fix: handle null password in MqttContext.isValid to avoid NPE

shenyu-protocol/shenyu-protocol-mqtt/pom.xml

@@ -46,6 +46,12 @@
             <artifactId>reflections</artifactId>
             <version>0.9.11</version>
         </dependency>
+
+        <dependency>
+            <groupId>org.junit.jupiter</groupId>
+            <artifactId>junit-jupiter</artifactId>
+            <scope>test</scope>
+        </dependency>
     </dependencies>
 
 </project>

shenyu-protocol/shenyu-protocol-mqtt/src/main/java/org/apache/shenyu/protocol/mqtt/MqttContext.java

@@ -19,6 +19,8 @@
 
 import org.apache.commons.lang3.StringUtils;
 
+import java.util.Objects;
+
 /**
  * mqtt env.
  */
@@ -45,7 +47,7 @@ public class MqttContext {
      * @return true is correct, false unavailable.
      */
     public static boolean isValid(final String userName, final byte[] passwordInBytes) {
-        String password = new String(passwordInBytes);
+        String password = Objects.isNull(passwordInBytes) ? "" : new String(passwordInBytes);
 
         if (StringUtils.isEmpty(password) || StringUtils.isEmpty(userName)) {
             return false;

shenyu-protocol/shenyu-protocol-mqtt/src/test/java/org/apache/shenyu/protocol/mqtt/MqttContextTest.java

@@ -0,0 +1,72 @@
+/*
+ * 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.shenyu.protocol.mqtt;
+
+import org.junit.jupiter.api.BeforeEach;
+import org.junit.jupiter.api.Test;
+
+import static org.junit.jupiter.api.Assertions.assertFalse;
+import static org.junit.jupiter.api.Assertions.assertTrue;
+
+/**
+ * Test Case For {@link MqttContext}.
+ */
+public class MqttContextTest {
+
+    private static final String USER_NAME = "testUser";
+
+    private static final String PASSWORD = "testPass";
+
+    private final MqttContext mqttContext = new MqttContext();
+
+    @BeforeEach
+    public void setUp() {
+        mqttContext.setUserName(USER_NAME);
+        mqttContext.setPassword(PASSWORD);
+    }
+
+    @Test
+    public void testIsValidWithCorrectCredentials() {
+        assertTrue(MqttContext.isValid(USER_NAME, PASSWORD.getBytes()));
+    }
+
+    @Test
+    public void testIsValidWithNullPasswordInBytes() {
+        assertFalse(MqttContext.isValid(USER_NAME, null));
+    }
+
+    @Test
+    public void testIsValidWithEmptyPassword() {
+        assertFalse(MqttContext.isValid(USER_NAME, new byte[0]));
+    }
+
+    @Test
+    public void testIsValidWithWrongPassword() {
+        assertFalse(MqttContext.isValid(USER_NAME, "wrongPass".getBytes()));
+    }
+
+    @Test
+    public void testIsValidWithNullUserName() {
+        assertFalse(MqttContext.isValid(null, PASSWORD.getBytes()));
+    }
+
+    @Test
+    public void testIsValidWithEmptyUserName() {
+        assertFalse(MqttContext.isValid("", PASSWORD.getBytes()));
+    }
+}