Я пытаюсь написать пример использования Spring Data и подключить к Кассандре (тема http://docs.spring.io/spring-data/cassandra/docs/1.0.2.RELEASE/reference/html/cassandra.core.html)java.lang.String не может быть приведен к main.java.example.Person
Классы:
public class CassandraApp {
private static final Logger LOG = LoggerFactory.getLogger(CassandraApp.class);
private static Cluster cluster;
private static Session session;
public static void main(String[] args) {
try {
cluster = Cluster.builder().addContactPoints(InetAddress.getLocalHost()).build();
session = cluster.connect("mykeyspace");
CassandraOperations cassandraOps = new CassandraTemplate(session);
cassandraOps.insert(new Person("1234567890", "David", 40));
Select s = QueryBuilder.select().from("person");
s.where(QueryBuilder.eq("id", "1234567890"));
LOG.info(cassandraOps.queryForObject(s, Person.class).getId());
cassandraOps.truncate("person");
} catch (UnknownHostException e) {
e.printStackTrace();
}
}
}
@Table
public class Person {
@PrimaryKey
private String id;
private String name;
private int age;
public Person(String id, String name, int age) {
this.id = id;
this.name = name;
this.age = age;
}
public String getId() {
return this.id;
}
public String getName() {
return name;
}
public int getAge() {
return age;
}
@Override
public String toString() {
return "Person [id=" + id + ", name=" + name + ", age=" + age + "]";
}
}
И я получаю это исключение:
log4j:WARN No appenders could be found for logger (com.datastax.driver.core.Cluster). log4j:WARN Please initialize the log4j system properly. log4j:WARN See http://logging.apache.org/log4j/1.2/faq.html#noconfig for more info. Exception in thread "main" java.lang.ClassCastException: java.lang.String cannot be cast to main.java.example2.Person at main.java.example2.CassandraApp.main(CassandraApp.java:40) at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) at java.lang.reflect.Method.invoke(Method.java:498) at com.intellij.rt.execution.application.AppMain.main(AppMain.java:147)
cassandraOps.queryForObject(s, Person.class)
возвращает значение String
, но мне нужно, чтобы получить класс.
посмотреть здесь https://github.com/lemire/externalsortinginjava –