java Flink（一）实现数据集简单demo

淩亂°似流年 2022-11-12 09:40 302阅读 0赞

**今天开始学习Flink，入手第一个Flink数据集demo**

**功能：把文件中的单词进行分词，统计个数**

**基本思路：读取文件内容-》数据集-》数据集统计二元组输出（word，count）**

**1、构建maven Flink项目**

引入Flink依赖

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzcxNTY3_size_16_color_FFFFFF_t_70][]

<dependencies>
            <dependency>
                <groupId>org.apache.flink</groupId>
                <artifactId>flink-java</artifactId>
                <version>1.10.1</version>
            </dependency>
            <dependency>
                <groupId>org.apache.flink</groupId>
                <artifactId>flink-streaming-java_2.12</artifactId>
                <version>1.10.1</version>
            </dependency>
        </dependencies>

2、 添加单词文件

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzcxNTY3_size_16_color_FFFFFF_t_70 1][]

文件内容：

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzcxNTY3_size_16_color_FFFFFF_t_70 2][]

3、进行分词处理

![watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzQwNzcxNTY3_size_16_color_FFFFFF_t_70 3][]

import org.apache.flink.api.common.functions.FlatMapFunction;
    import org.apache.flink.api.java.DataSet;
    import org.apache.flink.api.java.ExecutionEnvironment;
    import org.apache.flink.api.java.operators.DataSource;
    import org.apache.flink.api.java.tuple.Tuple2;
    import org.apache.flink.util.Collector;
    import scala.Int;
    
    /**
     * 单次统计
     * 批处理
     */
    public class WordCount {
        public static void main(String[] args) throws Exception{
            //创建执行环境
            ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
            //从文件中读取数据
            String inputPath = "D:\\idle\\FlinkTest\\src\\main\\resources\\word.txt";
            DataSet<String> inputDataSet = env.readTextFile(inputPath);
            //对数据集进行处理，按照空格进行分词，转换成（word，1）二元组进行统计
            DataSet<Tuple2<String, Integer>> resultSet = inputDataSet.flatMap(new MyflatMapper())
                    .groupBy(0) //按照第一个位置的word分组
            .sum(1); //讲第二个位置上的数据求和
    
            resultSet.print();
    
        }
    
        //自定义类，实现FlatMapFunction接口
        public static class MyflatMapper implements FlatMapFunction<String, Tuple2<String, Integer>>{
    
            public void flatMap(String s, Collector<Tuple2<String, Integer>> collector) throws Exception {
                //按空格分词
                String[] words = s.split(" ");
                //遍历所有word，包成二元组输出
                for(String word:words){
                    collector.collect(new Tuple2<String, Integer>(word, 1));
                }
            }
        }
    }

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