fixes #2277 move MapUtil to light-4j utility module

utility/src/main/java/com/networknt/utility/MapUtil.java

@@ -0,0 +1,30 @@
+package com.networknt.utility;
+import java.util.Iterator;
+import java.util.Map;
+import java.util.Objects;
+import java.util.Optional;
+
+public class MapUtil {
+    // Method to get value from HashMap with case-insensitive key lookup
+    public static <V> Optional<V> getValueIgnoreCase(Map<String, V> map, String key) {
+        for (Map.Entry<String, V> entry : map.entrySet()) {
+            if (Objects.equals(entry.getKey().toLowerCase(), key.toLowerCase())) {
+                return Optional.of(entry.getValue());
+            }
+        }
+        return Optional.empty();
+    }
+
+    // Method to delete value from HashMap with case-insensitive key lookup
+    public static <V> Optional<V> delValueIgnoreCase(Map<String, V> map, String key) {
+        for(Iterator<Map.Entry<String, V>> it = map.entrySet().iterator(); it.hasNext(); ) {
+            Map.Entry<String, V> entry = it.next();
+            if (Objects.equals(entry.getKey().toLowerCase(), key.toLowerCase())) {
+                it.remove();
+                return Optional.of(entry.getValue());
+            }
+        }
+        return Optional.empty();
+    }
+
+}

utility/src/test/java/com/networknt/utility/MapUtilTest.java

@@ -0,0 +1,26 @@
+package com.networknt.utility;
+
+
+import org.junit.Assert;
+import org.junit.Test;
+
+import java.util.HashMap;
+import java.util.Map;
+import java.util.Optional;
+
+import static com.networknt.utility.MapUtil.getValueIgnoreCase;
+
+public class MapUtilTest {
+    @Test
+    public void testGetValueIgnoreCase() {
+        Map<String, String> hashMap = new HashMap<>();
+        hashMap.put("Key1", "Value1");
+        hashMap.put("Key2", "Value2");
+
+        // Get value from HashMap with case-insensitive key lookup
+        String key = "key1";
+        Optional<String> value = getValueIgnoreCase(hashMap, key);
+        Assert.assertTrue(value.isPresent());
+    }
+
+}