基于Java开发Flink篇

package com.hj.flink;

import org.apache.flink.api.common.functions.FilterFunction;
import org.apache.flink.api.common.functions.MapFunction;
import org.apache.flink.api.common.functions.ReduceFunction;
import org.apache.flink.api.java.functions.KeySelector;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.utils.ParameterTool;
import org.apache.flink.streaming.api.TimeCharacteristic;
import org.apache.flink.streaming.api.datastream.DataStream;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.streaming.api.functions.AssignerWithPunctuatedWatermarks;
import org.apache.flink.streaming.api.watermark.Watermark;
import org.apache.flink.streaming.api.windowing.assigners.TumblingEventTimeWindows;
import org.apache.flink.streaming.api.windowing.time.Time;



public class FlinkStreamJavaExample {

	public static void main(String[] args) throws Exception {
		// TODO Auto-generated method stub
		// 读取文本路径信息，并用逗号隔开
		final String[] filePaths = ParameterTool.fromArgs(args).get("filePath", "/opt/log1.txt,/opt/log2.txt").split(",");
		
		assert filePaths.length > 0;
		
		// WindowTime是设置窗口时间大小，默认情况下2分钟一个从窗口足够读取文本内容的所有信息
		final int windowTime = ParameterTool.fromArgs(args).getInt("windowTime", 2);
		
		// 构建运行环境，使用Environment处理窗口数据
		final StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
		env.setStreamTimeCharacteristic(TimeCharacteristic.EventTime);
		env.setParallelism(1); // 并行度
		
		// 读取文本的数据流
		DataStream<String> unionStream = env.readTextFile(filePaths[0]); // 初始值
		if(filePaths.length > 1){
			for (int i = 1; i < filePaths.length; i++){
				unionStream = unionStream.union(env.readTextFile(filePaths[i]));
			}
		}
		
		// 数据转换，构造整个数据处理的逻辑，计算出结果并打印出来
		unionStream.map(new MapFunction<String, UserRecord>() {

			@Override
			public UserRecord map(String value) throws Exception {
				// TODO Auto-generated method stub
				return getRecord(value);
			}
		})
		.assignTimestampsAndWatermarks(new Record2TimeStampsExecuter()) // 判断新水印产生时间是否大于上一次水印产生时间，如果大于选择新水印，小于则选择上一次水印
		.filter(new FilterFunction<UserRecord>() {
			
			@Override
			public boolean filter(UserRecord value) throws Exception {
				// TODO Auto-generated method stub
				return value.gender.equals("female");
			}
		})
		.keyBy(new UserRecordSelector()) // 将<<name,gender>,shoppingTime>
		.window(TumblingEventTimeWindows.of(Time.milliseconds(windowTime)))
		.reduce(new ReduceFunction<UserRecord>() {
			
			@Override
			public UserRecord reduce(UserRecord value1, UserRecord value2) throws Exception {
				// TODO Auto-generated method stub
				value1.shoppingTime += value2.shoppingTime;
				return value1;
			}
		})
		.filter(new FilterFunction<UserRecord>() {

			@Override
			public boolean filter(UserRecord value) throws Exception {
				// TODO Auto-generated method stub
				return value.shoppingTime > 120;
			}
			
		})
		.print()
		;
		
		env.execute("FlinkStreamJavaExample");
		
	}
	
	// 构建KeyBy的关键字作为分组依据
	public static class UserRecordSelector implements KeySelector<UserRecord, Tuple2<String, String>>{

		@Override
		public Tuple2<String, String> getKey(UserRecord value) throws Exception {
			// TODO Auto-generated method stub
			return Tuple2.of(value.name, value.gender);
		}
		
	}
	
	// 定义水印方法
	public static class Record2TimeStampsExecuter implements AssignerWithPunctuatedWatermarks<UserRecord>{

		@Override
		public long extractTimestamp(UserRecord arg0, long arg1) {
			// TODO Auto-generated method stub
			return System.currentTimeMillis();
		}

		@Override
		public Watermark checkAndGetNextWatermark(UserRecord element, long extractedTimestamp) {
			// TODO Auto-generated method stub
			return new Watermark(extractedTimestamp - 1); 
		}
		
	}
	
	// 解析文本数据，构造UserRecord数据结构
	public static UserRecord getRecord(String line){
		String[] elems = line.split(",");
		assert elems.length == 3;
		return new UserRecord(elems[0], elems[1], Integer.parseInt(elems[2]));
	}
	
	// 定义UserRecord数据结构的定义，并重写toString函数
	public static class UserRecord{
		public String name;
		public String gender;
		public int shoppingTime;
		public UserRecord(){};
		public UserRecord(String n, String g, int s){
			this.name = n;
			this.gender = g;
			this.shoppingTime = s;
		}
		
		public String toString(){
			return "name: " + name + ", gender: " + gender + ", shoppingTime: " + shoppingTime; 
		}
	}

}