Map searchForm = new HashMap();searchForm.put("name", "Alice");boolean result = searchForm.containsKey("name"); // true

entrySet() 이용// Filter entries with keys starting with "DATA"Map filteredMap = searchForm.entrySet() .stream() .filter(entry -> entry.getKey().startsWith("DATA")) .collect(Collectors.toMap(Map.Entry::getKey, Map.Entry::getValue));for문 이용// Extract keys into a list for iterationList keys = new ArrayList(searchForm.keySet());// Result map to store filtered entriesMap filteredM..

Arrays.asList 이용String[] array = {"apple", "banana", "cherry"};String valueToCheck = "banana";boolean isIncluded = Arrays.asList(array).contains(valueToCheck);if (isIncluded) { System.out.println(valueToCheck + " is in the array.");} else { System.out.println(valueToCheck + " is not in the array.");}for문 이용String[] array = {"apple", "banana", "cherry"};String valueToCheck = "banana";boolea..

public boolean isNumeric(String str) { return str != null && str.matches("\\d+(\\.\\d+)?");}

import java.net.URLEncoder;import java.nio.charset.StandardCharsets;public class URLEncoderExample { public static void main(String[] args) { try { String value = "Hello World!"; String encodedValue = URLEncoder.encode(value, StandardCharsets.UTF_8); System.out.println(encodedValue); // Output: Hello+World%21 } catch (Exception e) { e...

핸드폰에서 찍은 이미지를 서버에 업로드시 width, height 정보를 가져올때, EXIF orientation를 고려해야 함그냥 width, height 정보를 가져오면, 옆으로 돌려서 찍은 사진의 경우 width와 height가 바껴서 나옴pom.xml com.drewnoakes metadata-extractor 2.18.0 Javaimport com.drew.imaging.ImageMetadataReader;import com.drew.metadata.Directory;import com.drew.metadata.Metadata;import com.drew.metadata.Tag;import com.drew.metadata.exif.ExifIFD..