[Java 7편] stream list to map<String, Dto>

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[Java 7편] stream list to map<String, Dto>

Stream List to Map<String, DTO>

• list 를 Map<String, DTO> 변환하는 예제를 정리했습니다.

Source

	public class StreamListToMapObjectTest {
	@Test
	@DisplayName("list를Map<String, DTO> 변환")
	public void streamListToMapObjectTest01() throws Exception {
	List<DtoA> list = new ArrayList<>();
	list.add(new DtoA("key1", "bcde"));
	list.add(new DtoA("key2", "bcde123"));
	Map<String, DtoB> map =
	list.stream().map(a -> new DtoB(a.getKey(), a.getValue()))
	.collect(Collectors.toMap(DtoB::getKey, Function.identity()));
	Assertions.assertEquals(2, map.keySet().size());
	Assertions.assertEquals("bcde", map.get("key1").getValue());
	Assertions.assertEquals("key1", map.get("key1").getKey());
	}
	private static class DtoA {
	private String key;
	private String value;
	public DtoA(String key, String value) {
	this.key = key;
	this.value = value;
	}
	public String getKey() {
	return key;
	}
	public String getValue() {
	return value;
	}
	}
	private static class DtoB {
	private String key;
	private String value;
	public DtoB(String key, String value) {
	this.key = key;
	this.value = value;
	}
	public String getKey() {
	return key;
	}
	public String getValue() {
	return value;
	}
	}
	}

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