[ISSUE #1699] Fix wrong topic max length in TopicValidator (#1700)

* fix(topicValidator):fix topic max length to 127

* test(topicValidator):modify relate tests

broker/src/main/java/org/apache/rocketmq/broker/topic/TopicValidator.java

@@ -27,7 +27,7 @@ public class TopicValidator {
 
     private static final String VALID_PATTERN_STR = "^[%|a-zA-Z0-9_-]+$";
     private static final Pattern PATTERN = Pattern.compile(VALID_PATTERN_STR);
-    private static final int CHARACTER_MAX_LENGTH = 255;
+    private static final int TOPIC_MAX_LENGTH = 127;
 
     private static boolean regularExpressionMatcher(String origin, Pattern pattern) {
         if (pattern == null) {
@@ -51,9 +51,9 @@ public class TopicValidator {
             return false;
         }
 
-        if (topic.length() > CHARACTER_MAX_LENGTH) {
+        if (topic.length() > TOPIC_MAX_LENGTH) {
             response.setCode(ResponseCode.SYSTEM_ERROR);
-            response.setRemark("The specified topic is longer than topic max length 255.");
+            response.setRemark("The specified topic is longer than topic max length.");
             return false;
         }
 

broker/src/test/java/org/apache/rocketmq/broker/topic/TopicValidatorTest.java

@@ -47,10 +47,10 @@ public class TopicValidatorTest {
         assertThat(response.getRemark()).contains("The specified topic is conflict with AUTO_CREATE_TOPIC_KEY_TOPIC.");
 
         clearResponse(response);
-        res = TopicValidator.validateTopic(generateString(255), response);
+        res = TopicValidator.validateTopic(generateString(128), response);
         assertThat(res).isFalse();
         assertThat(response.getCode()).isEqualTo(ResponseCode.SYSTEM_ERROR);
-        assertThat(response.getRemark()).contains("The specified topic is longer than topic max length 255.");
+        assertThat(response.getRemark()).contains("The specified topic is longer than topic max length.");
 
     }