[Bug][KafkaSource]Failed to parse offset format (apache#3810)

* When the kafka source is started in offset mode, when the topicName has a "-", the exception will be resolved, causing the assignment to fail

* fix code style.

* update change-log

Co-authored-by: zhaoliang01 <zhaoliang01@58.com>

docs/en/connector-v2/source/kafka.md

@@ -210,3 +210,4 @@ source {
 
 - [Improve] Support setting read starting offset or time at startup config ([3157](https://github.com/apache/incubator-seatunnel/pull/3157))
 - [Improve] Support for dynamic discover topic & partition in streaming mode ([3125](https://github.com/apache/incubator-seatunnel/pull/3125))
+- [Bug] Fixed the problem that parsing the offset format failed when the startup mode was offset([3810](https://github.com/apache/incubator-seatunnel/pull/3810))

seatunnel-connectors-v2/connector-kafka/src/main/java/org/apache/seatunnel/connectors/seatunnel/kafka/source/KafkaSource.java

@@ -137,9 +137,11 @@ public void prepare(Config config) throws PrepareFailException {
                     Map<TopicPartition, Long> specificStartOffsets = new HashMap<>();
                     ObjectNode jsonNodes = JsonUtils.parseObject(offsetsJson);
                     jsonNodes.fieldNames().forEachRemaining(key -> {
-                        String[] topicAndPartition = key.split("-");
+                        int splitIndex = key.lastIndexOf("-");
+                        String topic = key.substring(0, splitIndex);
+                        String partition = key.substring(splitIndex + 1);
                         long offset = jsonNodes.get(key).asLong();
-                        TopicPartition topicPartition = new TopicPartition(topicAndPartition[0], Integer.valueOf(topicAndPartition[1]));
+                        TopicPartition topicPartition = new TopicPartition(topic, Integer.valueOf(partition));
                         specificStartOffsets.put(topicPartition, offset);
                     });
                     this.metadata.setSpecificStartOffsets(specificStartOffsets);

seatunnel-connectors-v2/connector-kafka/src/test/java/org/apache/seatunnel/connectors/seatunnel/kafka/KafkaStartOffsetTest.java

@@ -0,0 +1,36 @@
+/*
+ * 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.seatunnel.connectors.seatunnel.kafka;
+
+import org.junit.jupiter.api.Assertions;
+import org.junit.jupiter.api.Test;
+
+public class KafkaStartOffsetTest {
+
+    @Test
+    void getTopicNameAndPartition(){
+        String topicName = "my-topic-test";
+        int partIndex = 1;
+        String key = "my-topic-test-1";
+        int splitIndex = key.lastIndexOf("-");
+        String topic = key.substring(0, splitIndex);
+        String partition = key.substring(splitIndex + 1);
+        Assertions.assertEquals(topic, topicName);
+        Assertions.assertEquals(Integer.valueOf(partition), partIndex);
+    }
+}