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๊ฐœ๋ฐœ์ƒํ™œ/Java11

๋กฌ๋ณต ๋นŒ๋” ๊ธฐ๋ณธ๊ฐ’ ๋ชจ๋ธ์— ๊ธฐ๋ณธ๊ฐ’์„ ์ฃผ๊ณ  ์‹ถ์„ ๋•Œ, ๋นŒ๋”์—์„œ ๋”ฐ๋กœ ์ง€์ • ์•ˆํ•ด๋„ ํ•ด๋‹น ์–ด๋…ธํ…Œ์ด์…˜ ๊ธฐ๋ฐ˜์œผ๋กœ ๊ธฐ๋ณธ๊ฐ’ ์„ธํŒ… 2024. 6. 11.
์‹คํ–‰ ์ง€์—ฐ TimeUnit.Sleep ๋”œ๋ ˆ์ด๋ฅผ ์ค„ ๋•Œ, Thread.Sleep ๋ณด๋‹ค๋Š” TimeUnit.Sleep๋ฅผ ์“ฐ์ž. ์ฝ”๋“œ๋ฅผ ๋ณด๋ฉด ๊ฒฐ๊ตญ TimeUnit.Sleep์—์„œ Thread.sleep๋ฅผ ์ฝœํ•œ๋‹ค. ๊ธฐ๊ฐ€ ๊ธฐ์ง€๋งŒ TimeUnit.Sleep๋ฅผ ์“ฐ๋Š” ์ด์œ ๋Š” 1. ๊ฐ€๋…์„ฑ์ด ๋” ์ข‹๋‹ค ๋งŒ์•ฝ์— 3๋ถ„ Delay๋ฅผ ์ค€๋‹ค Thread.Sleep(3 * 60 * 1000); == Thread.sleep(180000); //์œผํœด ํ•œ๋ฒˆ์— ๋ชป ์•Œ์•„ ๋จน์–ด = TimeUnit.MINUTES.Sleep(3); 2. 1์˜ ์—ฐ์žฅ์„ ์œผ๋กœ ์‹œ๊ฐ„ ๋‹จ์œ„ ์„ ํƒ์ด ๊ฐ€๋Šฅํ•˜๋‹ค. TimeUnit: DAYS, HOURS, MICROSECONDS, MILLISECONDS, MINUTES, NANOSECONDS.SECONDS 3. ์•ˆ์ •์„ฑ ์‹œ๊ฐ„ ์ดˆ๊ณผ๊ฐ€ ์–‘์ˆ˜์ธ์ง€ ํ™•์ธํ•œ ํ›„ ํ˜ธ์ถœํ•จ. (ํƒ€์ž„ ์•„์›ƒ์ด.. 2023. 5. 31.
char to int ์•„์Šคํ‚ค์ฝ”๋“œ๋ฅผ ์•Œ์•„์•ผํ•จ 1. '1' - 48; (์•„์Šคํ‚ค์ฝ”๋“œ 48์€ 0์ด๋‹ค) 2. '1' - '0' 3. Character.getNumericValue('1'); 2023. 5. 10.
ObjectMapper ์‚ฌ์šฉ List Mapping ObjectMapper ์‚ฌ์šฉํ•ด์„œ List๋ฅผ ํ•œ๋ฐฉ์— ํŠน์ • ํƒ€์ž…์˜ List๋กœ ๋งคํ•‘ ์‹œํ‚ฌ ๋•Œ list list mapping import com.fasterxml.jackson.core.type.TypeReference; import com.fasterxml.jackson.databind.DeserializationFeature; import com.fasterxml.jackson.databind.ObjectMapper; ... ObjectMapper mapper = new ObjectMapper(); mapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false); //์—ฌ๊ธฐ ์„ ์–ธ ์•Š๊ณ  Model ์ชฝ์— lombok annotation ์‚ฌ์šฉํ•ด.. 2022. 11. 28.
[Java] List ๋‚˜๋ˆ„๊ธฐ As-Is ํž˜๋“ค๊ฒŒ ๋‚˜๋ˆ„๋Š” ๋ฒ• (subList) public static void main(String[] args) { List integerList = new ArrayList(); for(int i = 0; i 2022. 5. 23.
[Java] Null String Casting Null์„ String์œผ๋กœ Castingํ•  ๋•Œ, Null Pointer Exception ์•ˆ๋ฐœ์ƒํ•จ. ์ž˜ ์บ์ŠคํŒ…๋จ 2022. 4. 29.
[Java] Map ์ œ๊ณต ๋ฉ”์„œ๋“œ๋“ค ์ •๋ฆฌ map.getOrDefault(key,0) null ์ธ ๊ฒฝ์šฐ Default ๊ฐ’ 0์œผ๋กœ ์ง€์ • map.containsKey('A') ํ‚ค ๊ฐ’์— ํ•ด๋‹น ๊ฐ’(A)๊ฐ€ ํฌํ•จ๋˜์–ด ์žˆ๋Š”์ง€ ์ฒดํฌ map.size() ๋งต ํฌ๊ธฐ ์ฒดํฌ map.isEmpty() ๋งต์ด ๋น„์–ด์žˆ๋Š”์ง€ ์ฒดํฌ map.remove('A') ๋งต์—์„œ ํ‚ค๊ฐ€ A์ธ ํ•ญ๋ชฉ ์‚ญ์ œ A๋ผ๋Š” ํ‚ค์˜ value๊ฐ’ ๋ฆฌํ„ด 2022. 4. 26.
[JAVA] String ์ค‘๋ณต์ œ๊ฑฐ Stream String str = "asdgaassdf"; - ๋ฌธ์ž์—ด์„ Character[]์œผ๋กœ ๋ณ€ํ™˜ํ•ด์ค˜์•ผํ•จ char[] -> Chcaracter[]๋ณด๋‹ค string -> Character[]์ด ๋” ๊ฐ„๋‹จํ•œ๊ฑฐ ๊ฐ™์€ ์ด์œ ๋Š” ๋ญ˜๊นŒ Character[] charObjectArray = str.chars().mapToObj(c -> (char)c).toArray(Character[]::new); - ์ค‘๋ณต ์ œ๊ฑฐ Stream characterStream = Arrays.stream(charObjectArray).distinct(); - String์œผ๋กœ ๋ฆฌํ„ด String result2 = characterStream.map(String::valueOf).collect(Collectors.joining()); - ํ•œ๋ฐฉ์— ํ•ฉ์น˜๋ฉด? .. 2022. 3. 22.
[JAVA] Case Format ๋ณ€๊ฒฝ (UPPER_CAMEL, LOWER_HYPEN...) google guava ์‚ฌ์šฉ google CaseFormat import import com.google.common.base.CaseFormat; ์›ํ•˜๋Š” ํฌ๋งท์œผ๋กœ ๋ณ€๊ฒฝ String upperCamelVndr = CaseFormat.LOWER_HYPHEN.to(CaseFormat.UPPER_CAMEL, "text_test"); //TextTest ํฌ๋งท ์ข…๋ฅ˜ //CaseFormat enum ๊ฐ€๋ณด๋ฉด ์ž์„ธํ•˜๊ฒŒ ํ™•์ธ ๊ฐ€๋Šฅ LOWER_HYPHEN(CharMatcher.is('-'), "-") { String normalizeWord(String word) { return Ascii.toLowerCase(word); } String convert(CaseFormat format, String s) { if (for.. 2022. 3. 22.

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