xxx in ‘Anonymous class derived from xxx clashes with ‘call(T)‘ in xxx attempting to use incompati

完整报错如下:

'call(Tuple2<Long, Row>)' in 'Anonymous class derived from org.apache.spark.api.java.function.PairFlatMapFunction'

clashes with 'call(T)' in 'org.apache.spark.api.java.function.PairFlatMapFunction';

attempting to use incompatible return type

点击PairFlatMapFunction源码:

@FunctionalInterface
public interface PairFlatMapFunction<T, K, V> extends Serializable {Iterator<Tuple2<K, V>> call(T t) throws Exception;
}

发现要求返回iterator

原因：

两处不一致:

①return处与public后面的类型不一致。

②Tuple2<String,Row>应该改成Tuple2<String,Row>

解决方案如下:

    private static PairFlatMapFunction<Tuple2<Long,Row>, String, Row>func7= new PairFlatMapFunction<Tuple2<Long,Row>, String, Row>() {private static final long serialVersionUID = 1L;public Iterable<Tuple2<String, Row>> call(Tuple2<Long, Row> tuple) throws Exception 
{Random random = new Random();List<Tuple2<String, Row>> list = new ArrayList<Tuple2<String, Row>>();for(int i = 0; i < 100; i++) {list.add(new Tuple2<String, Row>(i + "_" + tuple._1, tuple._2));}return list;}
};

改成:

private static  PairFlatMapFunction<Tuple2<String,Row>, String, Row>  func7 = new PairFlatMapFunction<Tuple2<String,Row>, String, Row>(){private static final long serialVersionUID = 1L;
//    @Overridepublic Iterator<Tuple2<String, Row>> call(Tuple2<String, Row> tuple) throws Exception
{Random random = new Random();List<Tuple2<String, Row>> list = new ArrayList<Tuple2<String, Row>>();for(int i = 0; i < 100; i++){list.add(new Tuple2<String, Row>(i + "_" + tuple._1, tuple._2));}return list.iterator();}};