1 序

mapstruct.png

MapStruct是一個屬性映射工具糟秘，只需要使用@Mapper注解標(biāo)注的映射接口富俄。MapStruct就會自動生成實現(xiàn)這個映射接口的實現(xiàn)類旦签，避免了復(fù)雜繁瑣的映射實現(xiàn)。MapStruct官網(wǎng)地址： http://mapstruct.org/吮炕。

2 準(zhǔn)備工作

2.1 定義映射示例Bean

• 定義Mode Bean

package com.eugeneheen.mapstruct.api.model;

import com.fasterxml.jackson.annotation.JsonFormat;
import lombok.Data;
import java.time.LocalDateTime;

@Data
public class UserModel {
    private Long id;

    private String name;

    private String phone;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    LocalDateTime createTm;

    @JsonFormat(pattern = "yyyy-MM-dd HH:mm:ss")
    LocalDateTime updateTm;
}

• 定義Do Bean

package com.eugeneheen.mapstruct.dao.dataobject;

import lombok.Data;
import javax.persistence.*;
import java.time.LocalDateTime;

@Data
@Entity(name = "t_user")
public class UserDo {

    @Id
    @GeneratedValue(strategy = GenerationType.IDENTITY)
    private Long id;

    @Column
    private String name;

    @Column
    private String phone;

    @Column(name = "create_tm")
    LocalDateTime createTm;

    @Column(name = "update_tm")
    LocalDateTime updateTm;
}

2.2 示例使用的相關(guān)依賴

• Lombok

<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.18.22</version>
    <optional>true</optional>
</dependency>

• MapStruct官方依賴

<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct</artifactId>
    <version>1.4.2.Final</version>
</dependency>
<dependency>
    <groupId>org.mapstruct</groupId>
    <artifactId>mapstruct-processor</artifactId>
    <version>1.4.2.Final</version>
</dependency>
<dependency>
    <groupId>org.mapstruct.extensions.spring</groupId>
    <artifactId>mapstruct-spring-annotations</artifactId>
    <version>0.1.0</version>
</dependency>

• MapStruct第三方依賴

<dependency>
     <groupId>io.github.zhaord</groupId>
     <artifactId>mapstruct-spring-plus-boot-starter</artifactId>
     <version>1.0.1.RELEASE</version>
</dependency>

3 示例

3.1 關(guān)于依賴

3.1.1 Maven

• SpringBoot單模塊項目：直接在POM文件加入相關(guān)依賴即可。
• SpringBoot多模塊項目
  • 打包的模塊访得，POM文件加入以下依賴：

  <build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <encoding>UTF-8</encoding>
            </configuration>
        </plugin>
        <plugin>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-maven-plugin</artifactId>
            <version>2.4.1</version>
            <configuration>
                <mainClass>com.eugeneheen.mapstruct.MapStructApplication</mainClass>
                <skip>false</skip>
                <layers>
                <enabled>true</enabled>
                </layers>
                <excludes>
                <!-- 打包的時候忽略lombok龙亲，解決生成了maptruct的實現(xiàn)類陕凹，但該類只創(chuàng)建了對象，沒有進行賦值 -->
                <exclude>
                    <groupId>org.projectlombok</groupId>
                    <artifactId>lombok</artifactId>
                </exclude>
                </excludes>
            </configuration>
            <executions>
                <execution>
                <id>repackage</id>
                <goals>
                    <goal>repackage</goal>
                </goals>
                </execution>
            </executions>
        </plugin>
    </plugins>
  </build>
  

  • 定義映射接口的模塊鳄炉，POM文件加入以下依賴：

    <dependencies>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct</artifactId>
            <version>1.4.2.Final</version>
        </dependency>
        <dependency>
            <groupId>org.mapstruct</groupId>
            <artifactId>mapstruct-processor</artifactId>
            <version>1.4.2.Final</version>
        </dependency>
        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.22</version>
            <optional>true</optional>
        </dependency>
    </dependencies>
    <build>
        <plugins>
            <plugin>
                <groupId>org.apache.maven.plugins</groupId>
                <artifactId>maven-compiler-plugin</artifactId>
                <version>3.8.1</version>
                <configuration>
                    <source>1.8</source>
                    <target>1.8</target>
                    <encoding>UTF-8</encoding>
                    <annotationProcessorPaths>
                        <!-- 此處杜耙，lombok依賴一定要放在，Mapstruct-processor依賴之前拂盯。否則佑女，生成了maptruct的實現(xiàn)類，但該類只創(chuàng)建了對象谈竿，沒有進行賦值 -->
                        <path>
                            <groupId>org.projectlombok</groupId>
                            <artifactId>lombok</artifactId>
                            <version>1.18.22</version>
                        </path>
                        <path>
                            <groupId>org.mapstruct</groupId>
                            <artifactId>mapstruct-processor</artifactId>
                            <version>1.4.2.Final</version>
                        </path>
                    </annotationProcessorPaths>
                </configuration>
            </plugin>
        </plugins>
    </build>
    

3.1.2 Gradle

• version >= 4.6

dependencies {
    implementation 'org.mapstruct:mapstruct:1.4.2.Final'
    annotationProcessor 'org.mapstruct:mapstruct-processor:1.4.2.Final'
}

• version < 4.6

plugins {
    id 'net.ltgt.apt' version '0.21'
}
dependencies {
    compile 'org.mapstruct:mapstruct:1.4.2.Final'
    apt 'org.mapstruct:mapstruct-processor:1.4.2.Final'
}

3.2 基礎(chǔ)使用示例

• 定義映射接口

package com.eugeneheen.mapstruct.api.struct;

import com.yongyou.eshs.api.model.UserModel;
import com.yongyou.eshs.dao.dataobject.UserDo;
import org.mapstruct.Mapper;

@Mapper
public interface IUserStruct {
    IUserStruct INSTANCE = Mappers.getMapper( IUserStruct.class );
    
    UserDo modelToDo(UserModel userModel);
    UserModel doToModel(UserDo user);
}

• 在Service中使用

public interface IUserService {
    UserModel findById(Long id);
}

@Service
public class UserServiceImpl implements IUserService {

    @Autowired
    private IUserRepository userRepository;

    @Override
    public UserModel findById(Long id) {
        UserDo user = this.userRepository.getOne(id);
        // 此處团驱，由于映射定義未使用Spring注入，所以使用常量獲實例再調(diào)用映射方法
        return IUserStruct.INSTANCE.toModel(user);
    }
}

3.3 注入到Spring的使用示例

• 定義映射接口

  package com.eugeneheen.mapstruct.api.struct;
  
  import com.yongyou.eshs.api.model.UserModel;
  import com.yongyou.eshs.dao.dataobject.UserDo;
  import org.mapstruct.Mapper;
  
   // 使用@Mapper注解的componentModel屬性值制定為Spring榕订，實現(xiàn)Spring注入
  @Mapper(componentModel = "spring")
  public interface IUserStruct {
      UserDo modelToDo(UserModel userModel);
      UserModel doToModel(UserDo user);
  }

• 在Service中使用

public interface IUserService {
    UserModel findById(Long id);
}

@Service
public class UserServiceImpl implements IUserService {

    @Autowired
    private IUserRepository userRepository;

    // 此處店茶，注入由Spring管理的映射實現(xiàn)
    @Autowired
    private IUserStruct userStruct;

    @Override
    public UserModel findById(Long id) {
        UserDo user = this.userRepository.getOne(id);
        return this.userStruct.toModel(user);
    }
}

3.4 使用Spring擴展依賴的使用示例

待續(xù)......

4 常見問題

4.1 Maven構(gòu)建出現(xiàn)生成了MapStruct的實現(xiàn)類，但該類只創(chuàng)建了對象劫恒，沒有進行賦值的問題

• 定義映射接口的模塊/工程贩幻，maven-compiler-plugin插件，配置lombok-mapstruct-binding依賴两嘴，且依賴版本由0.1.0升級到0.2.0

<dependencies>
    <dependency>
        <groupId>org.mapstruct</groupId>
        <artifactId>mapstruct</artifactId>
        <version>1.4.2.Final</version>
    </dependency>
    <dependency>
        <groupId>org.mapstruct</groupId>
        <artifactId>mapstruct-processor</artifactId>
        <version>1.4.2.Final</version>
    </dependency>
    <dependency>
        <groupId>org.projectlombok</groupId>
        <artifactId>lombok</artifactId>
        <version>1.18.22</version>
        <optional>true</optional>
    </dependency>
</dependencies>
<build>
    <plugins>
        <plugin>
            <groupId>org.apache.maven.plugins</groupId>
            <artifactId>maven-compiler-plugin</artifactId>
            <version>3.8.1</version>
            <configuration>
                <source>1.8</source>
                <target>1.8</target>
                <encoding>UTF-8</encoding>
                <annotationProcessorPaths>
                    <!-- 此處丛楚，lombok依賴一定要放在，Mapstruct-processor依賴之前憔辫。否則趣些，生成了maptruct的實現(xiàn)類，但該類只創(chuàng)建了對象贰您，沒有進行賦值 -->
                    <path>
                        <groupId>org.projectlombok</groupId>
                        <artifactId>lombok</artifactId>
                        <version>1.18.22</version>
                    </path>
                    <path>
                        <groupId>org.projectlombok</groupId>
                        <artifactId>lombok-mapstruct-binding</artifactId>
                        <!-- 如果是0.1.0 有可能出現(xiàn)生成了MapStruct的實現(xiàn)類坏平，但該類只創(chuàng)建了對象，沒有進行賦值 -->
                        <version>0.2.0</version>
                    </path>
                    <path>
                        <groupId>org.mapstruct</groupId>
                        <artifactId>mapstruct-processor</artifactId>
                        <version>1.4.2.Final</version>
                    </path>
                </annotationProcessorPaths>
            </configuration>
        </plugin>
    </plugins>
</build>

• 多項目打包時锦亦，在父項目/打包模塊的POM中配置spring-boot-maven-plugin插件時舶替，排除``依賴。詳細配置見3.1.1章節(jié)杠园，SpringBoot多模塊項目配置

5 MapStruct與各種BeanUtil性能比較

測試數(shù)據(jù)僅供參考顾瞪，根據(jù)不同主機配置均有不同，單此處數(shù)據(jù)也能客觀表現(xiàn)性能