MapStruct的使用#

1
/**
2
* Beanutils copyProperties 的反射
3
*/
4
private static void copyProperties(Object source, Object target, Class<?> editable, String... ignoreProperties)
5
            throws BeansException {
6
        // 检查source和target对象是否为null，否则抛运行时异常
7
        Assert.notNull(source, "Source must not be null");
8
        Assert.notNull(target, "Target must not be null");
9
        // 获取target对象的类信息
10
        Class<?> actualEditable = target.getClass();
11
        // 若editable不为null，检查target对象是否是editable类的实例，若不是则抛出运行时异常
12
        // 这里的editable类是为了做属性拷贝时限制用的
13
        // 若actualEditable和editable相同，则拷贝actualEditable的所有属性
14
        // 若actualEditable是editable的子类，则只拷贝editable类中的属性
15
        if (editable != null) {
16
            if (!editable.isInstance(target)) {
17
                throw new IllegalArgumentException("Target class [" + target.getClass().getName() +
18
                        "] not assignable to Editable class [" + editable.getName() + "]");
19
            }
20
            actualEditable = editable;
21
        }
22
        // 获取目标类的所有PropertyDescriptor，getPropertyDescriptors这个方法请看下方
23
        PropertyDescriptor[] targetPds = getPropertyDescriptors(actualEditable);
24
        List<String> ignoreList = (ignoreProperties != null ? Arrays.asList(ignoreProperties) : null);
25

26
        for (PropertyDescriptor targetPd : targetPds) {
27
            // 获取该属性对应的set方法
28
            Method writeMethod = targetPd.getWriteMethod();
29
            // 属性的set方法存在 且 该属性不包含在忽略属性列表中
30
            if (writeMethod != null && (ignoreList == null || !ignoreList.contains(targetPd.getName()))) {
31
                // 获取source类相同名字的PropertyDescriptor, getPropertyDescriptor的具体实现看下方
32
                PropertyDescriptor sourcePd = getPropertyDescriptor(source.getClass(), targetPd.getName());
33
                if (sourcePd != null) {
34
                    // 获取对应的get方法
35
                    Method readMethod = sourcePd.getReadMethod();
36
                    // set方法存在 且 target的set方法的入参是source的get方法返回值的父类或父接口或者类型相同
37
                    // 具体ClassUtils.isAssignable()的实现方式请看下面详解
38
                    if (readMethod != null &&
39
                            ClassUtils.isAssignable(writeMethod.getParameterTypes()[0], readMethod.getReturnType())) {
40
                        try {
41
                            //get方法是否是public的
42
                            if (!Modifier.isPublic(readMethod.getDeclaringClass().getModifiers())) {
43
                                //暴力反射，取消权限控制检查
44
                                readMethod.setAccessible(true);
45
                            }
46
                            //获取get方法的返回值
47
                            Object value = readMethod.invoke(source);
48
                            // 原理同上
49
                            if (!Modifier.isPublic(writeMethod.getDeclaringClass().getModifiers())) {
50
                                writeMethod.setAccessible(true);
51
                            }
52
                            // 将get方法的返回值 赋值给set方法作为入参
53
                            writeMethod.invoke(target, value);
54
                        }
55
                        catch (Throwable ex) {
56
                            throw new FatalBeanException(
57
                                    "Could not copy property '" + targetPd.getName() + "' from source to target", ex);
58
                        }
59
                    }
60
                }
61
            }
62
        }
63
    }

1
      <!--mapStruct依赖 高性能对象映射-->
2
        <dependency>
3
            <groupId>org.mapstruct</groupId>
4
            <artifactId>mapstruct</artifactId>
5
            <version>1.5.5.Final</version>
6
        </dependency>
7
        <!--mapstruct编译-->
8
        <dependency>
9
            <groupId>org.mapstruct</groupId>
10
            <artifactId>mapstruct-processor</artifactId>
11
            <version>1.5.5.Final</version>
12
        </dependency>
13

14

15
    <build>
16
        <plugins>
17
      <!-- 增加mapstruct编译顺序，处理lombok和mapstruct冲突 -->
18
            <plugin>
19
                <groupId>org.apache.maven.plugins</groupId>
20
                <artifactId>maven-compiler-plugin</artifactId>
21
                <version>3.8.1</version>
22
                <configuration>
23
                    <source>1.8</source>
24
                    <target>1.8</target>
25
                    <annotationProcessorPaths>
26
                        <path>
27
                            <groupId>org.mapstruct</groupId>
28
                            <artifactId>mapstruct-processor</artifactId>
29
                            <version>1.5.5.Final</version>
30
                        </path>
31
                        <path>
32
                            <groupId>org.projectlombok</groupId>
33
                            <artifactId>lombok</artifactId>
34
                            <version>1.18.16</version>
35
                        </path>
36
                        <!-- This is needed when using Lombok 1.18.16 and above -->
37
                        <path>
38
                            <groupId>org.projectlombok</groupId>
39
                            <artifactId>lombok-mapstruct-binding</artifactId>
40
                            <version>0.2.0</version>
41
                        </path>
42
                    </annotationProcessorPaths>
43
                </configuration>
44
            </plugin>
45
        </plugins>
46
    </build>

1
@TableName("sb_user")
2
@Data
3
@NoArgsConstructor
4
@AllArgsConstructor
5
@Builder
6
@ToString
7
public class User implements Serializable {
8
    private static final long serialVersionUID = 1L;
9
    @TableId(type = IdType.AUTO)
10
    private Long id;
11
    private String name;
12
    private Long age;
13
    private String email;
14
    private Date createTime;
15
}
16

17
@Data
18
@NoArgsConstructor
19
@AllArgsConstructor
20
@Builder
21
public class UserVo2 {
22
    private String nickName;
23
    private Long age;
24
    private String email;
25
    private Date birthday;
26
    private String createTime;
27
}
28

29
@Mapper
30
public interface UserConverter {
31
    UserConverter INSTANCE = Mappers.getMapper(UserConverter.class);
32
    //1.基本映射
33
    UserVo user2UserVo(User user);
34

35
    @Mapping(target = "nickName", source = "name",defaultValue = "默认")//2.设默认值
36
    @Mapping(target = "birthday" ,expression = "java(new java.util.Date())")//3.使用表达式
37
    @Mapping(target = "createTime",source = "createTime",dateFormat = "yyyy-MM-dd")//4.日期格式化
38
    UserVo2 user2UserVo2(User user);
39

40
    //5.多源映射
41
    @Mapping(target = "birthday", source = "user.createTime")
42
    @Mapping(target = "age",source = "age", numberFormat = "#0.00")//6.数字格式转换
43
    UserVo2 combinationConvrter(User user, UserVo userVo);
44

45
    //7.嵌套映射
46
     @Mapping( target = "name", source = "record.name" )//嵌套映射
47
     @Mapping( target = ".", source = "record" )//直接使用"."的方式将对象中的属性全部映射到当前目标对象
48
     @Mapping(target = "sex", source = "user.gender",qualifiedByName = "getSex"),
49
     Customer  customerDtoToCustomer(CustomerDto customerDto);
50
    //8.逆映射
51
    //9.继承与共享配置
52

53
    //枚举类字段转换
54
    @Named("getSex")
55
    static String genderConverter(Integer code){
56
        for (GenderEnum ge: GenderEnum.values()){
57
            if (ge.getCode().equals(code)){
58
                return ge.getName();
59
            }
60
        }
61
        return null;
62
    }
63
}
64

65
//生成的代码
66
@Generated(
67
    value = "org.mapstruct.ap.MappingProcessor",
68
    date = "2023-12-23T19:24:15+0800",
69
    comments = "version: 1.5.5.Final, compiler: javac, environment: Java 1.8.0_181 (Oracle Corporation)"
70
)
71
public class UserConverterImpl implements UserConverter {
72
  @Override
73
  public UserVo2 combinationConverter(User user, UserVo userVo) {
74
        if ( user == null && userVo == null ) {
75
            return null;
76
        }
77

78
        UserVo2.UserVo2Builder userVo2 = UserVo2.builder();
79

80
        if ( user != null ) {
81
            userVo2.birthday( user.getCreateTime() );
82
            userVo2.age( user.getAge() );
83
            userVo2.sex( UserConverter.genderConverter( user.getGender() ) );
84
            userVo2.nickName( user.getName() );
85
            userVo2.email( user.getEmail() );
86
            userVo2.createTime( dateMapper.asString( user.getCreateTime() ) );
87
        }
88

89
        return userVo2.build();
90
    }
91
}

1
public class DateMapper {
2
    public String asString(Date date) {
3
        return date != null ? new SimpleDateFormat( "yyyy-MM-dd" )
4
            .format( date ) : null;
5
    }
6
    public Date asDate(String date) {
7
        try {
8
            return date != null ? new SimpleDateFormat( "yyyy-MM-dd" )
9
                .parse( date ) : null;
10
        }
11
        catch ( ParseException e ) {
12
            throw new RuntimeException( e );
13
        }
14
    }
15
}
16

17
@Mapper(uses=DateMapper.class)
18
public interface UserConverter {
19
    UserVo user2UserVo(User user);
20
}

1
@Mapper(componentModel = "spring")
2
public interface ModelMapper {
3

4
    ModelMapper INSTANT = Mappers.getMapper(ModelMapper.class);
5

6
    ModelVO conver(Model model);
7

8
}
9
// 直接在类中使用Autowired注入就行了
10
@RestController
11
class MapperSpringController {
12

13
    @Autowired
14
    ModelMapper modelMapper;
15

16
    @GetMapping("/get")
17
    ModelVO getModle(){
18
       Model model = new Model();
19
       model.setId("123456");
20
       model.setName("张三");
21
       model.setCreate(new Date());
22
       return modelMapper.conver(model);
23
    }
24
}