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* 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.flink.examples.java.wordcount;
import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.java.DataSet;
import org.apache.flink.api.java.ExecutionEnvironment;
import org.apache.flink.api.java.utils.ParameterTool;
import org.apache.flink.core.fs.FileSystem.WriteMode;
import org.apache.flink.examples.java.wordcount.WordCountData;
import org.apache.flink.util.Collector;
/**
* This example shows an implementation of WordCount without using the Tuple2 type, but a custom
* class.
*/
@SuppressWarnings("serial")
public class WordCountPojo {
/**
* This is the POJO (Plain Old Java Object) that is being used for all the operations. As long
* as all fields are public or have a getter/setter, the system can handle them
*/
public static class Word {
// fields
private String word;
private int frequency;
// constructors
public Word() {}
public Word(String word, int i) {
this.word = word;
this.frequency = i;
}
// getters setters
public String getWord() {
return word;
}
public void setWord(String word) {
this.word = word;
}
public int getFrequency() {
return frequency;
}
public void setFrequency(int frequency) {
this.frequency = frequency;
}
@Override
public String toString() {
return "Word=" + word + " freq=" + frequency;
}
}
public static void main(String[] args) throws Exception {
final ParameterTool params = ParameterTool.fromArgs(args);
// set up the execution environment
final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
// make parameters available in the web interface
env.getConfig().setGlobalJobParameters(params);
// get input data
DataSet<String> text;
if (params.has("input")) {
// read the text file from given input path
text = env.readTextFile(params.get("input"));
} else {
// get default test text data
System.out.println("Executing WordCount example with default input data set.");
System.out.println("Use --input to specify file input.");
text = WordCountData.getDefaultTextLineDataSet(env);
}
DataSet<Word> counts =
// split up the lines into Word objects (with frequency = 1)
text.flatMap(new Tokenizer())
// group by the field word and sum up the frequency
.groupBy("word")
.reduce(
new ReduceFunction<Word>() {
@Override
public Word reduce(Word value1, Word value2) throws Exception {
return new Word(
value1.word, value1.frequency + value2.frequency);
}
});
if (params.has("output")) {
counts.writeAsText(params.get("output"), WriteMode.OVERWRITE);
// execute program
env.execute("WordCount-Pojo Example");
} else {
System.out.println("Printing result to stdout. Use --output to specify output path.");
counts.print();
}
}
// *************************************************************************
// USER FUNCTIONS
// *************************************************************************
/**
* Implements the string tokenizer that splits sentences into words as a user-defined
* FlatMapFunction. The function takes a line (String) and splits it into multiple Word objects.
*/
public static final class Tokenizer implements FlatMapFunction<String, Word> {
@Override
public void flatMap(String value, Collector<Word> out) {
// normalize and split the line
String[] tokens = value.toLowerCase().split("\\W+");
// emit the pairs
for (String token : tokens) {
if (token.length() > 0) {
out.collect(new Word(token, 1));
}
}
}
}
}
flink-batch-wordcount.rar （5个子文件） 
flink-batch-wordcount 
pom.xml 19KB flink-batch-wordcount.iml 9KB src test java main resources java org apache flink examples java wordcount WordCountData.java 3KB WordCount.java 5KB WordCountPojo.java 5KB资源评论
