{"id":2441,"date":"2016-09-21T15:42:25","date_gmt":"2016-09-21T15:42:25","guid":{"rendered":"http:\/\/www.gisdeveloper.co.kr\/?p=2441"},"modified":"2016-09-21T15:42:25","modified_gmt":"2016-09-21T15:42:25","slug":"java-java8-streams","status":"publish","type":"post","link":"http:\/\/www.gisdeveloper.co.kr\/?p=2441","title":{"rendered":"[Java] Java8, \uc2a4\ud2b8\ub9bc(Streams)"},"content":{"rendered":"

A java.util.Stream \ud074\ub798\uc2a4\ub294 \ub3d9\uc77c\ud55c \ud0c0\uc785\uc758, \ub2e4\uc218\uc758 \ub370\uc774\ud130\uc5d0 \ub300\ud574 \ub2e4\uc591\ud55c \uc5f0\uc0b0\uc744 \ube60\ub974\uac8c \uc801\uc6a9\ud560 \uc218 \uc788\ub294 \uae30\ub2a5\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc2a4\ud2b8\ub9bc\uc740 java.util.Collection \uac1d\uccb4\ub85c\ubd80\ud130 \uc0dd\uc131\ub418\ub294\ub370, \ub9ac\uc2a4\ud2b8\ub098 \uc9d1\ud569 \ub4f1\uc774 \uadf8 \uc608\uc778\ub370\uc694. \ub9f5\uc740 \uc9c0\uc6d0\ud558\uc9c0 \uc54a\uc2b5\ub2c8\ub2e4. \ub2e4\uc74c\uacfc \uac19\uc740 \ub9ac\uc2a4\ud2b8\uac00 \uc788\ub2e4\uace0 \ud558\uace0 \uc774 \ub9ac\uc2a4\ud2b8\ub97c \ud1b5\ud574 \uc2a4\ud2b8\ub9bc\uc744 \ub9cc\ub4e4\uc5b4 \ub2e4\uc591\ud55c, \uc720\uc6a9\ud55c \uc5f0\uc0b0\uc758 \uc608\uc81c \ucf54\ub4dc\ub97c \uc5b8\uae09\ud558\uaca0\uc2b5\ub2c8\ub2e4.<\/P><\/p>\n

\nList stringCollection = new ArrayList<>();\n\t\t\nstringCollection.add(\"\uc2e0\uc219\uc8fc\");\nstringCollection.add(\"\uae40\uc625\uc790\");\nstringCollection.add(\"\uc870\ubbf8\ud604\");\t\t\nstringCollection.add(\"\uc1a1\uae30\uc219\");\nstringCollection.add(\"\ucd5c\ubbf8\ub77c\");\nstringCollection.add(\"\ubc15\ubbf8\ub0a8\");\nstringCollection.add(\"\uae40\uad6c\ub77c\");\nstringCollection.add(\"\uae40\ud615\uc900\");\n<\/pre>\n
filter<\/h3>\n
\uc694\uc18c \uc911 ‘\uae40’\uc73c\ub85c \uc2dc\uc791\ud558\ub294 \ubb38\uc790\uc5f4\uc744 \uac78\ub7ec\ub0b4\uc5b4 \ud654\uba74\uc5d0 \ud45c\uc2dc\ud569\ub2c8\ub2e4.<\/p>\n
\nstringCollection\n    .stream()\n    .filter((s) -> s.startsWith(\"\uae40\"))\n    .forEach(System.out::println);\n<\/pre>\n
sorted<\/h3>\n
\uc694\uc18c\ub97c \uc815\ub82c\ud558\uace0, \uc815\ub82c\ub41c \ub9ac\uc2a4\ud2b8\uc5d0 \ub300\ud574 ‘\uae40’\uc790\ub85c \uc2dc\uc791\ud558\ub294 \uc694\uc18c\ub97c \ud654\uba74\uc5d0 \ud45c\uc2dc\ud569\ub2c8\ub2e4.<\/p>\n
\nstringCollection\n    .stream()\n    .sorted()\n    .filter((s) -> s.startsWith(\"\uae40\"))\n    .forEach(System.out::println);\n<\/pre>\n
map<\/h3>\n
\uc694\uc18c \uac01\uac01\uc5d0 \ud568\uc218\ub97c \ud638\ucd9c\ud569\ub2c8\ub2e4. \uc544\ub798\ub294 \uac01 \uc694\uc18c\uc758 \ub4a4\uc5d0 ‘\uc528’ \uc790\ub97c \ubd99\uc774\uace0 \uc815\ub82c\ud55c \ud6c4 \ucd9c\ub825\ud569\ub2c8\ub2e4.<\/p>\n
\nstringCollection\n    .stream()\n    .map((a) -> a + \"\uc528\")\n    .sorted((a, b) -> b.compareTo(a))\n    .forEach(System.out::println);\n<\/pre>\n
count<\/h3>\n
‘\uae40’\uc790\ub85c \uc2dc\uc791\ud558\ub294 \uc694\uc18c\uc758 \uac1c\uc218\ub97c \uc5bb\uc2b5\ub2c8\ub2e4.<\/p>\n
\nlong cntKim = stringCollection\n    .stream()\n    .filter((s) -> s.startsWith(\"\uae40\"))\n    .count();\n<\/pre>\n
reduce<\/h3>\n
\uac01 \uc694\uc18c\ub97c \ud558\ub098\ub85c \ubb36\uc2b5\ub2c8\ub2e4.<\/p>\n
\nOptional reduced = stringCollection\n    .stream()\n    .sorted()\n    .reduce((s1, s2) -> s1 + \",\" + s2);\n\nreduced.ifPresent(System.out::println);\n<\/pre>\n
anyMatch, allMatch, noneMatch<\/h3>\n
\uac01 \uc694\uc18c\uc5d0 \ub300\ud574 \uc9c0\uc815\ud55c \uc870\uac74\uc5d0 \ubd80\ud569\ud558\ub294\uc9c0\ub97c \uac80\uc0ac\ud569\ub2c8\ub2e4. \uccab\ubc88\uc9f8\uc778 anyMatch\ub294 ‘\uae40’\uc73c\ub85c \uc2dc\uc791\ud558\ub294 \uc694\uc18c\uac00 \ud558\ub098\ub77c\ub3c4 \uc788\ub2e4\uba74 \ucc38\uc785\ub2c8\ub2e4. \ub450\ubc88\uc9f8\uc778 allMatch\ub294 \ubaa8\ub4e0 \uc694\uc18c\uac00 ‘\uae40’\uc73c\ub85c \uc2dc\uc791\ud574\uc57c\ub9cc \ucc38\uc785\ub2c8\ub2e4. \ub05d\uc73c\ub85c \uc138\ubc88\uc9f8\ub294 ‘\uace0’\ub85c \uc2dc\uc791\ud558\ub294 \uc694\uc18c\uac00 \ud558\ub098\ub3c4 \uc5c6\uc5b4\uc57c ‘\ucc38’\uc785\ub2c8\ub2e4.<\/p>\n
\nboolean anyStartsWithKim = stringCollection\n    .stream()\n    .anyMatch((s) -> s.startsWith(\"\uae40\"));\n\nboolean allStartsWithKim = stringCollection\n    .stream()\n    .allMatch((s) -> s.startsWith(\"\uae40\"));\n\nboolean noneStartsWithGo = stringCollection\n    .stream()\n    .noneMatch((s) -> s.startsWith(\"\uace0\"));\n<\/pre>\n","protected":false},"excerpt":{"rendered":"
A java.util.Stream \ud074\ub798\uc2a4\ub294 \ub3d9\uc77c\ud55c \ud0c0\uc785\uc758, \ub2e4\uc218\uc758 \ub370\uc774\ud130\uc5d0 \ub300\ud574 \ub2e4\uc591\ud55c \uc5f0\uc0b0\uc744 \ube60\ub974\uac8c \uc801\uc6a9\ud560 \uc218 \uc788\ub294 \uae30\ub2a5\uc744 \uc81c\uacf5\ud569\ub2c8\ub2e4. \uc2a4\ud2b8\ub9bc\uc740 java.util.Collection \uac1d\uccb4\ub85c\ubd80\ud130 \uc0dd\uc131\ub418\ub294\ub370, \ub9ac\uc2a4\ud2b8\ub098 \uc9d1\ud569 \ub4f1\uc774 \uadf8 \uc608\uc778\ub370\uc694. \ub9f5\uc740 \uc9c0\uc6d0\ud558\uc9c0 \uc54a\uc2b5\ub2c8\ub2e4. \ub2e4\uc74c\uacfc \uac19\uc740 \ub9ac\uc2a4\ud2b8\uac00 \uc788\ub2e4\uace0 \ud558\uace0 \uc774 \ub9ac\uc2a4\ud2b8\ub97c \ud1b5\ud574 \uc2a4\ud2b8\ub9bc\uc744 \ub9cc\ub4e4\uc5b4 \ub2e4\uc591\ud55c, \uc720\uc6a9\ud55c \uc5f0\uc0b0\uc758 \uc608\uc81c \ucf54\ub4dc\ub97c \uc5b8\uae09\ud558\uaca0\uc2b5\ub2c8\ub2e4. List stringCollection = new ArrayList(); stringCollection.add(“\uc2e0\uc219\uc8fc”); stringCollection.add(“\uae40\uc625\uc790”); stringCollection.add(“\uc870\ubbf8\ud604”); stringCollection.add(“\uc1a1\uae30\uc219”); stringCollection.add(“\ucd5c\ubbf8\ub77c”); stringCollection.add(“\ubc15\ubbf8\ub0a8”); … <\/p>\n
\ub354 \ubcf4\uae30 “[Java] Java8, \uc2a4\ud2b8\ub9bc(Streams)”<\/span><\/a><\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"open","ping_status":"open","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[60],"tags":[],"class_list":["post-2441","post","type-post","status-publish","format-standard","hentry","category-java"],"_links":{"self":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/2441","targetHints":{"allow":["GET"]}}],"collection":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts"}],"about":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcomments&post=2441"}],"version-history":[{"count":0,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=\/wp\/v2\/posts\/2441\/revisions"}],"wp:attachment":[{"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=2441"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=2441"},{"taxonomy":"post_tag","embeddable":true,"href":"http:\/\/www.gisdeveloper.co.kr\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=2441"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}