MPJ多表连表查询(包含分页)

MPJ是mybatis plus join 的缩写，以前写多表查询时，一般都是写在配置文件，现在mybatis plus join 完全可以解放写xml文件，功能十分强大。
上代码，本文涉及五张表，连表查询从各个表拿出所需字段输出一条记录。
Device表：

device_category表

device_image表：

device_status表：

producer表：

项目工程结构：

1.首先引入MPJ插件

<dependency>            <groupId>com.github.yulichang</groupId>            <artifactId>mybatis-plus-join</artifactId>            <version>1.3.0</version>        </dependency>

配置config

@Configurationpublic class MySqlInjector extends MPJSqlInjector {    @Override    public List<AbstractMethod> getMethodList(Class<?> mapperClass) {        //将原来的保持        List<AbstractMethod> methodList = super.getMethodList(mapperClass);        //多表查询sql注入 从连表插件里移植过来的        methodList.add(new SelectJoinOne());        methodList.add(new SelectJoinList());        methodList.add(new SelectJoinPage());        methodList.add(new SelectJoinMap());        methodList.add(new SelectJoinMaps());        methodList.add(new SelectJoinMapsPage());        return methodList;    }}

mapper包

dto:

@Data@Builder@AllArgsConstructor@NoArgsConstructor@Accessors(chain = true)@ApiModel(value = "DeviceInfoDto", description = "")public class DeviceInfoDto implements Serializable {    private static final long serialVersionUID = 1L;        @ApiModelProperty("设备id")    private Long id;        @ApiModelProperty("设备名称")    private String deviceName;        @ApiModelProperty("设备序列号")    private String serialNum;        @ApiModelProperty("设备型号")    private String modelNum;        @ApiModelProperty("类别名称")    private String categoryName;        @ApiModelProperty("设备产商")    private String producer;        @ApiModelProperty("设备状态值")    private String statusValue;        @ApiModelProperty("图片地址")    private String imageUrl;}

主启动：

测试代码：

 @Test    void testJoin(){        String status = "启动";               IPage<DeviceInfoDto> page = deviceMapper.selectJoinPage(new Page<>(1,3)                ,DeviceInfoDto.class,MPJWrappers.<Device>lambdaJoin().                        select(Device::getId,Device::getDeviceName,Device::getSerialNum,Device::getModelNum).                        select(DeviceCategory::getCategoryName).                        select(Producer::getProducer).                        select(DeviceStatus::getStatusValue).                        select(DeviceImage::getImageUrl).                        leftJoin(DeviceCategory.class,on-> on    .eq(Device::getCategoryId,DeviceCategory::getId))                        .leftJoin(Producer.class,on-> on    .eq(Device::getProducerId,Producer::getId))                        .leftJoin(DeviceStatus.class,on-> on    .eq(Device::getStatusId,DeviceStatus::getId))                        .leftJoin(DeviceImage.class,on->on.    eq(Device::getId,DeviceImage::getDeviceId))                        .eq(Device::getCompanyId,1L)                        .eq(!Objects.isNull(status),DeviceStatus::getStatusValue,status));        page.getRecords().forEach(System.out::println);    }

运行结果：

来源地址：https://blog.csdn.net/weixin_46649945/article/details/129408368