MapStruct - 列舉對映

Mapstruct 自動對映列舉。具有相同名稱的列舉會被自動對映。對於不同的名稱，我們可以使用 `@ValueMapping` 註解來執行對映。

語法

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

以下示例演示了相同的內容。

示例

在 Eclipse 中，按 對映流 章節中更新的內容開啟專案對映。

使用以下程式碼建立 OrderType.java −

OrderType.java

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

使用以下程式碼建立 PlacedOrderType.java −

PlacedOrderType.java

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

使用以下程式碼更新 UtilityMapper.java −

UtilityMapper.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);
}

使用以下程式碼更新 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());
   }
}

執行以下命令以測試對映。

mvn clean test

輸出

一旦命令成功。驗證輸出。

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
...