使用Spark / Cassandra连接器从Cassandra数据库检索包含null的数据时出错

Question

我想在java中使用Cassandra / spark Connector从Cassandra中检索数据。表中的某些值为null。我用

JavaRDD<String> rdd = javaFunctions(sc).cassandraTable("test", "Sportman", Sportman.class)
            .map(new org.apache.spark.api.java.function.Function<Sportman, String>() {
                @Override
                public String call(Sportman person) throws Exception {
                    return person.toString();
                }
            });

尝试运行程序时出现此错误。

TypeConversionException：无法将表test.Sportman完成的列转换为java.lang.Boolean：null

我定义Sportman类是这样的：

public static class Sportman implements Serializable{
    private UUID rowid;
    private Boolean accomplished;


    public Sportman(){}

    public UUID getRowid() {
        return rowid;
    }

    public void setRowid(UUID rowid) {
        this.rowid = rowid;
    }

    public Boolean getAccomplished() {
        return accomplished;
    }

    public void setAccomplished(Boolean accomplished) {

            this.accomplished = accomplished;

    }

我不知道如何更改get方法来修复此错误。任何帮助将不胜感激。