MapStruct 映射流

使用 Mapstruct 我们可以像创建集合一样创建流映射。

语法

@Mapper
public interface UtilityMapper {
Stream<String> getStream(Stream<Integer> source);
}

示例

打开映射 Map 章节中更新的项目映射。

使用以下代码更新 UtilityMapper.java

UtilityMapper.java

package com.jiyik.mapper;

import org.mapstruct.MapMapping;
import org.mapstruct.Mapper;

import java.util.GregorianCalendar;
import java.util.Map;
import java.util.stream.Stream;

@Mapper
public interface UtilityMapper {
    @MapMapping(valueDateFormat = "dd.MM.yyyy")
    Map<String, String> getMap(Map<Long, GregorianCalendar> source);
    Stream<String> getStream(Stream<Integer> source);
}

使用以下代码更新 UtilityMapperTest.java

UtilityMapperTest.java

import com.jiyik.mapper.UtilityMapper;
import org.junit.Test;
import org.mapstruct.factory.Mappers;

import java.util.Arrays;
import java.util.GregorianCalendar;
import java.util.HashMap;
import java.util.Map;
import java.util.stream.Stream;

import static org.junit.Assert.assertEquals;

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());
    }
}

运行以下命令来测试映射。

$ mvn clean test

执行结果如下