{"id":6967,"date":"2022-11-10T13:50:07","date_gmt":"2022-11-10T04:50:07","guid":{"rendered":"https:\/\/www.skyer9.pe.kr\/wordpress\/?p=6967"},"modified":"2022-11-10T14:17:48","modified_gmt":"2022-11-10T05:17:48","slug":"java-stream-2","status":"publish","type":"post","link":"https:\/\/www.skyer9.pe.kr\/wordpress\/?p=6967","title":{"rendered":"Java – Stream"},"content":{"rendered":"

Java – Stream<\/h1>\n

Java Stream\uc758 filter(), map(), flatMap() \uc0ac\uc6a9 \ubc29\ubc95\uc744 \uc815\ub9ac\ud569\ub2c8\ub2e4.<\/p>\n

\ub370\uc774\ud0c0 \uc900\ube44<\/h2>\n
Map<String, String> map = new HashMap<>();\nmap.put("key01", "value01");\nmap.put("key02", "value02");\nmap.put("key03", "value03");\nmap.put("key04", "value04");\nmap.put("key05", "value05");<\/code><\/pre>\n
filter()<\/h2>\n
\uc870\uac74\uc5d0 \ubd80\ud569\ud558\ub294 \ub370\uc774\ud0c0\ub97c \ucd94\ucd9c\ud569\ub2c8\ub2e4.<\/p>\n
Optional<Map.Entry<String, String>> entry = map\n        .entrySet()\n        .stream()\n        .filter(e -> e.getKey().equals("key02"))\n        .findFirst();\n\nentry.ifPresent(stringStringEntry ->\n        System.out.println("[key]:" + stringStringEntry.getKey() + ", [value]:" + stringStringEntry.getValue())\n);<\/code><\/pre>\n
map()<\/h2>\n
\uac01 \ub370\uc774\ud0c0\uc5d0 \ud568\uc218\ub97c \uc801\uc6a9\ud569\ub2c8\ub2e4.<\/p>\n
Optional<String> entry = map\n        .entrySet()\n        .stream()\n        .filter(e -> e.getKey().startsWith("key"))\n        .map(e -> e.getValue())\n        .findFirst();\n\nentry.ifPresent(value ->\n        System.out.println("[value]:" + value)\n);<\/code><\/pre>\n
flatMap()<\/h2>\n
2\ucc28\uc6d0 \ubc30\uc5f4\uc744 1\ucc28\uc6d0 \ubc30\uc5f4\ub85c \ubcc0\ud658\ud574 \uc90d\ub2c8\ub2e4.<\/p>\n
String[][] arrays = new String[][]{ {"a1", "a2"}, {"b1", "b2"}, {"c1", "c2", "c3"} };\n\nArrays\n        .stream(arrays)\n        .flatMap(Arrays::stream)\n        .filter(s-> s.startsWith("a"))\n        .map(String::toUpperCase).forEach(System.out::println);<\/code><\/pre>\n","protected":false},"excerpt":{"rendered":"
Java – Stream Java Stream\uc758 filter(), map(), flatMap() \uc0ac\uc6a9 \ubc29\ubc95\uc744 \uc815\ub9ac\ud569\ub2c8\ub2e4. \ub370\uc774\ud0c0 \uc900\ube44 Map<String, String> map = new HashMap<>(); map.put("key01", "value01"); map.put("key02", "value02"); map.put("key03", "value03"); map.put("key04", "value04"); map.put("key05", "value05"); filter() \uc870\uac74\uc5d0 \ubd80\ud569\ud558\ub294 \ub370\uc774\ud0c0\ub97c \ucd94\ucd9c\ud569\ub2c8\ub2e4. Optional<Map.Entry<String, String>> entry = map .entrySet() .stream() .filter(e -> e.getKey().equals("key02")) .findFirst(); entry.ifPresent(stringStringEntry -> System.out.println("[key]:" + stringStringEntry.getKey() + ", [value]:" + stringStringEntry.getValue())\u2026 Read More »<\/a><\/span><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[8],"tags":[],"class_list":["post-6967","post","type-post","status-publish","format-standard","hentry","category-java"],"_links":{"self":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/6967","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=6967"}],"version-history":[{"count":2,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/6967\/revisions"}],"predecessor-version":[{"id":6970,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=\/wp\/v2\/posts\/6967\/revisions\/6970"}],"wp:attachment":[{"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=6967"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=6967"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.skyer9.pe.kr\/wordpress\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=6967"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}