feat(common): add a tool method encode

hugegraph-common/src/main/java/org/apache/hugegraph/rest/AbstractRestClient.java

@@ -19,7 +19,10 @@
 
 import java.io.FileInputStream;
 import java.io.IOException;
+import java.io.UnsupportedEncodingException;
 import java.net.URI;
+import java.net.URLEncoder;
+import java.nio.charset.StandardCharsets;
 import java.security.KeyStore;
 import java.util.Arrays;
 import java.util.Collection;
@@ -411,6 +414,14 @@ public void close() {
         }
     }
 
+    public static String encode(String raw) {
+        try {
+            return URLEncoder.encode(raw, StandardCharsets.UTF_8.toString()).replace("+", "%2B");
+        } catch (UnsupportedEncodingException e) {
+            throw new IllegalArgumentException("Failed to encode string: " + raw, e);
+        }
+    }
+
     public void resetAuthContext() {
         this.authContext.remove();
     }

hugegraph-common/src/test/java/org/apache/hugegraph/unit/UnitTestSuite.java

@@ -22,6 +22,7 @@
 import org.apache.hugegraph.unit.config.HugeConfigTest;
 import org.apache.hugegraph.unit.config.OptionSpaceTest;
 import org.apache.hugegraph.unit.event.EventHubTest;
+import org.apache.hugegraph.unit.rest.AbstractRestClientTest;
 import org.apache.hugegraph.unit.version.VersionTest;
 import org.junit.runner.RunWith;
 import org.junit.runners.Suite;
@@ -83,6 +84,7 @@
     EventHubTest.class,
     PerfUtilTest.class,
     StopwatchTest.class,
+    AbstractRestClientTest.class,
     RestClientTest.class,
     RestResultTest.class,
     VersionTest.class,

hugegraph-common/src/test/java/org/apache/hugegraph/unit/rest/AbstractRestClientTest.java

@@ -0,0 +1,57 @@
+/*
+ * Licensed to the Apache Software Foundation (ASF) under one or more
+ * contributor license agreements. See the NOTICE file distributed with this
+ * work for additional information regarding copyright ownership. The ASF
+ * licenses this file to You under the Apache License, Version 2.0 (the
+ * "License"); you may not use this file except in compliance with the License.
+ * You may obtain a copy of the License at
+ *
+ *     http://www.apache.org/licenses/LICENSE-2.0
+ *
+ * Unless required by applicable law or agreed to in writing, software
+ * distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
+ * WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
+ * License for the specific language governing permissions and limitations
+ * under the License.
+ */
+
+package org.apache.hugegraph.unit.rest;
+
+import org.apache.hugegraph.rest.AbstractRestClient;
+import org.junit.Assert;
+import org.junit.Test;
+
+public class AbstractRestClientTest {
+
+    @Test
+    public void testEncodeWithSpaces() {
+        String raw = "hello world";
+        String expected = "hello%2Bworld";
+        String encoded = AbstractRestClient.encode(raw);
+        Assert.assertEquals(expected, encoded);
+    }
+
+    @Test
+    public void testEncodeWithSpecialCharacters() {
+        String raw = "hello@world!";
+        String expected = "hello%40world%21";
+        String encoded = AbstractRestClient.encode(raw);
+        Assert.assertEquals(expected, encoded);
+    }
+
+    @Test
+    public void testEncodeWithChineseCharacters() {
+        String raw = "你好";
+        String expected = "%E4%BD%A0%E5%A5%BD";
+        String encoded = AbstractRestClient.encode(raw);
+        Assert.assertEquals(expected, encoded);
+    }
+
+    @Test
+    public void testEncodeWithNullInput() {
+        String raw = null;
+        Assert.assertThrows(NullPointerException.class, () -> {
+            AbstractRestClient.encode(raw);
+        });
+    }
+}