Mapstruct 简明教程
MapStruct - Using Custom Mapper
Mapstruct 映射器允许创建自定义映射器方法来映射对象。我们可以向映射器接口添加一个默认方法。
Syntax
@Mapper(uses=DateMapper.class)
public interface UtilityMapper {
default Car getCar(CarEntity entity) {
Car car = new Car();
car.setId(entity.getId());
car.setName(entity.getName());
return car;
}
}
以下示例演示了相同内容。
Example
在 Eclipse 中打开更新的 Mapping Enum 章节中的项目映射。
使用以下代码更新 UtilityMapper.java −
UtilityMapper.java
package com.tutorialspoint.mapper;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
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.entity.CarEntity;
import com.tutorialspoint.enums.OrderType;
import com.tutorialspoint.enums.PlacedOrderType;
import com.tutorialspoint.model.Car;
@Mapper(uses=DateMapper.class)
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);
CarEntity getCarEntity(Car car) throws ParseException;
default Car getCar(CarEntity entity) {
Car car = new Car();
car.setId(entity.getId());
car.setName(entity.getName());
return car;
}
}
class DateMapper {
public String asString(GregorianCalendar date) {
return date != null ? new SimpleDateFormat( "yyyy-MM-dd" )
.format( date.getTime() ) : null;
}
public GregorianCalendar asDate(String date) throws ParseException {
Date date1 = date != null ? new SimpleDateFormat( "yyyy-MM-dd" )
.parse( date ) : null;
if(date1 != null) {
return new GregorianCalendar(date1.getYear(), date1.getMonth(),date1.getDay());
}
return null;
}
}
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 static org.junit.jupiter.api.Assertions.assertTrue;
import java.text.ParseException;
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.entity.CarEntity;
import com.tutorialspoint.enums.OrderType;
import com.tutorialspoint.enums.PlacedOrderType;
import com.tutorialspoint.mapper.UtilityMapper;
import com.tutorialspoint.model.Car;
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("2015-04-05", 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());
}
@Test
public void testGetCarEntity() {
Car car = new Car();
car.setId(1);
car.setManufacturingDate("11/10/2020");
boolean exceptionOccured = false;
try {
CarEntity carEntity = utilityMapper.getCarEntity(car);
} catch (ParseException e) {
exceptionOccured = true;
}
assertTrue(exceptionOccured);
}
@Test
public void testGetCar() {
CarEntity entity = new CarEntity();
entity.setId(1);
entity.setName("ZEN");
Car car = utilityMapper.getCar(entity);
assertEquals(entity.getId(), car.getId());
assertEquals(entity.getName(), car.getName());
}
}
运行以下命令以测试映射。
mvn clean test
Output
命令成功后。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: 5, Failures: 0, Errors: 0, Skipped: 0, Time elapsed: 0 sec
Results :
Tests run: 9, Failures: 0, Errors: 0, Skipped: 0
...