Storm-Kafka模块常用接口分析及消费kafka数据例子
来源：程序员人生 发布时间：2015-02-10 08:39:44 阅读次数：8780次
使用storm-kafka模块读取kafka中的数据，依照以下两步进行构建(我使用的版本是0.9.3)
1. 使用BrokerHosts接口来配置kafka broker host与partition的mapping信息;
2. 使用KafkaConfig来配置1些与kafka本身相干的选项，如fetchSizeBytes、socketTimeoutMs
下面分别介绍这两块的实现：
对配置1，目前支持两种实现方式：zk配置、静态ip端口方式
第1种方式：Zk读取(比较常见)
ZkHosts支持两种创建方式，
public ZkHosts(String brokerZkStr, String brokerZkPath)
//使用默许brokerZkPath:"/brokers"
public ZkHosts(String brokerZkStr)
通过这类方式访问的时候，经过60s会刷新1下host->partition的mapping
第2步：构建KafkaConfig对象
目条件供两种构造函数，
public KafkaConfig(BrokerHosts hosts, String topic)
//clientId如果不想每次随机生成的话，就自己设置1个
public KafkaConfig(BrokerHosts hosts, String topic, String clientId)
代码参考：
//这个地方其实就是kafka配置文件里边的zookeeper.connect这个参数，可以去那里拿过来。
String brokerZkStr = "10.100.90.201:2181/kafka_online_sample";
String brokerZkPath = "/brokers";
ZkHosts zkHosts = new ZkHosts(brokerZkStr, brokerZkPath);
String topic = "mars-wap";
//以下：将offset汇报到哪一个zk集群,相应配置
// String offsetZkServers = "10.199.203.169";
String offsetZkServers = "10.100.90.201";
String offsetZkPort = "2181";
List<String> zkServersList = new ArrayList<String>();
zkServersList.add(offsetZkServers);
//汇报offset信息的root路径
String offsetZkRoot = "/stormExample";
//存储该spout id的消费offset信息,比方以topoName来命名
String offsetZkId = "storm-example";
SpoutConfig kafkaConfig = new SpoutConfig(zkHosts, topic, offsetZkRoot, offsetZkId);
kafkaConfig.zkRoot = offsetZkRoot;
kafkaConfig.zkPort = Integer.parseInt(offsetZkPort);
kafkaConfig.zkServers = zkServersList;
kafkaConfig.id = offsetZkId;
kafkaConfig.scheme = new SchemeAsMultiScheme(new StringScheme());
KafkaSpout spout = new KafkaSpout(kafkaConfig);
TopologyBuilder builder = new TopologyBuilder();
builder.setSpout("spout", spout, 1);
builder.setBolt("bolt", new Bolt(), 1).shuffleGrouping("spout");
Config config = new Config();
LocalCluster cluster = new LocalCluster();
cluster.submitTopology("test", config, builder.createTopology());
// cluster submit.
// try {
// StormSubmitter.submitTopology("storm-kafka-example",config,builder.createTopology());
// } catch (AlreadyAliveException e) {
// e.printStackTrace();
// } catch (InvalidTopologyException e) {
// e.printStackTrace();
// }
第2种方式：静态ip端口方式
String kafkaHost = "10.100.90.201";
Broker brokerForPartition0 = new Broker(kafkaHost);//localhost:9092
Broker brokerForPartition1 = new Broker(kafkaHost, 9092);//localhost:9092 but we specified the port explicitly
GlobalPartitionInformation partitionInfo = new GlobalPartitionInformation();
partitionInfo.addPartition(0, brokerForPartition0);//mapping form partition 0 to brokerForPartition0
partitionInfo.addPartition(1, brokerForPartition1);//mapping form partition 1 to brokerForPartition1
StaticHosts hosts = new StaticHosts(partitionInfo);
String topic="mars-wap";
String offsetZkRoot ="/stormExample";
String offsetZkId="staticHost";
String offsetZkServers = "10.100.90.201";
String offsetZkPort = "2181";
List<String> zkServersList = new ArrayList<String>();
zkServersList.add(offsetZkServers);
SpoutConfig kafkaConfig = new SpoutConfig(hosts,topic,offsetZkRoot,offsetZkId);
kafkaConfig.zkPort = Integer.parseInt(offsetZkPort);
kafkaConfig.zkServers = zkServersList;
kafkaConfig.scheme = new SchemeAsMultiScheme(new StringScheme());
KafkaSpout spout = new KafkaSpout(kafkaConfig);
TopologyBuilder builder = new TopologyBuilder();
builder.setSpout("spout", spout, 1);
builder.setBolt("bolt", new Bolt(), 1).shuffleGrouping("spout");
Config config = new Config();
LocalCluster cluster = new LocalCluster();
cluster.submitTopology("test", config, builder.createTopology());
完全的使用例子，见github源码
https://github.com/tonylee0329/storm-example/blob/master/src/main/java/org/tony/storm_kafka/common/
参考：
https://github.com/apache/storm/blob/v0.9.3/external/storm-kafka/README.md
本文为原创，转载请标明出处！From Tony_老7
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