ModelMapper 高级使用
ModelMapper 是一个 Object To Object 的工具，类似于 MapStruct又不同于 MapStruct。主要原因是 ModelMapper 是利用反射的原理实现的 Object To Object。
ModelMapper 官方API ： http://modelmapper.org/user-manual/property-mapping/
使用实例
本实例实现了条件映射、嵌套映射（对象中有对象映射）、自定义属性映射、List 集合映射（对象中有集合映射）、Map集合映射（对象中有集合映射）、忽略映射，默认值设置（ModelMapper 的默认值设置时一不小心就会入坑，如果直接设置默认值，当再赋值转换时，默认值会覆盖赋值的值，所以设置默认值需要结合条件映射）等。
验证了对象属性为集合，集合中还有集合能够使用 ModelMapper 进行转换。不足点是这个实例中没有验证有继承关系时的映射（使用 modelMapper.includeBase(父类1, 父类2) 方法），多个属性映射为一个属性或一个属性映射为多个属性（使用 PropertyMap 转换器）。
- 使用条件映射设置默认值。当 age/createTime 没有值时设置默认值为18/当前时间，有值时不设置默认值；
- 嵌套映射，自定义属性映射。Source 的 sourceSon 成员变量 映射到 Destination 的 destinationSon 成员变量；
- List集合映射。Source 的 listSon 成员变量 映射到 Destination 的 sonList 成员变量；
- Map集合映射。Source 的 mapSon 成员变量 映射到 Destination 的 sonMap 成员变量；
- 忽略映射。忽略 Destination 的 excessParam 成员变量，如果不忽略将验证不过，报 org.modelmapper.MappingException: ModelMapper mapping errors；
实体类
（1）BaseClass
@Getter
@Setter
public class BaseClass {
private String id;
private String name;
public BaseClass() {
}
public BaseClass(String id, String name) {
this.id = id;
this.name = name;
}
}（2）SouSubClass
@Getter
@Setter
public class SouSubClass {
private String sonId;
private String sonName;
private List<BaseClass> grandSons;
public SouSubClass() {
}
public SouSubClass(String sonId, String sonName) {
this.sonId = sonId;
this.sonName = sonName;
}
}（3）DestSubClass
@Getter
@Setter
public class DestSubClass {
private String dsonId;
private String sonName;
private String excessParam;
private List<BaseClass> grandSons;
public DestSubClass(){
}
public DestSubClass(String dsonId, String sonName) {
this.dsonId = dsonId;
this.sonName = sonName;
}
}（4）Source
@Getter
@Setter
public class Source {
private String id;
private String name;
private Integer age;
private SouSubClass sourceSon;
private List<SouSubClass> listSon;
private Map<Integer, SouSubClass> mapSon;
private Date createTime;
public Source() {
}
public Source(String id, String name) {
this.id = id;
this.name = name;
}
public Source(String id, String name, Integer age) {
this.id = id;
this.name = name;
this.age = age;
}
}（5）Destination
@Getter
@Setter
public class Destination {
private Long id;
private String name;
private Integer age;
private DestSubClass destinationSon;
private List<DestSubClass> sonList;
private Map<Integer, DestSubClass> sonMap;
private String excessParam;
private Date createTime;
public Destination() {
}
public Destination(Long id, String name) {
this.id = id;
this.name = name;
}
}ModelMapper 配置类
@Configuration
public class ModelMapperConfig {
@Bean
@Scope("singleton")
public ModelMapper getModelMapper() {
ModelMapper modelMapper = new ModelMapper();
//默认为standard模式，设置为strict模式
modelMapper.getConfiguration().setMatchingStrategy(MatchingStrategies.STRICT);
// 类型映射代码
sourceSonToDestinationSon(modelMapper);
sourceToDestination(modelMapper);
//验证映射
modelMapper.validate();
// 配置代码
return modelMapper;
}
private void sourceSonToDestinationSon(ModelMapper modelMapper) {
modelMapper.createTypeMap(SouSubClass.class, DestSubClass.class)
.addMapping(SouSubClass::getSonId, DestSubClass::setDsonId)
.addMapping(SouSubClass::getSonName, DestSubClass::setSonName)
.addMappings(mapper -> mapper.skip(DestSubClass::setExcessParam));
}
private void sourceToDestination(ModelMapper modelMapper) {
modelMapper.createTypeMap(Source.class, Destination.class)
.addMappings(mapper -> mapper.using((Converter<Integer, Integer>) context -> {
if (context.getSource() == null) {
return 18;
}
return context.getSource();
}).map(Source::getAge, Destination::setAge))
.addMappings(mapper -> mapper.using((Converter<Date, Date>) context -> {
if (context.getSource() == null) {
return new Date();
}
return context.getSource();
}).map(Source::getCreateTime, Destination::setCreateTime))
.addMapping(Source::getSourceSon, Destination::setDestinationSon)
.addMapping(Source::getListSon, Destination::setSonList)
.addMapping(Source::getMapSon, Destination::setSonMap)
.addMappings(mapper -> mapper.skip(Destination::setExcessParam));
}
}ModelMapper Service 类
public interface TestService {
Destination testSourceToDestination(Source source);
List<Destination> testSourceToDestinationList(List<Source> sources);
}@Service
public class TestServiceImpl implements TestService {
@Autowired
private ModelMapper modelMapper;
@Override
public Destination testSourceToDestination(Source source) {
Destination destination = modelMapper.map(source, Destination.class);
return destination; // a 处
}
@Override
public List<Destination> testSourceToDestinationList(List<Source> sources) {
Type type = new TypeToken<List<Destination>>(){}.getType();
List<Destination> destinations = modelMapper.map(sources, type);
return destinations; // b 处
}
}测试类
@RunWith(SpringRunner.class)
@SpringBootTest(classes = TestApplication.class)
public class TestServiceImplTest {
@Autowired
private TestService testService;
private static Source source1 = new Source("a", "发生的", 24);
private static Source source2 = new Source("b", "发生的");
private static List<Source> sources = new ArrayList<>();
static {
List<BaseClass> baseClasses1 = new ArrayList<>();
baseClasses1.add(new BaseClass("aa", "发生的111"));
baseClasses1.add(new BaseClass("bb", "发生的222"));
SouSubClass subClass1 = new SouSubClass("aaa", "发生的3333");
subClass1.setGrandSons(baseClasses1);
List<BaseClass> baseClasses2 = new ArrayList<>();
baseClasses2.add(new BaseClass("cc", "国防观"));
baseClasses2.add(new BaseClass("dd", "国防观"));
SouSubClass subClass2 = new SouSubClass("ccc", "规范的大哥");
subClass2.setGrandSons(baseClasses2);
List<SouSubClass> sourceSonList = new ArrayList<>();
sourceSonList.add(subClass1);
sourceSonList.add(subClass2);
Map<Integer, SouSubClass> sourceSonMap = new HashMap<>();
sourceSonMap.put(1, subClass1);
sourceSonMap.put(2, subClass2);
source1.setCreateTime(new Date(System.currentTimeMillis()-98978609));
source1.setSourceSon(subClass1);
source1.setListSon(sourceSonList);
source1.setMapSon(sourceSonMap);
source2.setSourceSon(subClass1);
source2.setListSon(sourceSonList);
source2.setMapSon(sourceSonMap);
sources.add(source1);
sources.add(source2);
}
@Test
public void testSourceToDestination() {
testService.testSourceToDestination(source1);
testService.testSourceToDestination(source2);
}
@Test
public void testSourceToDestinationList() {
testService.testSourceToDestinationList(sources);
}
}测试结果
在 ab 两处打上断点，查看变量转换前后的值，证实转换成功。
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