flink readcsvfile方法带有pojotypes

Question

我在flink项目中具有以下代码：

public class Test {
    public static void main(String[] args) throws Exception {
        // set up the execution environment
        final ExecutionEnvironment env = ExecutionEnvironment.getExecutionEnvironment();
        DataSet<Event> events =
            env.readCsvFile(args[0]).pojoType(
               Event.class,
               "time",
               "vid",
               "speed",
               "xWay",
               "lane",
               "dir",
               "seg",
               "pos"
            );
        System.out.println("----> " + events.count());
    }
}

这是Event类：

class Event {
    public int time;
    public int vid;
    public int speed;
    public int xWay;
    public int lane;
    public int dir;
    public int seg;
    public int pos;
    public Event() { }
    public Event(int time_in, int vid_in, int speed_in, int xWay_in, int lane_in, int dir_in, int seg_in, int pos_in) {
        this.time = time_in;
        this.vid = vid_in;
        this.speed = speed_in;
        this.xWay = xWay_in;
        this.lane = lane_in;
        this.dir = dir_in;
        this.seg = seg_in;
        this.pos = pos_in;
    }
}

项目编译，但是当我运行它时，有一个错误：

java.lang.ClassCastException: org.apache.flink.api.java.typeutils.GenericTypeInfo cannot be cast to org.apache.flink.api.java.typeutils.PojoTypeInfo

CSV文件的8个整数值在每行中被一个逗号分隔。

文档具有以下示例：

DataSet<Person>> csvInput = env.readCsvFile("hdfs:///the/CSV/file")
                     .pojoType(Person.class, "name", "age", "zipcode");

我不知道Pojo定义是否错了，肯定是错误的。我使用map和readTextFile实现了我想要的东西，但这可能更昂贵。

Answer 1

ClassCastException是一个错误，将很快修复并取代了一个更有意义的例外。Event是GenericType，而不是PojoType。我认为原因可能是Event是成员类，而不是全球可访问类。添加static修饰符应解决问题。