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Java高性能实体类转换工具MapStruct的使用教程详解

2024-03-24 10:02:06 作者：EvenBoy

MapStruct 是一个代码生成器,它基于约定优于配置的方法,极大地简化了 Java bean 类型之间的映射实现,本文主要介绍了MapStruct的具体使用以及如何进行实体类转换,感兴趣的可以了解下

MapStruct

它是什么?

MapStruct 是一个代码生成器，它基于约定优于配置的方法，极大地简化了 Java bean 类型之间的映射实现。

生成的映射代码使用普通的方法调用，因此速度快、类型安全且易于理解。

为什么？

多层应用程序通常需要在不同的对象模型（例如实体和 DTO）之间进行映射。编写这样的映射代码是一项乏味且容易出错的任务。MapStruct 旨在通过尽可能地自动化来简化这项工作。

与其他映射框架相比，MapStruct 在编译时生成 bean 映射，这确保了高性能，允许快速的开发人员反馈和彻底的错误检查。

如何？

MapStruct 是一个注解处理器，它插入到 Java 编译器中，可用于命令行构建（Maven、Gradle 等）以及您首选的 IDE。

MapStruct 使用合理的默认值，但在配置或实现特殊行为时会采取措施。

使用场景

1、数据库中的字段和你对接的A部门、B部门的入参字段不一致的情况。

2、涉及到一些入参和出参值的转换比如：性别、日期等。

使用教程

1、引入pom.xml

     <!--mapStruct依赖-->
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>1.3.1.Final</version>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>1.3.1.Final</version>
            <scope>provided</scope>
        </dependency>

2、入参(每个部门的入参可能不太一样)

package com.lezu.springboot.common.dto.param;
 
import io.swagger.annotations.ApiModelProperty;
import lombok.Data;
 
/**
 * @author LianJiaYu
 * @date 2022/9/1 14:09
 */
@Data
public class UserInfoParam {
 
    @ApiModelProperty(value = "用户账号")
    private String account;
 
    @ApiModelProperty(value = "性别")
    private String gender;
 
    @ApiModelProperty(value = "密码")
    private String password;
 
    @ApiModelProperty(value = "出生日期")
    private Long birthday;
 
    @ApiModelProperty(value = "验证码captchaId")
    private String captchaId;
 
    @ApiModelProperty(value = "昵称")
    private String name;
 
    @ApiModelProperty(value = "验证码")
    private String code;
 
}

3、对应数据库中的字段

package com.lezu.springboot.common.dto.in;
 
import com.lezu.springboot.common.Page;
import io.swagger.annotations.ApiModelProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
 
import javax.validation.constraints.NotNull;
import java.io.Serializable;
import java.util.Date;
 
/**
 * @Author LianJiaYu
 * @Date 2021/4/4 22:06
 * @Version 1.0
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class InUserInfoDto extends Page implements Serializable {
 
    private static final long serialVersionUID = 5755742614532104337L;
 
    @ApiModelProperty(value = "用户账号")
    @NotNull(message = "用户名不能为空")
    private String username;
 
    @ApiModelProperty(value = "性别")
    private Integer gender;
 
    @ApiModelProperty(value = "密码")
    @NotNull(message = "密码不能为空")
    private String password;
 
    @ApiModelProperty(value = "出生日期")
    private Date birthday;
 
    @ApiModelProperty(value = "验证码captchaId")
    private String captchaId;
 
    @ApiModelProperty(value = "昵称")
    private String name;
 
    @ApiModelProperty(value = "验证码")
    private String code;
 
    @ApiModelProperty(value = "默认状态")
    private String defaultStatus;
 
}

4、定义工厂

package com.lezu.springboot.common.dto.Interface;
 
import com.lezu.springboot.common.ListResult;
import com.lezu.springboot.common.conversion.DataConversionWorker;
import com.lezu.springboot.common.conversion.EnumConversionWorker;
import com.lezu.springboot.common.dto.in.InUserInfoDto;
import com.lezu.springboot.common.dto.out.OutUserInfoDto;
import com.lezu.springboot.common.dto.param.UserInfoParam;
import com.lezu.springboot.common.dto.result.UserInfoResult;
import org.mapstruct.Mapper;
import org.mapstruct.Mapping;
import org.mapstruct.Mappings;
import org.mapstruct.factory.Mappers;
 
/**
 * @author LianJiaYu
 * @date 2022/9/1 14:04
 */
@Mapper(uses = {DataConversionWorker.class, EnumConversionWorker.class})
public interface UserConvert {
    UserConvert INSTANCE = Mappers.getMapper(UserConvert.class);
 
 
    //入参转换
    @Mappings({
            @Mapping(source = "account", target = "username"),
            @Mapping(source = "gender", target = "gender", qualifiedByName = "setGenderToInteger"),
            @Mapping(source = "birthday", target = "birthday", qualifiedByName = "getBirthdayToDate"),
            @Mapping(target = "defaultStatus", defaultValue = "success"),
    })
    InUserInfoDto userInfoConvert(UserInfoParam param);
 
 
    //出参转换
    @Mappings({
            @Mapping(source = "username", target = "account"),
            @Mapping(source = "gender", target = "gender", qualifiedByName = "setGenderToString"),
            @Mapping(source = "birthday", target = "birthday", qualifiedByName = "getBirthdayToLong"),
    })
    UserInfoResult userInfoResultConvert(OutUserInfoDto dto);
 
    ListResult<UserInfoResult> listUserInfoResultConvert(ListResult<OutUserInfoDto> list);
 
 
}

5、定义时间戳转换日期和日期转时间戳方法

package com.lezu.springboot.common.conversion;
 
import cn.hutool.core.date.DateUtil;
import org.mapstruct.Named;
 
import java.util.Date;
 
/**
 * @author LianJiaYu
 * @date 2022/9/2 15:08
 */
//@Component
public class DataConversionWorker {
 
    @Named("getBirthdayToDate")
    public Date getBirthdayToDate(Long birthday) {
        if (birthday == null) {
            return null;
        }
        return DateUtil.date(birthday);
    }
 
    @Named("getBirthdayToLong")
    public Long getBirthdayToLong(Date birthday) {
        if (birthday == null) {
            return null;
        }
        return birthday.getTime();
    }
}

6、定义性别转换方法

package com.lezu.springboot.common.conversion;
 
import com.lezu.springboot.enums.UserGenderEnum;
import org.mapstruct.Named;
import org.springframework.stereotype.Component;
 
/**
 * @author LianJiaYu
 * @date 2022/9/2 15:08
 */
//@Component
public class EnumConversionWorker {
 
    @Named("setGenderToInteger")
    public Integer setGenderToInteger(String type) {
        return UserGenderEnum.getByType(type).getCode();
    }
 
    @Named("setGenderToString")
    public Integer setGenderToString(Integer code) {
        return UserGenderEnum.getByCode(code).getCode();
    }
 
}

7、性别转换枚举

package com.lezu.springboot.enums;
 
/**
 * @author LianJiaYu
 * @date 2022/9/16 10:10
 */
public enum UserGenderEnum {
    FEMALE(0, "female"),
    MALE(1, "male"),
    UNKNOWN(2, "unknown"),
    ;
 
 
    private Integer code;
    private String type;
 
    UserGenderEnum(Integer code, String type) {
        this.code = code;
        this.type = type;
    }
 
    public Integer getCode() {
        return code;
    }
 
    public String getType() {
        return type;
    }
 
 
    public static UserGenderEnum getByCode(Integer code) {
        for (UserGenderEnum v : UserGenderEnum.values()) {
            if (v.getCode() == code) {
                return v;
            }
        }
        return UNKNOWN;
    }
 
    public static UserGenderEnum getByType(String type) {
        for (UserGenderEnum v : UserGenderEnum.values()) {
            if (v.getType().equals(type)) {
                return v;
            }
        }
        return UNKNOWN;
    }
}

8、编写Controller代码进行测试

package com.lezu.springboot.controller;
 
import com.alibaba.fastjson.JSON;
import com.lezu.springboot.common.ListResult;
import com.lezu.springboot.common.dto.Interface.UserConvert;
import com.lezu.springboot.common.dto.in.InUserInfoDto;
import com.lezu.springboot.common.dto.param.UserInfoParam;
import com.lezu.springboot.common.dto.result.UserInfoResult;
import com.lezu.springboot.enums.ResultEnum;
import com.lezu.springboot.service.UserInfoHandleService;
import io.swagger.annotations.ApiOperation;
import lombok.extern.slf4j.Slf4j;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
 
import java.util.Objects;
 
/**
 * 高性能实体类转换工具MapStruct
 * 类型转换工具
 * @author LianJiaYu
 * @date 2022/9/1 13:57
 */
@RestController
@RequestMapping("/mapstruct")
@Slf4j
public class MapstructController {
 
    @Autowired
    private UserInfoHandleService userInfoHandleService;
 
    @ApiOperation("类型转换")
    @PostMapping("/login")
    public ListResult<UserInfoResult> login(UserInfoParam params) {
        ListResult listResult = new ListResult();
        if (Objects.isNull(params)) {
            return listResult.build(ResultEnum.PARAM_ERROR.getCode(), ResultEnum.PARAM_ERROR.getMsg());
        }
        //入参-日志
        log.info("params:" + JSON.toJSONString(params));
 
        //入参-参数转换
        InUserInfoDto inDto = UserConvert.INSTANCE.userInfoConvert(params);
        log.info("inDto:" + JSON.toJSONString(inDto));
 
 
        //出参-参数转换
        listResult = UserConvert.INSTANCE.outDtoToResult(userInfoHandleService.listByPage(inDto));
        log.info("listResult:" + JSON.toJSONString(listResult));
        return listResult;
    }
}

Service层

   @Override
    public ListResult listByPage(InUserInfoDto inDto) {
        ListResult listResult = new ListResult();
        LambdaQueryWrapper<UserInfo> wrapper = Wrappers.lambdaQuery();
        if (StrUtil.isNotBlank(inDto.getUsername())) {
            wrapper.like(UserInfo::getUsername, inDto.getUsername());
        }
        int pageNum = inDto.getPageNum();
        int pageSize = inDto.getPageSize() == 0 ? 10 : inDto.getPageSize();
 
        IPage<UserInfo> page = new Page<>(pageNum, pageSize);
        userInfoService.page(page, wrapper);
        List<OutUserInfoDto> list = page.getRecords().stream().map(v -> {
            OutUserInfoDto dto = new OutUserInfoDto();
            BeanUtils.copyProperties(v, dto);
            return dto;
        }).collect(Collectors.toList());
 
 
        return listResult.ok(list, page.getTotal());
    }

OutUserInfo实体类

package com.lezu.springboot.common.dto.out;
 
import com.baomidou.mybatisplus.annotation.IdType;
import com.baomidou.mybatisplus.annotation.TableId;
import com.baomidou.mybatisplus.annotation.TableLogic;
import io.swagger.annotations.ApiModelProperty;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
 
import java.io.Serializable;
 
/**
 * @Author LianJiaYu
 * @Date 2021/4/4 22:06
 * @Version 1.0
 */
@Data
@AllArgsConstructor
@NoArgsConstructor
public class OutUserInfoDto implements Serializable {
 
    private static final long serialVersionUID = 6248490570574329534L;
 
    @ApiModelProperty(value = "主键id")
    @TableId(value = "id", type = IdType.AUTO)
    private Integer id;
 
    @ApiModelProperty(value = "用户账号")
    private String username;
 
    @ApiModelProperty(value = "性别")
    private String gender;
 
    @ApiModelProperty(value = "密码")
    private String password;
 
    @ApiModelProperty(value = "权限")
    private Integer power;
 
    @ApiModelProperty(value = "昵称")
    private String name;
 
 
 
}

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