使用flink 提供的ParameterTool 获取参数

flink 提供的ParameterTool 获取参数

代码

package com.it.flink.wordcount;

import org.apache.flink.api.common.functions.FlatMapFunction;
import org.apache.flink.api.java.tuple.Tuple2;
import org.apache.flink.api.java.utils.ParameterTool;
import org.apache.flink.streaming.api.datastream.DataStreamSource;
import org.apache.flink.streaming.api.datastream.SingleOutputStreamOperator;
import org.apache.flink.streaming.api.environment.StreamExecutionEnvironment;
import org.apache.flink.util.Collector;


/**
 * 代码主要演示如何获取args传递的参数
 */
public class StreamWordCountGetParam {

    public static void main(String[] args) throws Exception {

        String host = "";
        int port = 0;
        try {
            //flink 提供的ParameterTool 获取参数
            ParameterTool tool = ParameterTool.fromArgs(args);

            host = tool.get("host");
            port = Integer.parseInt(tool.get("prot"));
        }catch (Exception e){
            e.printStackTrace();
            port = 9999;
            host = "t1";
            System.out.println("未设置参数使用默认值");

        }



        //创建一个 flink stream 程序的执行环境
        StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();

        //使用StreamExecutionEnvironment 创建DataStream
        DataStreamSource<String> lines = env.socketTextStream(host, port);

        //调用DataStream上的方法 Transformation
        SingleOutputStreamOperator<Tuple2<String,Integer>> wordAndOne = lines.flatMap(new FlatMapFunction<String, Tuple2<String,Integer>>() {
            @Override
            public void flatMap(String s, Collector<Tuple2<String,Integer>> collector) throws Exception {
                //切分
                String[] split = s.split(" ");
                for (String s1 : split) {
                    //输出前 组成元祖再返回
                    Tuple2<String, Integer> of = Tuple2.of(s1, 1);
                    collector.collect(of);
                }
            }
        });

        //将单词和一进行组合 ctrl+ i 或者tab 补全

        //按单词分组 按value进行聚合  keyBy(0) 元祖中的第一个元素 sum(1)元祖中的第二个元素
        SingleOutputStreamOperator<Tuple2<String, Integer>> keyBy = wordAndOne.keyBy(0).sum(1);

        //调用sink (sink 必须调用)
        //此处sink 是 print
        keyBy.print();

        //启动程序 给个JobName 启动有异常不要捕获要跑出去
        env.execute("StreamWordCount");

        /**
         * 7> (flink,1)
         * 7> (flink,2)
         * 7> (flink,3)
         */
    }
}

在IDEA中如传递参数

看源码

Keys have to start with ‘-’ or ‘–’

		if (args[i].startsWith("--")) {
			key = args[i].substring(2);
		} else if (args[i].startsWith("-")) {

/**
	 * Returns {@link ParameterTool} for the given arguments. The arguments are keys followed by values.
	 * Keys have to start with '-' or '--'
	 *
	 * <p><strong>Example arguments:</strong>
	 * --key1 value1 --key2 value2 -key3 value3
	 *
	 * @param args Input array arguments
	 * @return A {@link ParameterTool}
	 */
	public static ParameterTool fromArgs(String[] args) {
		final Map<String, String> map = new HashMap<>(args.length / 2);

		int i = 0;
		while (i < args.length) {
			final String key;

			if (args[i].startsWith("--")) {
				key = args[i].substring(2);
			} else if (args[i].startsWith("-")) {
				key = args[i].substring(1);
			} else {
				throw new IllegalArgumentException(
					String.format("Error parsing arguments '%s' on '%s'. Please prefix keys with -- or -.",
						Arrays.toString(args), args[i]));
			}

			if (key.isEmpty()) {
				throw new IllegalArgumentException(
					"The input " + Arrays.toString(args) + " contains an empty argument");
			}

			i += 1; // try to find the value

			if (i >= args.length) {
				map.put(key, NO_VALUE_KEY);
			} else if (NumberUtils.isNumber(args[i])) {
				map.put(key, args[i]);
				i += 1;
			} else if (args[i].startsWith("--") || args[i].startsWith("-")) {
				// the argument cannot be a negative number because we checked earlier
				// -> the next argument is a parameter name
				map.put(key, NO_VALUE_KEY);
			} else {
				map.put(key, args[i]);
				i += 1;
			}
		}

		return fromMap(map);
	}