如何将cassandra行转换为我的java类？

Question

 Here is [a Link](http://stackoverflow.com/questions/32448987/how-to-retrieve-a-very-big-cassandra-table-and-delete-some-unuse-data-from-it#comment52844466_32464409) of my question before.
 After I get  the cassandra data row by row in my program, I'm confused by the convert between cassandra row to java class. In java class the table of cassandra is convert to a ResultSet class,when I iterator it and get the row data,it returns a NPE. In fact,I can see the Object (or the data) while  debuging the program. Here is My Iterator Code:


        ResultSet rs=CassandraTools.getInstance().execute(cql);
        Iterator<Row> iterator = rs.iterator();
        while (iterator.hasNext()) {
            Row row = iterator.next();
            row.getString()  ---->return NPE

CassandraTools课程是：

public class CassandraTools {

private static CassandraTools instance;

private CassandraTools() {
}

public static synchronized CassandraTools getInstance() {
    if (instance == null) {
        instance = new CassandraTools();
        instance.init();
    }
    return instance;
}

Cluster cluster;
Session session;

public void init() {
    if (cluster == null) {
        cluster = new Cluster.Builder().addContactPoint("10.16.34.96")
                .build();
        if (session == null) {
            session = cluster.connect("uc_passport");
        }
    }
}

public ResultSet execute(String cql) {
    ResultSet rs = session.execute(cql);
    // rs.forEach(n -> {
    // System.out.println(n);
    // });
    return rs;

}

}

那我怎么能把行中的数据转换成一个java类？我已经读过spring数据cassandra的API中的convert类，但是对我来说它很复杂。谁可以帮忙？