MyBatis中多条件查询商品的三种方法及区别 MyBatis中多条件查询商品的三种

一、Sql语句设置多个参数有几种方式
二、代码附上

一、Sql语句设置多个参数有几种方式 1、散装参数:需要使用@Param标记Sql语句中占位符处的名称例如 #{name}

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2、实体类封装参数
只需要保证Sql中的参数名和实体类属性名对应上，即可设置成功
BrandMapper.xml中的SQL语句不用动，把TestBrandMapper中的代码修改即可

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3、Map集合
【MyBatis中多条件查询商品的三种方法及区别】只需要保证Sql中的参数名和Map集合的键的名称对应上，即可设置成功。
BrandMapper.xml中Sql语句不用改
定义一个默认的map即可

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二、代码附上 0、pom.xml中依赖

org.mybatismybatis3.5.5mysqlmysql-connector-java5.1.46junitjunit4.13testorg.slf4jslf4j-api1.7.20ch.qos.logbacklogback-classic1.2.3ch.qos.logbacklogback-core1.2.3

1、数据库创建

-- 删除tb_brand表drop table if exists tb_brand; -- 创建tb_brand表create table tb_brand(-- id 主键idint primary key auto_increment,-- 品牌名称brand_namevarchar(20),-- 企业名称company_name varchar(20),-- 排序字段orderedint,-- 描述信息descriptionvarchar(100),-- 状态：0：禁用1：启用statusint); -- 添加数据insert into tb_brand (brand_name, company_name, ordered, description, status)values ('三只松鼠', '三只松鼠股份有限公司', 5, '好吃不上火', 0),('华为', '华为技术有限公司', 100, '华为致力于把数字世界带入每个人、每个家庭、每个组织，构建万物互联的智能世界', 1),('小米', '小米科技有限公司', 50, 'are you ok', 1);

2、Brand实体类

package com.ligong.popj; public class Brand {// id 主键private Integer id; // 品牌名称private String brandName; // 企业名称private String companyName; // 排序字段private Integer ordered; // 描述信息private String description; // 状态：0：禁用1：启用private Integer status; public Brand() {}public Brand(Integer id, String brandName, String companyName, Integer ordered, String description, Integer status) {this.id = id; this.brandName = brandName; this.companyName = companyName; this.ordered = ordered; this.description = description; this.status = status; }/*** 获取* @return id*/public Integer getId() {return id; }/*** 设置* @param id*/public void setId(Integer id) {this.id = id; }/*** 获取* @return brandName*/public String getBrandName() {return brandName; }/*** 设置* @param brandName*/public void setBrandName(String brandName) {this.brandName = brandName; }/*** 获取* @return companyName*/public String getCompanyName() {return companyName; }/*** 设置* @param companyName*/public void setCompanyName(String companyName) {this.companyName = companyName; }/*** 获取* @return ordered*/public Integer getOrdered() {return ordered; }/*** 设置* @param ordered*/public void setOrdered(Integer ordered) {this.ordered = ordered; }/*** 获取* @return description*/public String getDescription() {return description; }/*** 设置* @param description*/public void setDescription(String description) {this.description = description; }/*** 获取* @return status*/public Integer getStatus() {return status; }/*** 设置* @param status*/public void setStatus(Integer status) {this.status = status; }public String toString() {return "Brand{id = " + id + ", brandName = " + brandName + ", companyName = " + companyName + ", ordered = " + ordered + ", description = " + description + ", status = " + status + "}"; }//省略 setter and getter。自己写时要补全这部分代码}

3、BrandMap接口

package com.ligong.mapper; import com.ligong.popj.Brand; import org.apache.ibatis.annotations.Param; import java.util.List; import java.util.Map; public interface BrandMapper {List selectByCondition1(@Param("status")int status,@Param("companyName") String companyName,@Param("brandName") String brandName); List selectByCondition2(Brand brand); List selectByCondition3(Map map); }

4、BrandMapper.xml映射代码

select * fromtb_brand where status = #{status} andcompany_name like#{companyName} andbrand_namelike #{brandName}; select * fromtb_brandwhere status = #{status} andcompany_name like#{companyName} andbrand_namelike #{brandName}; select * fromtb_brandwhere status = #{status} andcompany_name like#{companyName} andbrand_namelike #{brandName};

5、封装好的连接数据库的工具类

package com.ligong.util; import org.apache.ibatis.io.Resources; import org.apache.ibatis.session.SqlSession; import org.apache.ibatis.session.SqlSessionFactory; import org.apache.ibatis.session.SqlSessionFactoryBuilder; import java.io.IOException; import java.io.InputStream; public class SqlSessionUtils {private static SqlSession sqlSession=null; private SqlSessionUtils() {}static {try {String resource = "mybatis-config.xml"; InputStream inputStream = Resources.getResourceAsStream(resource); SqlSessionFactory sqlSessionFactory = new SqlSessionFactoryBuilder().build(inputStream); sqlSession = sqlSessionFactory.openSession(); } catch (IOException e) {e.printStackTrace(); }}public static SqlSession getSqlSession(){return sqlSession; }}

6、Test类中的特使代码

package com.ligong.mapper; import com.itheima.popj.Brand; import com.itheima.popj.Dept; import com.itheima.util.SqlSessionUtils; import org.apache.ibatis.session.SqlSession; import org.junit.After; import org.junit.Before; import org.junit.Test; import java.util.HashMap; import java.util.List; import java.util.Map; public class TestBrandMapper {private static BrandMapper mapper = null; private static SqlSession sqlSession = null; @Beforepublic void init() {sqlSession = SqlSessionUtils.getSqlSession(); mapper = sqlSession.getMapper(BrandMapper.class); }@Afterpublic void finallyOp() {sqlSession.close(); }@Testpublic void selectByCondition3() {int status = 1; String brand_name = "华"; String company_name = "华"; String brandName = "%" + brand_name + "%"; String companyName = "%" + company_name + "%"; Map map = new HashMap(); map.put("status", status); map.put("brandName", companyName); map.put("companyName", brandName); List brands = mapper.selectByCondition3(map); for (Brand brand1 : brands) {System.out.println(brand1); }}@Testpublic void selectByCondition2() {int status = 1; String brand_name = "华"; String company_name = "华"; String brandName = "%" + brand_name + "%"; String companyName = "%" + company_name + "%"; Brand brand = new Brand(); brand.setStatus(1); brand.setBrandName(brandName); brand.setCompanyName(companyName); List brands = mapper.selectByCondition2(brand); for (Brand brand1 : brands) {System.out.println(brand1); }}@Testpublic void selectByCondition1() {int status = 1; String brand_name = "华为"; String company_name = "华"; String brandName = "%" + brand_name + "%"; String companyName = "%" + company_name + "%"; List brands = mapper.selectByCondition1(status,companyName,brandName); for (Brand brand : brands) {System.out.println(brand); }}@Testpublic void findAll() {SqlSession sqlSession = SqlSessionUtils.getSqlSession(); DeptMapper mapper = sqlSession.getMapper(DeptMapper.class); List all = mapper.findAll(); for (Dept dept : all) {System.out.println(dept); }}}

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