目的：三种基本转换算子map、flatMap、filter
环境：jdk8 工具：idea2019.3

创建maven项目

引入jar包

  1.         <dependency>
  2.             <groupId>org.apache.flink</groupId>
  3.             <artifactId>flink-java</artifactId>
  4.             <version>1.10.1</version>
  5.         </dependency>
  6.         <dependency>
  7.             <groupId>org.apache.flink</groupId>
  8.             <artifactId>flink-streaming-java_2.12</artifactId>
  9.             <version>1.10.1</version>
  10.         </dependency>

代码演示

  1.         StreamExecutionEnvironment env = StreamExecutionEnvironment.getExecutionEnvironment();
  3.         DataStream<String> dataStream = env.readTextFile("绝对路径");
  5.         //对值进行处理后可以用不同格式返回
  6.         DataStream<Integer> integerDataStream = dataStream.map(new MapFunction<String, Integer>() {
  7.             public Integer map(String value) throws Exception {
  8.                 return value.length();
  9.             }
  10.         });
  11.         //单个值的输入后可以进行多值输出
  12.         DataStream<String> flatMap = dataStream.flatMap(new FlatMapFunction<String, String>() {
  13.             public void flatMap(String value, Collector<String> out) throws Exception {
  14.                 String[] fields=value.split(" ");
  15.                 for (String field:fields){
  16.                     out.collect(field);
  17.                 }
  18.             }
  19.         });
  20.        //进行过滤元素
  21.         DataStream<String> stringDataStream=dataStream.filter(new FilterFunction<String>() {
  22.             public boolean filter(String value) throws Exception {
  23.                 return value.contains("test");
  24.             }
  25.         });
  28.         stringDataStream.print("filter");
  29.         flatMap.print("flatMap");
  30.         integerDataStream.print("map");

基本转换算子.rar

结果

  1. SLF4J: Failed to load class "org.slf4j.impl.StaticLoggerBinder".
  2. SLF4J: Defaulting to no-operation (NOP) logger implementation
  3. SLF4J: See http://www.slf4j.org/codes.html#StaticLoggerBinder for further details.
  4. map:3> 10
  5. flatMap:3> hello
  6. flatMap:3> test
  7. filter:3> hello test
  8. map:4> 10
  9. flatMap:4> hello
  10. flatMap:4> java
  11. map:2> 10
  12. flatMap:2> hello
  13. flatMap:2> word