[Spark应用]-- 创建单例的kafka链接

一、创建一个单例的spark streaming  kafka链接类:KafkaGetStreamUtil.java

import enn.bean.SparkProperties;
import kafka.serializer.StringDecoder;
import org.apache.spark.SparkConf;
import org.apache.spark.streaming.Durations;
import org.apache.spark.streaming.api.java.JavaPairInputDStream;
import org.apache.spark.streaming.api.java.JavaStreamingContext;
import org.apache.spark.streaming.kafka.KafkaUtils;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;

/**
 * Document:本类作用---->单例模式的KafkaStream,不用每次都去创建连接
 * User: yangjf
 * Date: 2016/7/16  10:20
 */
public class KafkaGetStreamUtil {
    private static Map<String, Object> kafkaStreamMap = new HashMap<String, Object>();
    public static synchronized Map<String,Object> getKafkaStreamMap() {
        if(kafkaStreamMap.isEmpty()){
//            SparkConf conf = new SparkConf().setMaster("local[4]").setAppName("ConsumerKafkaRealData");
            SparkConf conf = new SparkConf().setAppName("ConsumerKafkaRealData").setMaster("yarn-cluster");
            JavaStreamingContext jssc = new JavaStreamingContext(conf, Durations.milliseconds(
                                                                   SparkProperties.SPARK_DSTREAM_MILLISECONDS));
            //kafka
            Set<String> topics = new HashSet<String>();
            topics.add(SparkProperties.KAFKA_TOPIC);
            Map<String,String> kafkaParams = new HashMap<String,String>();
            kafkaParams.put(SparkProperties.KAFKA_METADATA_BROKER_LIST_TXT, SparkProperties.KAFKA_BROKER_URL);
            kafkaParams.put(SparkProperties.KAFKA_SERIALIZER_CLASS, SparkProperties.KAFKA_SERIALIZER_STRINGENCODER);
            kafkaParams.put("group.id","e_lvbin");
//            kafkaParams.put("auto.offset.reset", "smallest");/**保证可以读取丢失的数据*/
            JavaPairInputDStream directKafkaStream =
                    KafkaUtils.createDirectStream(jssc, String.class, String.class, 
                                                 StringDecoder.class, StringDecoder.class, kafkaParams, topics);

            //可迭代对象数据
            kafkaStreamMap.put("directKafkaStream",directKafkaStream);
            kafkaStreamMap.put("jssc",jssc);

            return kafkaStreamMap;
        }else {
            return kafkaStreamMap;
        }
    }
   }

SparkProperties.java文件内容：

import java.io.Serializable; /**  * Document:本类作用---->--->开发环境的配置文件  * User: yangjf  * Date: 2016072016/7/119:43  */ public class SparkProperties implements Serializable { /**spark相关*/  public static long SPARK_DSTREAM_MILLISECONDS=200;//毫秒  /**kafka相关*/  public static String KAFKA_TOPIC="20160710aa"; //topic名称10.37.149.180  public static String KAFKA_BROKER_URL="elcndc2bdkf01t:9092";//kafka地址，可以是列表 // public static String KAFKA_BROKER_URL="10.37.149.180:9092";//kafka地址，可以是列表  public static String KAFKA_METADATA_BROKER_LIST_TXT="metadata.broker.list"; public static String KAFKA_SERIALIZER_CLASS="serializer.class"; public static String KAFKA_SERIALIZER_STRINGENCODER="kafka.serializer.StringEncoder"; /**zookeeper相关本地测试使用*/  public static String ZOOKEEPER_URL="node1:2180,node2:2180,node3:2180"; public static String HADOOP_NAMENODE="hdfs://node1:9000/"; /**redis相关*/  public static String REDIS_HOST="elcndc2bdrd01t"; //redis master的ip地址：10.37.149.184  public static Integer REDIS_PORT=6379; public static Integer REDIS_TIMEOUT=30000; }

二、使用单例模式的类创建kafka链接；核心代码如下

JavaPairInputDStream directKafkaStream = (JavaPairInputDStream) KafkaGetStreamUtil.getKafkaStreamMap().get("directKafkaStream");
JavaStreamingContext jssc = (JavaStreamingContext) KafkaGetStreamUtil.getKafkaStreamMap().get("jssc");
JavaDStream<JSONObject> lines = directKafkaStream.map(new Function<Tuple2<String, String>, JSONObject>() {
    @Override
    public JSONObject call(Tuple2<String, String> tuple2) {
        return JSONObject.fromObject(tuple2._2);

    }
});