MybatisPlus中静态工具DB的实现

@Test
void testDbGet() {
    User user = Db.getById(1L, User.class);
    System.out.println(user);
}

@Test
void testDbList() {
    // 利用Db实现复杂条件查询
    List<User> list = Db.lambdaQuery(User.class)
            .like(User::getUsername, "o")
            .ge(User::getBalance, 1000)
            .list();
    list.forEach(System.out::println);
}

@Test
void testDbUpdate() {
    Db.lambdaUpdate(User.class)
            .set(User::getBalance, 2000)
            .eq(User::getUsername, "Rose");
}

package com.itheima.mp.domain.vo;

import io.swagger.annotations.ApiModel;
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;

@Data
@ApiModel(description = "收货地址VO")
public class AddressVO{

    @ApiModelProperty("id")
    private Long id;

    @ApiModelProperty("用户ID")
    private Long userId;

    @ApiModelProperty("省")
    private String province;

    @ApiModelProperty("市")
    private String city;

    @ApiModelProperty("县/区")
    private String town;

    @ApiModelProperty("手机")
    private String mobile;

    @ApiModelProperty("详细地址")
    private String street;

    @ApiModelProperty("联系人")
    private String contact;

    @ApiModelProperty("是否是默认 1默认 0否")
    private Boolean isDefault;

    @ApiModelProperty("备注")
    private String notes;
}

@Data
@ApiModel(description = "用户VO实体")
public class UserVO {

    @ApiModelProperty("用户id")
    private Long id;

    @ApiModelProperty("用户名")
    private String username;

    @ApiModelProperty("详细信息")
    private UserInfo info;

    @ApiModelProperty("使用状态（1正常 2冻结）")
    private UserStatus status;

    @ApiModelProperty("账户余额")
    private Integer balance;

    @ApiModelProperty("用户的收货地址")
    private List<AddressVO> addresses;
}

@GetMapping("/{id}")
@ApiOperation("根据id查询用户")
public UserVO queryUserById(@PathVariable("id") Long userId){
    // 基于自定义service方法查询
    return userService.queryUserAndAddressById(userId);
}

import com.baomidou.mybatisplus.extension.service.IService;
import com.itheima.mp.domain.po.User;
import com.itheima.mp.domain.vo.UserVO;

public interface IUserService extends IService<User> {
    void deduct(Long id, Integer money);

    UserVO queryUserAndAddressById(Long userId);
}

	@Override
	public UserVO queryUserAndAddressById(Long Id) {
		// 1.查询用户
		User user = this.getById(Id);
		if (user == null || user.getStatus()==UserStatus.FROZEN) {
			throw new RuntimeException("用户状态异常!");
		}
		// 2.查询收货地址
		List<Address> addresses = Db.lambdaQuery(Address.class)
				.eq(Address::getUserId, Id)
				.list();
		// 3.处理vo
		UserVO userVO = BeanUtil.copyProperties(user, UserVO.class);
		//转地址VO
		if (CollUtil.isNotEmpty(addresses)){
			userVO.setAddresses(BeanUtil.copyToList(addresses,AddressVO.class));
		}
		return userVO;
	}

	@GetMapping
	@ApiOperation("根据id批量查询用户接口")
	public List<UserVO> queryUserByIds(@ApiParam("用户id集合") @RequestParam("ids") List<Long> ids){
		return userService.queryUserAndAddressByIds(ids);
	}

	@Override
	public List<UserVO> queryUserAndAddressByIds(List<Long> ids) {
		// 1.查询用户
		List<User> users = listByIds(ids);
		if (CollUtil.isEmpty(users)) {
			return Collections.emptyList();
		}
		// 2.查询地址
		// 2.1.获取用户id集合
		List<Long> userIds = users.stream().map(User::getId).collect(Collectors.toList());
		// 2.2.根据用户id查询地址
		List<Address> addresses = Db.lambdaQuery(Address.class).in(Address::getUserId, userIds).list();
		// 2.3.转换地址VO
		List<AddressVO> addressVOList = BeanUtil.copyToList(addresses, AddressVO.class);
		// 2.4.用户地址集合分组处理，相同用户的放入一个集合（组）中
		Map<Long, List<AddressVO>> addressMap = new HashMap<>(0);
		if(CollUtil.isNotEmpty(addressVOList)) {
			addressMap = addressVOList.stream().collect(Collectors.groupingBy(AddressVO::getUserId));
		}
		// 3.转换VO返回
		List<UserVO> list = new ArrayList<>(users.size());
		for (User user : users) {
			// 3.1.转换User的PO为VO
			UserVO vo = BeanUtil.copyProperties(user, UserVO.class);
			list.add(vo);
			// 3.2.转换地址VO
			vo.setAddresses(addressMap.get(user.getId()));
		}
		return list;
	}