springboot整合mybatis plus 常见增删改查方法的应用
项目完整图，源码下载地址
https://download.csdn.net/download/qq_41712271/16690360
1 pom.xml配置
mysql
mysql-connector-java
runtime
com.baomidou
mybatis-plus-boot-starter
3.4.1
org.projectlombok
lombok
true
provided
2 application.properties配置
server.port=8081
#==============================数据库相关配置========================================
spring.datasource.driver-class-name =com.mysql.cj.jdbc.Driver
spring.datasource.url=jdbc:mysql://127.0.0.1:3306/cloud_guanggao?useUnicode=true&characterEncoding=utf-8&useSSL=false
spring.datasource.username =root
spring.datasource.password =123456
#==============================mybatis plus 相关配置================================
#默认配置路径
mybatis-plus.mapper-locations=classpath*:/mapper/*Mapper.xml
#配置mybatis plus打印sql日志
mybatis-plus.configuration.log-impl=org.apache.ibatis.logging.stdout.StdOutImpl
#mybatis plus下划线转驼峰配置，默认就是true
mybatis-plus.configuration.map-underscore-to-camel-case=true
#配置文件配置 自定义sql的包扫描
mybatis-plus.type-aliases-package=cn.huawei.guanggao.pojo
#配置全局默认主键类型,实体类就不用加 @TableId(value = "id", type = IdType.AUTO)
mybatis-plus.global-config.db-config.id-type=auto
3 pojo类GuangGao.java编写 和 对应的表
package cn.huawei.guanggao.pojo;
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableField;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableName;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import java.util.Date;
//lombok 相关的注解，生成get,set,全参构造,无参构造
@Data
@AllArgsConstructor
@NoArgsConstructor
//mybatis plus表名映射
@TableName("guanggao")
public class GuangGao {
//mybatis plus 定义表的主键
@TableId(value = "id",type = IdType.AUTO)
private Integer id;
private String title;
//mybatis plus 定义表的非主键字段,因为和数据据的名称不一样，所以才设置，一般不用配置
@TableField(value = "cover_img")
private String coverImg;
private Integer price;
@TableField(value = "create_time")
private Date createTime;
private Double point;
}
4 mybatis plus配置类 MybatisPlusPageConfig.java（分页用）
package cn.huawei.guanggao.config;
import com.baomidou.mybatisplus.annotation.DbType;
import com.baomidou.mybatisplus.extension.plugins.MybatisPlusInterceptor;
import com.baomidou.mybatisplus.extension.plugins.inner.PaginationInnerInterceptor;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
@Configuration
public class MybatisPlusPageConfig {
/* 旧版本配置
@Bean
public PaginationInterceptor paginationInterceptor(){
return new PaginationInterceptor();
}*/
/**
* 新的分页插件 ,拦截器的原理感觉
*/
@Bean
public MybatisPlusInterceptor mybatisPlusInterceptor() {
MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
return interceptor;
}
}5 mapper层，GuangGaoMapper.java
package cn.huawei.guanggao.mapper;
import cn.huawei.guanggao.pojo.GuangGao;
import com.baomidou.mybatisplus.core.mapper.BaseMapper;
import java.util.List;
/**
* Mapper 继承该接口后，无需编写 mapper.xml 文件，即可获得CRUD功能
*/
public interface GuangGaoMapper extends BaseMapper {
//也可以 自定义sql脚本
List getAllGuangGaoList();
}
6 GuangGaoMapper.xml文件 (可省略，只是演示如何使用自定义的sql)
7 启动类 GuanggaoApplication.java 编写
package cn.huawei.guanggao;
import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
@SpringBootApplication
@MapperScan("cn.huawei.guanggao.mapper")
public class GuanggaoApplication {
public static void main(String[] args) {
SpringApplication.run(GuanggaoApplication.class, args);
}
}
8 增删改查方法测试用例 GuanggaoApplicationTests.java
package cn.huawei.guanggao;
import cn.huawei.guanggao.mapper.GuangGaoMapper;
import cn.huawei.guanggao.pojo.GuangGao;
import com.baomidou.mybatisplus.core.conditions.query.QueryWrapper;
import com.baomidou.mybatisplus.core.conditions.update.UpdateWrapper;
import com.baomidou.mybatisplus.core.metadata.IPage;
import com.baomidou.mybatisplus.extension.plugins.pagination.Page;
import org.junit.jupiter.api.Test;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.test.context.SpringBootTest;
import java.util.*;
import java.util.function.Consumer;
@SpringBootTest
class GuanggaoApplicationTests {
@Autowired
private GuangGaoMapper guangGaoMapper;
/*
添加记录,并返回新增记录的id
*/
@Test
void test_2() {
GuangGao a = new GuangGao(null, "a", "a.jpg", 150, new Date(), 155.5);
guangGaoMapper.insert(a);
System.out.println(a.getId());
}
/*
根据id删除，删除 id=66
*/
@Test
void test_3() {
guangGaoMapper.deleteById(66);
}
/*
删除（根据ID 批量删除）
DELETE FROM guanggao WHERE id IN (69,70)
*/
@Test
void test_15() {
guangGaoMapper.deleteBatchIds(Arrays.asList(69, 70));
}
/*
根据 wrapper 条件，删除记录
queryWrapper 实体对象封装操作类（可以为 null,里面的 entity 用于生成 where 语句
DELETE FROM guanggao WHERE (
id = 68
OR
id IN (67,68))
*/
@Test
void test_14() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.eq("id", 68);
wrapper.or();
wrapper.in("id", 67, 68);
guangGaoMapper.delete(wrapper);
}
/*
通用删除操作 deleteByMap map要写列名条件 不能是实体属性名
删除 where id=67 and title=a
*/
@Test
void test_4() {
HashMap map = new HashMap<>();
map.put("id", 67);
map.put("title", "a");
guangGaoMapper.deleteByMap(map);
}
/*
修改操作，根据id
UPDATE guanggao SET title=?, cover_img=? WHERE id=71
*/
@Test
void test_16() {
GuangGao guangGao = new GuangGao();
guangGao.setTitle("光华大道");
guangGao.setCoverImg("http://2.jpg");
guangGao.setId(71);
guangGaoMapper.updateById(guangGao);
}
/*
queryWrapper更新操作
修改 UPDATE guanggao SET title=?, cover_img=? WHERE (id = 65)
*/
@Test
void test_5() {
GuangGao guangGao = new GuangGao();
guangGao.setTitle("森岛帆高");
guangGao.setCoverImg("http://www.baidu.com/img/mv1.jpg");
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.eq("id", 65);
guangGaoMapper.update(guangGao, wrapper);
}
/*
updateWrapper更新操作
UPDATE guanggao SET title=?,cover_img=? WHERE (id = ?)
*/
@Test
void test_6() {
UpdateWrapper wrapper = new UpdateWrapper<>();
wrapper.set("title", "大规模");
wrapper.set("cover_img", "meilv_1.jpg");
wrapper.eq("id", 64);
guangGaoMapper.update(null, wrapper);
}
/*
根据id查询 1个或多个
FROM guanggao WHERE id=65
FROM guanggao WHERE id IN ( 45, 46 )
*/
@Test
void test_17() {
GuangGao guangGao = guangGaoMapper.selectById(65);
List guangGaos = guangGaoMapper.selectBatchIds(Arrays.asList(45, 46));
}
/*
查询操作 QueryWrapper
*/
@Test
void test_1() {
QueryWrapper guangGaoQueryWrapper = new QueryWrapper<>();
List guangGaos =
guangGaoMapper.selectList(guangGaoQueryWrapper);
}
/*
QueryWrapper查询 基本操作,注意select的使用
SELECT id,title FROM guanggao WHERE (id > 20)
*/
@Test
void test_12() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.select("id", "title");
wrapper.gt("id", 20);
guangGaoMapper.selectList(wrapper);
}
/*
查询操作 QueryWrapper ,并排序
WHERE (id IN (60,61,62) AND price > 150)
ORDER BY id DESC,title DESC
*/
@Test
void test_10() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.in("id", Arrays.asList(60, 61, 62));
wrapper.gt("price", 150);
wrapper.orderByDesc("id", "title");
List guangGaos = guangGaoMapper.selectList(wrapper);
}
/*
查询操作 QueryWrapper ，演示 apply,lick
WHERE DATE_FORMAT(create_time,'%Y-%m-%d')>='2021-01-10' AND DATE_FORMAT(create_time,'%Y-%m-%d')<='2021-01-18' AND title LIKE '玩转%'
*/
@Test
void test_7() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.apply("DATE_FORMAT(create_time,'%Y-%m-%d')>={0} and DATE_FORMAT(create_time,'%Y-%m-%d')<={1}", "2021-01-10", "2021-01-18");
wrapper.likeRight("title", "玩转");
List guangGaos = guangGaoMapper.selectList(wrapper);
}
/*
查询操作 QueryWrapper,演示多条件 is not null , between
*** 注意：只要是用匿名内部类，生成的sql 是个组合，要用括号()起来的 ***
WHERE (create_time IS NOT NULL AND title = ?
OR
(id BETWEEN ? AND ?))
*/
@Test
void test_8() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.isNotNull("create_time");
wrapper.eq("title", "森岛帆高");
wrapper.or(new Consumer>() {
@Override
public void accept(QueryWrapper queryWrapper) {
queryWrapper.between("id", 60, 63);
}
});
List guangGaos = guangGaoMapper.selectList(wrapper);
}
/*
查询操作 QueryWrapper
*** 注意：只要是用匿名内部类，生成的sql 是个组合，要用括号()起来的 ***
WHERE title LIKE ?
AND
(create_time IS NOT NULL
OR
price = ?)
*/
@Test
void test_9() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.likeRight("title", "玩转");
wrapper.and(new Consumer>() {
@Override
public void accept(QueryWrapper queryWrapper) {
queryWrapper.isNotNull("create_time");
queryWrapper.or();
queryWrapper.eq("price", 150);
}
});
List guangGaos = guangGaoMapper.selectList(wrapper);
}
/*
wrapper 分页查询
WHERE (id > 20) LIMIT (2-1)*5 ,5
*/
@Test
void test_11() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.gt("id", 20);
//第1页，每页2条
Page page = new Page<>(2, 5);
IPage bannerDOIPage = guangGaoMapper.selectPage(page, wrapper);
System.out.println("总条数" + bannerDOIPage.getTotal());
System.out.println("总页数" + bannerDOIPage.getPages());
//获取当前数据
System.out.println(bannerDOIPage.getRecords());
}
/*
查询（根据 columnMap 条件）
FROM guanggao WHERE id = 67 AND title = 'a'
*/
@Test
void test_18() {
HashMap map = new HashMap<>();
map.put("id", 67);
map.put("title", "a");
List guangGaos = guangGaoMapper.selectByMap(map);
}
/*
根据 Wrapper 条件，结果只能有一条，否则会报错
FROM guanggao WHERE (id = 63)
*/
@Test
void test_19() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.eq("id", 63);
GuangGao guangGao = guangGaoMapper.selectOne(wrapper);
}
/*
根据 Wrapper 条件，查询总记录数
SELECT COUNT( * ) FROM guanggao WHERE (id > 25)
*/
@Test
void test_20() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.gt("id", 25);
Integer integer = guangGaoMapper.selectCount(wrapper);
System.out.println(integer);
}
/*
根据 Wrapper 条件，查询全部记录
SELECT price,count(price) as priceCount FROM guanggao GROUP BY price
[{price=55, priceCount=3}, {price=66, priceCount=3}, {price=77, priceCount=3}]
*/
@Test
void test_21() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.select("price", "count(price) as priceCount");
wrapper.groupBy("price");
List> maps = guangGaoMapper.selectMaps(wrapper);
System.out.println(maps);
}
/*
根据 Wrapper 条件，查询全部记录
注意： 只返回第一个字段的值
SELECT title,cover_img,price FROM guanggao WHERE (id = 45 OR id IN (46, 47))
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*/
@Test
void test_22() {
QueryWrapper wrapper = new QueryWrapper<>();
wrapper.select("title", "cover_img", "price");
wrapper.eq("id", 45);
wrapper.or();
wrapper.in("id", 46, 47);
List