JAVA/Stream

 

Map List 검색

List<Map<String, String>> payCompleteList = new ArrayList<>();
payCompleteList.add(new HashMap<String, String>() {{ put("RECEIPT_YM", "202207"); put("aaa", "aa1"); } });
payCompleteList.add(new HashMap<String, String>() {{ put("RECEIPT_YM", "202210"); put("aaa", "aa2"); } });

Set<String> receiptYearMonthSets = new HashSet<String>();
payCompleteList.forEach(e -> receiptYearMonthSets.add(e.get("RECEIPT_YM")));

System.out.println(receiptYearMonthSets.contains("202207"));
System.out.println(receiptYearMonthSets.contains("202209"));

 

검색 및 변경

List<Map<String, String>> payCompleteList = new ArrayList<>();
payCompleteList.add(new HashMap<String, String>() {{ put("RECEIPT_YM", "202207"); put("aaa", "aa1"); } });
payCompleteList.add(new HashMap<String, String>() {{ put("RECEIPT_YM", "202210"); put("aaa", "aa2"); } });

Set<String> receiptYearMonthSets = new HashSet<String>();
payCompleteList.forEach(e -> receiptYearMonthSets.add(e.get("RECEIPT_YM")));

List<Map<String, String>> monthList = new ArrayList<>();
monthList.add(new HashMap<String, String>() {{ put("RECEIPT_YM", "202207"); put("RECEIPT_DATE", "20220705"); } });
monthList.add(new HashMap<String, String>() {{ put("RECEIPT_YM", "202208"); put("RECEIPT_DATE", "20220805"); } });
monthList.add(new HashMap<String, String>() {{ put("RECEIPT_YM", "202209"); put("RECEIPT_DATE", "20220905"); } });

List<Map<String, String>> searchResult =
    monthList.stream()
        .filter(map -> map.entrySet().stream().anyMatch(e -> e.getValue().equals("20220705")))
        .collect(Collectors.toList());

System.out.println(searchResult);

if (receiptYearMonthSets.size() > 0) {
    for (Map<String, String> map : monthList) {
        if (receiptYearMonthSets.contains(map.get("RECEIPT_YM")) == true) {
            map.put("aaa", "aaaaa");
        }
    }
}

System.out.println(monthList);

 

내림, 오름차순, 찾기

List<Map<String, String>> list = new ArrayList<>();
list.add(new HashMap<String, String>() {{ put("HOUSE_ID", "6417"); put("HOUSE_NAME", "다비 쉐어하우스");  } });
list.add(new HashMap<String, String>() {{ put("HOUSE_ID", "7955"); put("HOUSE_NAME", "덕준 광명 지점-t1"); } });

System.out.println(list);
System.out.println("========");


// 내림차순
List<Map<String, String>> sortingDescResult = list.stream()
    .sorted((o1, o2) -> o1.get("HOUSE_ID").toString().compareTo(o2.get("HOUSE_ID").toString()) )
    .collect(Collectors.toList());

// 오름차순
List<Map<String, String>> sortingAscResult = list.stream()
    .sorted((o1, o2) -> o2.get("HOUSE_ID").toString().compareTo(o1.get("HOUSE_ID").toString()) )
    .collect(Collectors.toList());

// 찾기
Map<String, String> searchResult = list.stream()
    .filter(x -> x.get("HOUSE_ID").equals("7955")).findAny()
    .get();

 

피벗

List<Map<String, String>> list = new ArrayList<>();
list.add(new HashMap<String, String>() {{ put("HOUSE_ID", "6417"); put("HOUSE_NAME", "다비 쉐어하우스");  } });
list.add(new HashMap<String, String>() {{ put("HOUSE_ID", "7955"); put("HOUSE_NAME", "덕준 광명 지점-t1"); } });


Map<String, String> pivot = list.stream()
    .collect(Collectors.toMap(
        i1 -> i1.get("HOUSE_ID"),
        i2 -> i2.get("HOUSE_NAME")
    ));

System.out.println(pivot);