创建IntelliJ IDEA项目
选择maven
image填写groupId和artifactId
image填写项目名称和项目路径
image修改pom.xml
文件
<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.zhyoulun</groupId>
<artifactId>storm_study</artifactId>
<version>1.0-SNAPSHOT</version>
<dependencies>
<dependency>
<groupId>org.apache.storm</groupId>
<artifactId>storm-core</artifactId>
<version>0.9.7</version>
</dependency>
</dependencies>
</project>
编写Topology
、Spout
、Bolt
文件
模型图为
image代码位置
imageMainTopology.java
文件
import backtype.storm.Config;
import backtype.storm.LocalCluster;
import backtype.storm.topology.TopologyBuilder;
public class MainTopology {
public void runLocal(int waitSeconds) {
TopologyBuilder builder = new TopologyBuilder();
builder.setSpout("wordSpout", new WordSpout(), 1);
builder.setBolt("countBolt", new CountBolt(), 1).shuffleGrouping("wordSpout");
Config config = new Config();
LocalCluster cluster = new LocalCluster();
cluster.submitTopology("word_count", config, builder.createTopology());
try {
Thread.sleep(waitSeconds * 1000);
} catch (InterruptedException e) {
e.printStackTrace();
}
cluster.killTopology("word_count");
cluster.shutdown();
}
public static void main(String[] args) {
MainTopology topology = new MainTopology();
topology.runLocal(60);
}
}
WordSpout.java
文件
import backtype.storm.spout.SpoutOutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichSpout;
import backtype.storm.tuple.Fields;
import backtype.storm.tuple.Values;
import java.util.Map;
public class WordSpout extends BaseRichSpout {
private SpoutOutputCollector collector;
private String[] words = {"hello","world","storm","study"};//单词池
private int index = 0;
public void open(Map map, TopologyContext topologyContext, SpoutOutputCollector spoutOutputCollector) {
this.collector = spoutOutputCollector;
}
public void nextTuple() {
this.collector.emit(new Values(this.words[index]));
index++;
if(index>=words.length){
index = 0;
}
//等待500ms
try {
Thread.sleep(500);
} catch (InterruptedException e) {
e.printStackTrace();
}
}
public void declareOutputFields(OutputFieldsDeclarer outputFieldsDeclarer) {
outputFieldsDeclarer.declare(new Fields("word"));
}
}
CountBolt.java
文件
import backtype.storm.task.OutputCollector;
import backtype.storm.task.TopologyContext;
import backtype.storm.topology.OutputFieldsDeclarer;
import backtype.storm.topology.base.BaseRichBolt;
import backtype.storm.tuple.Tuple;
import java.util.HashMap;
import java.util.Map;
import java.util.Set;
public class CountBolt extends BaseRichBolt {
private HashMap<String, Integer> wordMap = new HashMap<String, Integer>();
public void prepare(Map map, TopologyContext topologyContext, OutputCollector outputCollector) {
}
public void execute(Tuple tuple) {
//从tuple中读取单词
String word = tuple.getStringByField("word");
//计数
int num;
if (wordMap.containsKey(word)) {
num = wordMap.get(word);
} else {
num = 0;
}
wordMap.put(word, 1 + num);
//输出展示
Set<String> keys = wordMap.keySet();
for (String key : keys) {
System.out.print(key + ":" + wordMap.get(key) + ",");
}
System.out.println();
}
public void declareOutputFields(OutputFieldsDeclarer outputFieldsDeclarer) {
}
}
运行结果
...
6709 [Thread-11-wordSpout] INFO backtype.storm.daemon.executor - Activating spout wordSpout:(3)
hello:1,
world:1,hello:1,
world:1,storm:1,hello:1,
study:1,world:1,storm:1,hello:1,
study:1,world:1,storm:1,hello:2,
study:1,world:2,storm:1,hello:2,
study:1,world:2,storm:2,hello:2,
study:2,world:2,storm:2,hello:2,
study:2,world:2,storm:2,hello:3,
study:2,world:3,storm:2,hello:3,
study:2,world:3,storm:3,hello:3,
...
study:27,world:27,storm:27,hello:28,
study:27,world:28,storm:27,hello:28,
study:27,world:28,storm:28,hello:28,
study:28,world:28,storm:28,hello:28,
study:28,world:28,storm:28,hello:29,
study:28,world:29,storm:28,hello:29,
study:28,world:29,storm:29,hello:29,
study:29,world:29,storm:29,hello:29,
64515 [main] INFO backtype.storm.daemon.nimbus - Delaying event :remove for 30 secs for word_count-1-1511504981
...
问题
java.lang.NoClassDefFoundError: backtype/storm/topology/IRichSpout
如果pom.xml
中的dependencies
部分如下所示:
<dependencies>
<dependency>
<groupId>org.apache.storm</groupId>
<artifactId>storm-core</artifactId>
<version>0.9.7</version>
<scope>provided</scope>
</dependency>
</dependencies>
将会报出这个错误,详细内容如下所示:
java.lang.NoClassDefFoundError: backtype/storm/topology/IRichSpout
at java.lang.Class.getDeclaredMethods0(Native Method)
at java.lang.Class.privateGetDeclaredMethods(Class.java:2701)
at java.lang.Class.privateGetMethodRecursive(Class.java:3048)
at java.lang.Class.getMethod0(Class.java:3018)
at java.lang.Class.getMethod(Class.java:1784)
at sun.launcher.LauncherHelper.validateMainClass(LauncherHelper.java:544)
at sun.launcher.LauncherHelper.checkAndLoadMain(LauncherHelper.java:526)
Caused by: java.lang.ClassNotFoundException: backtype.storm.topology.IRichSpout
at java.net.URLClassLoader.findClass(URLClassLoader.java:381)
at java.lang.ClassLoader.loadClass(ClassLoader.java:424)
at sun.misc.Launcher$AppClassLoader.loadClass(Launcher.java:335)
at java.lang.ClassLoader.loadClass(ClassLoader.java:357)
... 7 more
Error: A JNI error has occurred, please check your installation and try again
Exception in thread "main"
解决这个问题需要把<scope>provided</scope>
删掉。指定该属性的意思是,运行环境已经提供了相应的依赖,该依赖不会被打进jar包中。而在intellij中运行本地模式时,需要删掉这个属性,否则会找不到类。
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