条件构造器queryWrapper和updateWrapper

1.环境：springboot + mybatis plus

2.构造器解析

　1). QueryWrapper： Entity 对象封装操作类

　2). UpdateWrapper ： Update 条件封装，用于Entity对象更新操作

　2). 条件构造器使用中的各个方法格式和说明

　　

 3.示例

　1）UpdateWrapper 实例 

UpdateWrapper<CarEntity> ew = new UpdateWrapper<>();
ew.lambda().set(CarEntity::getTerminalcode,null)
        .set(CarEntity::getTerminalid,null)
        .set(CarEntity::getModifiedon,LocalDateTime.now())
        .eq(CarEntity::getCarid,cEntity.getCarid());
this.carMapper.update(null, ew);

2）QueryWrapper 实例一

CarEntity Entity = this.carMapper.selectOne(new QueryWrapper<CarEntity>().lambda().eq(CarEntity::getTerminalid, tEntity.getTerminalid()));

3）QueryWrapper 实例二

int count = this.baseMapper.selectCount(new QueryWrapper<DataprivilegeEntity>()
        .lambda()
        .eq(DataprivilegeEntity::getDataprivilegetype, 1)
        .eq(DataprivilegeEntity::getDataprivilegeid, car)
        .eq(DataprivilegeEntity::getPrincipalid, request.getStationid()));

4）QueryWrapper 实例二

QueryWrapper<CarEntity> queryWrapper = new QueryWrapper<>();
queryWrapper.lambda().select(CarEntity::getCarid)
        .notInSql(CarEntity::getCarid,
                "select dataprivilegeid from sysdataprivilege where principaltype = 1 and dataprivilegetype = 1 and datatype = 1 and principalid = '" + request.getStationid() + "'");
List<Object> list = carService.getBaseMapper().selectObjs(queryWrapper);
list.forEach(p -> {
    DataprivilegeEntity entity = new DataprivilegeEntity();
    entity.setDataprivilegetype(1);
    entity.setDatatype(1);
    entity.setPrincipaltype(1);
    entity.setPrincipalid(request.getStationid());
    entity.setDataprivilegeid(p.toString());
    entity.setSysdataprivilegeid(UUID.randomUUID().toString());
    this.baseMapper.insert(entity);