官网地址：MyBatis-Plus 🚀 为简化开发而生

相关pom

<dependency>
    <groupId>com.baomidou</groupId>
    <artifactId>mybatis-plus-boot-starter</artifactId>
    <version>3.5.7</version>
</dependency>
 <dependency>
     <groupId>com.baomidou</groupId>
     <artifactId>mybatis-plus</artifactId>
     <version>3.5.7</version>
</dependency>

使用basemapper报错：org.apache.ibatis.binding.BindingException:

修改  MyBatisConfig 中SqlSessionFactoryBean为MybatisSqlSessionFactoryBean

        final MybatisSqlSessionFactoryBean sessionFactory = new MybatisSqlSessionFactoryBean();
        sessionFactory.setDataSource(dataSource);
        sessionFactory.setTypeAliasesPackage(typeAliasesPackage);
        sessionFactory.setMapperLocations(resolveMapperLocations(StringUtils.split(mapperLocations, ",")));
        sessionFactory.setConfigLocation(new DefaultResourceLoader().getResource(configLocation));

其他使用

@Mapper
public interface SysDischargeApplyRecordMapper extends BaseMapper<SysDischargeApplyRecord> {
}

public interface SysDischargeApplyRecordService extends IService<SysDischargeApplyRecord> {
}

@Service
public class SysDischargeApplyRecordImpl extends ServiceImpl<SysDischargeApplyRecordMapper, SysDischargeApplyRecord> implements SysDischargeApplyRecordService {
}

//条件嵌套  sql: del_flag=0 and (sex like search or theme like search or name like search  )
        QueryWrapper<EmailManage> queryWrapper=new QueryWrapper();
        queryWrapper.eq("del_flag","0");
        if(StringUtils.isNotBlank(emailManageVo.getSearch())){
            queryWrapper.and(i->i.like("sex",emailManageVo.getSearch()).
                    or().like("theme",emailManageVo.getSearch())
                    .or().like("name",emailManageVo.getSearch());
        }

其他

//抽取集合内一个属性
List<String> orderNoList=list.stream().map(Order::getOrderNo).collect(Collectors.toList());
//按一个属性抽取数据集
List<Student> resultList =list.stream().filter(student -> Objects.equals(student.getSex(),"女")).collect(Collectors.toList());
//抽取集合内一个属性 并去重
List<String> listNew = list.stream().map(Student::getName).distinct().collect(Collectors.toList());
//集合两个属性凑成map
Map<String, Student> studentMap = list.stream().collect(Collectors.toMap(Student::getName, student -> student));
//抽取集合内一个属性 去空
List<String> stringList = list.stream().map(s -> s.getName()).filter(s -> !s.isEmpty()).collect(Collectors.toList());
//对list一个属性分组
Map<String, List<Student>> map = students.stream().collect(Collectors.groupingBy(Student::getSex));
//map排序
//对value正向排序
Map<String, Integer> sortedByCount = wordCounts.entrySet().stream().sorted(Map.Entry.comparingByValue())
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));

//对value反向排序
Map<String, Integer> sortedByCount1 = wordCounts.entrySet().stream().sorted((Map.Entry.<String, Integer>comparingByValue().reversed()))
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue, (e1, e2) -> e1, LinkedHashMap::new));

//对key正向排序
Map<String, Integer> result1 = unsortMap.entrySet().stream().sorted(Map.Entry.comparingByKey())
.collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue,(oleValue, newValue) -> oleValue, LinkedHashMap::new));
方式二
Map<String, Integer> result2 = new LinkedHashMap<>();
unsortMap.entrySet().stream().sorted(Map.Entry.comparingByKey())
.forEachOrdered(x -> result2.put(x.getKey(), x.getValue()));


list排序
// 按照List中对象的id属性升序
list.sort(Comparator.comparing(User::getId))
// 按照List中对象的id属性降序
list.sort(Comparator.comparing(User::getId).reversed());
// 多个条件升序
list.sort(Comparator.comparing(User::getId).thenComparing(User::getDeId));
// id升序，deId降序
list.sort(Comparator.comparing(User::getId).reversed().thenComparing(User::getDeId));

//list 属性最大值
SchedulePlanning end = schedulePlannings.stream().max(Comparator.comparing(SchedulePlanning::getScheduledEndTime)).get();
//list 属性最小值
SchedulePlanning start = schedulePlannings.stream().min(Comparator.comparing(SchedulePlanning::getScheduledStartTime)).get();
//list最大值
Double max = taxList.stream().max(Comparator.comparing(Double::doubleValue)).get();