MapStruct - 映射枚举

---

Mapstruct 自动映射枚举。具有相同名称的枚举会自动映射。如果名称不同，我们可以使用@ValueMapping注解进行映射。

句法

@Mapper
public interface UtilityMapper {
   @ValueMapping(source = "EXTRA", target = "SPECIAL")
   PlacedOrderType getEnum(OrderType order);
}

以下示例演示了相同的内容。

例子

打开项目映射，如Eclipse 中的“映射流”章节中更新的那样。

使用以下代码创建 OrderType.java -

订单类型.java

package com.tutorialspoint.enums;
public enum OrderType {
   EXTRA, NORMAL, STANDARD
}

使用以下代码创建 PlacedOrderType.java -

PlacedOrderType.java

package com.tutorialspoint.enums;
public enum PlacedOrderType {
   SPECIAL, NORMAL, STANDARD
}

使用以下代码更新 UtilityMapper.java -

实用程序映射器.java

package com.tutorialspoint.mapper;

import java.util.GregorianCalendar;
import java.util.Map;
import java.util.stream.Stream;
import org.mapstruct.MapMapping;
import org.mapstruct.Mapper;
import org.mapstruct.ValueMapping;
import com.tutorialspoint.enums.OrderType;
import com.tutorialspoint.enums.PlacedOrderType;

@Mapper
public interface UtilityMapper {
   @MapMapping(valueDateFormat = "dd.MM.yyyy")
   Map<String, String> getMap(Map<Long, GregorianCalendar> source);
   Stream<String> getStream(Stream<Integer> source);
   
   @ValueMapping(source = "EXTRA", target = "SPECIAL")
   PlacedOrderType getEnum(OrderType order);
}

使用以下代码更新 UtilityMapperTest.java -

UtilityMapperTest.java

package com.tutorialspoint.mapping;

import static org.junit.jupiter.api.Assertions.assertEquals;
import java.util.Arrays;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Stream;
import org.junit.jupiter.api.Test;
import org.mapstruct.factory.Mappers;
import com.tutorialspoint.enums.OrderType;
import com.tutorialspoint.enums.PlacedOrderType;
import com.tutorialspoint.mapper.UtilityMapper;

public class UtilityMapperTest {
   private UtilityMapper utilityMapper=Mappers.getMapper(UtilityMapper.class);

   @Test
   public void testMapMapping() {
      Map<Long, GregorianCalendar> source = new HashMap<>();
      source.put(1L, new GregorianCalendar(2015, 3, 5));

      Map<String, String> target = utilityMapper.getMap(source);
      assertEquals("05.04.2015", target.get("1"));		
   }
   @Test
   public void testGetStream() {
      Stream<Integer> numbers = Arrays.asList(1, 2, 3, 4).stream();
      Stream<String> strings = utilityMapper.getStream(numbers);
      assertEquals(4, strings.count());			
   }   
   @Test
   public void testGetEnum() {
      PlacedOrderType placedOrderType = utilityMapper.getEnum(OrderType.EXTRA);
      PlacedOrderType placedOrderType1 = utilityMapper.getEnum(OrderType.NORMAL);
      PlacedOrderType placedOrderType2 = utilityMapper.getEnum(OrderType.STANDARD);
      assertEquals(PlacedOrderType.SPECIAL.name(), placedOrderType.name());
      assertEquals(PlacedOrderType.NORMAL.name(), placedOrderType1.name());
      assertEquals(PlacedOrderType.STANDARD.name(), placedOrderType2.name());
   }
}

运行以下命令来测试映射。

mvn clean test

输出

一旦命令成功。验证输出。

mvn clean test
[INFO] Scanning for projects...
...
[INFO] --- maven-surefire-plugin:2.12.4:test (default-test) @ mapping ---
[INFO] Surefire report directory: \mvn\mapping\target\surefire-reports

-------------------------------------------------------
 T E S T S
-------------------------------------------------------
Running com.tutorialspoint.mapping.CarMapperTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.256 sec
Running com.tutorialspoint.mapping.DeliveryAddressMapperTest
Tests run: 1, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0.001 sec
Running com.tutorialspoint.mapping.StudentMapperTest
Tests run: 2, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec
Running com.tutorialspoint.mapping.UtilityMapperTest
Tests run: 3, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec

Results :

Tests run: 7, Failures: 0, Errors: 0, Skipped: 0
...