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2024/03 31

[Error][JAVA] Cannot invoke "String.length()" because "replacement" is null

String originalString = "Hello, world!"; String replacement = null; // This is null String newString = originalString.replace("Hello", replacement); // Trying to replace "Hello" with null ํ•ด๋‹น ์˜ค๋ฅ˜๊ฐ€ ๋ฐœ์ƒํ•  ์ˆ˜ ์žˆ๋Š” ์˜ˆ์ด๋‹ค. ๋‚˜๋Š” replaceAll์„ ์ผ๋Š”๋ฐ replacement ์ž๋ฆฌ์— ๊ฐ’์ด ๋‹ค๋ฅธ ๊ฐ์ฒด์—์„œ ๊ฐ€์ ธ์˜ค๋Š” ๊ฑฐ์˜€๋Š”๋ฐ, ๊ทธ ๊ฐ์ฒด์— ํ•ด๋‹น ๊ฐ’์ด ๋“ค์–ด์žˆ์ง€ ์•Š์•„์„œ ๋ฐœ์ƒํ•œ ์˜ค๋ฅ˜์˜€๋‹ค. ๊ฐ’์„ ์„ธํŒ…ํ•ด์ฃผ๋‹ˆ ์˜ค๋ฅ˜ํ•ด๊ฒฐ.

Error 2024.03.31

[JAVA] ๋ฐฐ์—ด์— ๊ฐ’ ์ถ”๊ฐ€ํ•˜๊ธฐ // js ์—์„œ ๋ฐฐ์—ด์— push()ํ•˜๋Š” ๊ฒƒ๊ณผ ๋น„๊ต

public class Main { public static void main(String[] args) { // 1. ์ง์ ‘ ๋ฌธ์ž์—ด ๋ฐฐ์—ด์„ ์ƒ์„ฑํ•˜์—ฌ ์ดˆ๊ธฐํ™” String[] strings1 = {"Java", "Python", "C++", "JavaScript"}; // 2. ๋ฐฐ์—ด์˜ ํฌ๊ธฐ๋ฅผ ์ง€์ •ํ•˜์—ฌ ์ƒ์„ฑ ํ›„ ๊ฐ ์š”์†Œ์— ๊ฐ’์„ ํ• ๋‹น String[] strings2 = new String[3]; strings2[0] = "Apple"; strings2[1] = "Banana"; strings2[2] = "Orange"; //3. ๋ฐฐ์—ด์˜ ํฌ๊ธฐ๋ฅผ ๋™์ ์œผ๋กœ ์„ค์ •ํ•˜์—ฌ ์ƒ์„ฑ int size = 4; String[] strings3 = new String[size]; strings3[0] = "Cat"; strings3[..

JAVA 2024.03.30

[js][Echarts] x์ถ• ๋ฐ์ดํ„ฐ๊ฐ€ ์ƒ๋žต๋  ๋•Œ / x์ถ• ๋ฐ์ดํ„ฐ ๋Œ€๊ฐ์„ ์œผ๋กœ ํ‘œ์‹œ

x์ถ• ๋ฐ์ดํ„ฐ๊ฐ€ ๊ธธ์ด ๋ฌธ์ œ๋กœ ํ‘œ์‹œ๋˜์ง€ ์•Š๊ณ  ์ƒ๋žต๋˜๋Š” ๊ฒฝ์šฐ๊ฐ€ ์žˆ๋‹ค. ์ „์ฒด x ์ถ• ๋ฐ์ดํ„ฐ๋ฅผ ํ‘œ์‹œํ•˜๊ณ  ์‹ถ๋‹ค๋ฉด, text ๋ฅผ ๋Œ€๊ฐ์„ ์œผ๋กœ ๊ธฐ์šธ์ด๋ฉด ๋œ๋‹ค. ๊ทธ ์„ค์ •์€ ์•„๋ž˜์™€ ๊ฐ™์ด ํ•˜๋ฉด ๋œ๋‹ค. option = { xAxis: { type: 'category', data: ['Mon', 'Tue', 'Wed', 'Thu', 'Fri', 'Sat', 'Sun'], axisLabel: { rotate: 45 // ํ…์ŠคํŠธ ํšŒ์ „ ๊ฐ๋„ (45๋„) } } } axisLabel: { rotate: 45 // ํ…์ŠคํŠธ ํšŒ์ „ ๊ฐ๋„ (45๋„) }

Front/JS & jQuery 2024.03.29

[js][Echarts] Line ์ฐจํŠธ ์ปฌ๋Ÿฌ ์‚ฌ์šฉ์ž ์„ค์ •

series: [ { name: '๊ฑด์ˆ˜', type: 'line', tooltip: { valueFormatter: function (value) { return value; } }, yAxisIndex: 1, data: cnts, lineStyle: { color: 'blue' // Set the desired color for the line } } ] lineStyle: { color: 'blue' // Set the desired color for the line } color ๊ฐ’์— ์ปฌ๋Ÿฌ์ฝ”๋“œ๊ฐ’์„ ๋„ฃ์–ด๋„ ๋œ๋‹ค.

Front/JS & jQuery 2024.03.28

[js][Echarts] bar ์ฐจํŠธ ๋„ˆ๋น„ ์„ค์ •ํ•˜๊ธฐ

series: [ { name: '๊ณ„์•ฝ์˜ˆ์ƒ๊ธˆ์•ก', type: 'bar', barWidth: '50%', // ๋ง‰๋Œ€์˜ ๋„ˆ๋น„๋ฅผ 50%๋กœ ์„ค์ •ํ•˜๋Š” ์˜ˆ์‹œ tooltip: { valueFormatter: function (value) { return value; } }, data: amts } ] barWidth: '50%', // ๋ง‰๋Œ€์˜ ๋„ˆ๋น„๋ฅผ 50%๋กœ ์„ค์ •ํ•˜๋Š” ์˜ˆ์‹œ

Front/JS & jQuery 2024.03.27

[JAVA] ๋นˆ๋ฐฐ์—ด ํ™•์ธ ์‹œ isEmpty() ์™€ size == 0 ์˜ ์ฐจ์ด

Java์—์„œ List๊ฐ€ ๋น„์–ด ์žˆ๋Š”์ง€ ํ™•์ธํ•˜๋ ค๋ฉด ๋‹ค์Œ๊ณผ ๊ฐ™์ด ํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค. isEmpty() ๋ฉ”์„œ๋“œ ์‚ฌ์šฉ: List๊ฐ€ ๋น„์–ด ์žˆ๋Š” ๊ฒฝ์šฐ true๋ฅผ ๋ฐ˜ํ™˜ํ•ฉ๋‹ˆ๋‹ค. size() ๋ฉ”์„œ๋“œ๋ฅผ ์‚ฌ์šฉํ•˜์—ฌ ํฌ๊ธฐ๋ฅผ ํ™•์ธํ•˜๊ฑฐ๋‚˜, ํฌ๊ธฐ๊ฐ€ 0์ธ์ง€ ํ™•์ธํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค. import java.util.List; import java.util.ArrayList; public class Main { public static void main(String[] args) { // ๋นˆ List ์ƒ์„ฑ List list = new ArrayList(); // isEmpty() ๋ฉ”์„œ๋“œ ์‚ฌ์šฉ if (list.isEmpty()) { System.out.println("List is empty"); } else { System.out.println(..

JAVA 2024.03.25

[DB][MySQL] NULLIF

mysql ์—์„œ IFNULL๋กœ null ๊ฐ’์ด๋ฉด '0'๊ฐ’์„ default ๋กœ ์„ค์ •ํ•˜๊ณ  ์‹ถ์€๋ฐ ๋นˆ๊ฐ’์ด ๋“ค์–ด๊ฐ”๋‹ค. ๋นˆ๊ฐ’์€ IFNULL์— ๊ฑธ๋ฆฌ์ง€๊ฐ€ ์•Š๋Š”๋‹ค๋Š” ๊ฒƒ์„ ์•Œ๊ฒŒ๋๋‹ค. ๋นˆ ๋ฌธ์ž์—ด("")์€ NULL์ด ์•„๋‹ˆ๊ธฐ ๋•Œ๋ฌธ์— IFNULL(NULLIF(#{param.askTp}, ''), '0') ์ด๋ ‡๊ฒŒํ•˜๋ฉด ๋œ๋‹ค.

DB 2024.03.24

[jQuery] toggleClass()

https://www.codingfactory.net/10295 jQuery / Method / .toggleClass() - ์„ ํƒํ•œ ์š”์†Œ์— ํด๋ž˜์Šค ๊ฐ’์„ ๋„ฃ์—ˆ๋‹ค ๋บ๋‹ค ํ•˜๋Š” ๋ฉ”์„œ๋“œ .toggleClass() .toggleClass()๋กœ ์„ ํƒํ•œ ์š”์†Œ์— ํด๋ž˜์Šค(Class) ๊ฐ’์„ ๋„ฃ์—ˆ๋‹ค ๋บ๋‹ค ํ•  ์ˆ˜ ์žˆ์Šต๋‹ˆ๋‹ค. ๋ฌธ๋ฒ• .toggleClass( className ) ์˜ˆ๋ฅผ ๋“ค์–ด $( 'p' ).toggleClass( 'xyz' ); ๋Š”, p ์š”์†Œ์— xyz ํด๋ž˜์Šค๊ฐ€ ์—†์œผ๋ฉด ์ถ”๊ฐ€ํ•˜๊ณ , ์žˆ www.codingfactory.net $(this).toggleClass('col-lg-4 col-lg-6'); toggleClass ์•ˆ์— ํด๋ž˜์Šค๋ช…์ด ์žˆ์œผ๋ฉด ์ œ๊ฑฐํ•˜๊ณ  ์—†์œผ๋ฉด ์ถ”๊ฐ€ํ•œ๋‹ค. col-lg-4 ํด๋ž˜์Šค๋ฅผ ๊ฐ–๊ณ ์žˆ๋˜ ์š”์†Œ๋Š” col-l..

Front/JS & jQuery 2024.03.23

[js] Number.isNaN()

https://developer.mozilla.org/ko/docs/Web/JavaScript/Reference/Global_Objects/Number/isNaN Number.isNaN() - JavaScript | MDN Number.isNaN() ๋ฉ”์„œ๋“œ๋Š” ์ฃผ์–ด์ง„ ๊ฐ’์ด NaN์ธ์ง€ ํŒ๋ณ„ํ•ฉ๋‹ˆ๋‹ค. ๊ธฐ์กด๋ถ€ํ„ฐ ์กด์žฌํ•œ ์ „์—ญ isNaN() ํ•จ์ˆ˜์˜ ๋” ์—„๊ฒฉํ•œ ๋ฒ„์ „์ž…๋‹ˆ๋‹ค. developer.mozilla.org

Front/JS & jQuery 2024.03.22
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