MyBatis中多条件查询商品的三种方法及区别
作者：Code攻城狮
本文主要介绍了MyBatis中多条件查询商品的三种方法及区别，文中通过示例代码介绍的非常详细，具有一定的参考价值，感兴趣的小伙伴们可以参考一下
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}
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
3、Map集合
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
二、代码附上
0、pom.xml中依赖
<dependencies>
<!--mybatis 依赖-->
<dependency>
<groupId>org.mybatis</groupId>
<artifactId>mybatis</artifactId>
<version>3.5.5</version>
</dependency>
<!--mysql 驱动-->
<dependency>
<groupId>mysql</groupId>
<artifactId>mysql-connector-java</artifactId>
<version>5.1.46</version>
</dependency>
<!--junit 单元测试-->
<dependency>
<groupId>junit</groupId>
<artifactId>junit</artifactId>
<version>4.13</version>
<scope>test</scope>
</dependency>
<!-- 添加slf4j日志api -->
<dependency>
<groupId>org.slf4j</groupId>
<artifactId>slf4j-api</artifactId>
<version>1.7.20</version>
</dependency>
<!-- 添加logback-classic依赖 -->
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-classic</artifactId>
<version>1.2.3</version>
</dependency>
<!-- 添加logback-core依赖 -->
<dependency>
<groupId>ch.qos.logback</groupId>
<artifactId>logback-core</artifactId>
<version>1.2.3</version>
</dependency>
</dependencies>
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
id int primary key auto_increment,
-- 品牌名称
brand_name varchar(20),
-- 企业名称
company_name varchar(20),
-- 排序字段
ordered int,
-- 描述信息
description varchar(100),
-- 状态：0：禁用 1：启用
status int
);
-- 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<Brand> selectByCondition1(
@Param("status")int status,
@Param("companyName") String companyName,
@Param("brandName") String brandName);
List<Brand> selectByCondition2(Brand brand);
List<Brand> selectByCondition3(Map map);
}
4、BrandMapper.xml映射代码
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE mapper
PUBLIC "-//mybatis.org//DTD Mapper 3.0//EN"
"http://mybatis.org/dtd/mybatis-3-mapper.dtd">
<mapper namespace="com.ligong.mapper.BrandMapper">
<select id="selectByCondition1" resultType="com.itheima.popj.Brand">
select * from
tb_brand
where status = #{status} and
company_name like #{companyName} and
brand_name like #{brandName};
</select>
<select id="selectByCondition2" resultType="com.itheima.popj.Brand">
select * from
tb_brand
where status = #{status} and
company_name like #{companyName} and
brand_name like #{brandName};
</select>
<select id="selectByCondition3" resultType="com.itheima.popj.Brand">
select * from
tb_brand
where status = #{status} and
company_name like #{companyName} and
brand_name like #{brandName};
</select>
</mapper>
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;
@Before
public void init() {
sqlSession = SqlSessionUtils.getSqlSession();
mapper = sqlSession.getMapper(BrandMapper.class);
}
@After
public void finallyOp() {
sqlSession.close();
}
@Test
public 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<Brand> brands = mapper.selectByCondition3(map);
for (Brand brand1 : brands) {
System.out.println(brand1);
}
}
@Test
public 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<Brand> brands = mapper.selectByCondition2(brand);
for (Brand brand1 : brands) {
System.out.println(brand1);
}
}
@Test
public void selectByCondition1() {
int status = 1;
String brand_name = "华为";
String company_name = "华";
String brandName = "%" + brand_name + "%";
String companyName = "%" + company_name + "%";
List<Brand> brands = mapper.selectByCondition1(
status,
companyName,
brandName);
for (Brand brand : brands) {
System.out.println(brand);
}
}
@Test
public void findAll() {
SqlSession sqlSession = SqlSessionUtils.getSqlSession();
DeptMapper mapper = sqlSession.getMapper(DeptMapper.class);
List<Dept> all = mapper.findAll();
for (Dept dept : all) {
System.out.println(dept);
}
}
}
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