Incompatible Jackson version: 2.9.0

场景

配置完scala(2.11)和spark(2.2.0)的windows环境后,写了个worldcount案例。加入以下依赖，然后编写wordcount

    <properties>
        <spark-version>2.2.0</spark-version>
        <scala-version>2.11</scala-version>
    </properties>

    <dependencies>
            <!-- https://mvnrepository.com/artifact/org.apache.spark/spark-core -->
            <dependency>
                <groupId>org.apache.spark</groupId>
                <artifactId>spark-core_${scala-version}</artifactId>
                <version>${spark-version}</version>
            </dependency>
    </dependencies>

import org.apache.spark.rdd.RDD
import org.apache.spark.{SparkConf, SparkContext}

/**
 * @Author 晓风
 * @Date 2021/10/8 22:37
 * @Version 1.0
 */
object WorldCount {
    def main(args: Array[String]): Unit = {

        // 配置相关信息
        val sparkConf:SparkConf = new SparkConf().setMaster("local").setAppName("wordCount")

        // 获取上下文
        val sc: SparkContext = new SparkContext(sparkConf)

/*        // 读取文件
        val lines: RDD[String] = sc.textFile("data/helloworld")
        // 切分，flatmap
        val worlds: RDD[String] = lines.flatMap(_.split(" "))
        // map
        val worldTuple: RDD[(String, Int)] = worlds.map((_, 1))
        // reduce
        val value: RDD[(String, Int)] = worldTuple.reduceByKey((_ + _))
        // 打印
       value.foreach(println)
*/

        //hello scala
        //hello java
        //hello spark
        //hello flink
        //hello world
        sc.textFile("data/helloworld").flatMap(_.split(" ")).map((_,1)).reduceByKey(_ + _).foreach(println)
        // 关闭连接
        sc.stop()

    }
}

• 报错

Caused by: java.lang.NoClassDefFoundError: com/fasterxml/jackson/annotation/JsonMerge

• 加入依赖

     <dependency>
                  <groupId>com.fasterxml.jackson.core</groupId>
                  <artifactId>jackson-databind</artifactId>
                  <version>2.9.0</version>
              </dependency>
  
              <dependency>
                  <groupId>com.fasterxml.jackson.core</groupId>
                  <artifactId>jackson-core</artifactId>
                  <version>2.9.0</version>
              </dependency>
              <dependency>
                  <groupId>com.fasterxml.jackson.core</groupId>
                  <artifactId>jackson-annotations</artifactId>
                  <version>2.9.0</version>
      </dependency>
  

• 报错

Caused by: com.fasterxml.jackson.databind.JsonMappingException: Incompatible Jackson version: 2.9.0

• 加入依赖

            <dependency>
                  <groupId>com.fasterxml.jackson.module</groupId>
                  <artifactId>jackson-module-scala_2.11</artifactId>
                  <version>2.9.0</version>
            </dependency>
  
  

最终依赖

```properties
<properties>
    <spark-version>2.2.0</spark-version>
    <scala-version>2.11</scala-version>
</properties>

<dependencies>
        <!-- https://mvnrepository.com/artifact/org.apache.spark/spark-core -->
        <dependency>
            <groupId>org.apache.spark</groupId>
            <artifactId>spark-core_${scala-version}</artifactId>
            <version>${spark-version}</version>
        </dependency>

         <dependency>
             <groupId>com.fasterxml.jackson.module</groupId>
             <artifactId>jackson-module-scala_2.11</artifactId>
             <version>2.9.0</version>
         </dependency>


</dependencies>

```

原因

• jackson.databind版本与 jackson.module版本不匹配