fix diff method can not be added to RadixTree

Author: Stellar1999

dubbo-rpc/dubbo-rpc-triple/src/main/java/org/apache/dubbo/rpc/protocol/tri/rest/mapping/DefaultRequestMappingRegistry.java

@@ -169,7 +169,7 @@ private void register0(RequestMapping mapping, HandlerMeta handler, AtomicIntege
         try {
             Registration registration = new Registration(mapping, handler);
             for (PathExpression path : mapping.getPathCondition().getExpressions()) {
-                Registration exists = tree.addPath(path, registration);
+                Registration exists = tree.addPath(path, registration, Registration::equals);
                 if (exists == null) {
                     counter.incrementAndGet();
                     if (LOGGER.isDebugEnabled()) {

dubbo-rpc/dubbo-rpc-triple/src/main/java/org/apache/dubbo/rpc/protocol/tri/rest/mapping/RadixTree.java

@@ -32,6 +32,7 @@
 import java.util.Map;
 import java.util.Map.Entry;
 import java.util.function.BiConsumer;
+import java.util.function.BiFunction;
 import java.util.function.Predicate;
 
 /**
@@ -63,7 +64,18 @@ public RadixTree() {
         this(true, '/');
     }
 
+    /**
+     * This is a default implementation that does not check for equality.
+     */
     public T addPath(PathExpression path, T value) {
+        return addPath(path, value, (t, t2) -> Boolean.TRUE);
+    }
+
+    /**
+     * When equalFunction is not null, if a node is found at the path, it will not be returned immediately; <br/>
+     * instead, whether to return it depends on the result of the function.
+     */
+    public T addPath(PathExpression path, T value, BiFunction<T, T, Boolean> equalFunction) {
         if (path.isDirect()) {
             KeyString key = new KeyString(path.getPath(), caseSensitive);
             List<Match<T>> matches = directPathMap.computeIfAbsent(key, k -> new ArrayList<>());
@@ -83,9 +95,16 @@ public T addPath(PathExpression path, T value) {
             Node<T> child = getChild(current, segments[i]);
             if (i == len - 1) {
                 List<Pair<PathExpression, T>> values = child.values;
-                for (int j = 0, size = values.size(); j < size; j++) {
-                    if (values.get(j).getLeft().equals(path)) {
-                        return values.get(j).getRight();
+                for (Pair<PathExpression, T> pathExpressionTPair : values) {
+                    if (pathExpressionTPair.getLeft().equals(path)) {
+                        T rightVal = pathExpressionTPair.getRight();
+                        if (equalFunction == null) {
+                            return rightVal;
+                        } else {
+                            if (equalFunction.apply(rightVal, value)) {
+                                return rightVal;
+                            }
+                        }
                     }
                 }
                 values.add(Pair.of(path, value));