name != null">
                           <if test="nameLike == false">
                             name = #{name}
                           </if>
                           <if test="nameLike == true">
                                  and name like "%"#{name}"%"
                           </if>
                     </if>
              </where>
       </sql>
 
       <!-- order by -->
       <sql id="brandListOrder">
              <if test="orderFields != null and orderFields.size > 0">
                     order by
                     <foreach collection="orderFields" separator="," item="orderField">
                           ${orderField.fieldName} ${orderField.order}
                     </foreach>
              </if>
       </sql>
 
       <select id="getBrandList2" parameterType="BrandQuery" resultMap="brand">
              <include refid="brandSelectorByFields" />
              <include refid="brandWhere" />
              <include refid="brandListOrder" />
       </select>

 

第三步:加入getBrandList2接口，加入测试代码

 

@Test
       public void TestGetBrandList2()
       {
              BrandQuery bQuery=new BrandQuery();
              //设置过滤字段
              bQuery.setFields("id,name");
              //设置like 条件
              bQuery.setNameLike(true);
              bQuery.setName("莲");
              //设置order
              bQuery.orderById(true);
 
              List<Brand> brands=  brandService.getBrandList2(bQuery);
              for (Brand brand1 : brands) {
                     System.out.println(brand1.toString());
              }
       }