Java Can';t使用Hibernate从表中添加和删除数据
获取数据非常有效,但我无法从表中添加和删除数据。我能做什么 TaskDAO类:Java Can';t使用Hibernate从表中添加和删除数据,java,mysql,hibernate,jpa,orm,Java,Mysql,Hibernate,Jpa,Orm,获取数据非常有效,但我无法从表中添加和删除数据。我能做什么 TaskDAO类: DBServiceclass: 但我在数据库中看不到任何变化 表格: 我几乎可以肯定,这个问题是由于您不以任何方式管理您的交易。关于查询,您将获得数据,但要在数据库上反映DML操作,您需要一个事务: public long addTask(String name) { Session session = sessionFactory.openSession(); Transaction
DBService
class:
但我在数据库中看不到任何变化
表格:
我几乎可以肯定,这个问题是由于您不以任何方式管理您的交易。关于查询,您将获得数据,但要在数据库上反映DML操作,您需要一个事务:
public long addTask(String name) {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
TaskDAO dao = new TaskDAO(session);
long id = dao.insert(name);
tx.commit();
session.close()
return id;
}
public void deleteTask(long id) throws DBException {
try {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
TaskDAO dao = new TaskDAO(session);
dao.delete(id);
tx.commit();
session.close();
} catch (HibernateException e) {
throw new DBException(e);
}
}
另外,在手动管理会话时,不要忘记始终关闭会话。您是如何设置事务管理的?
@Entity
@Table(name="task")
public class TaskDataSet {
@Id
@Column(name = "id")
@GeneratedValue(strategy = GenerationType.AUTO)
private long id;
@Column(name = "name", unique = true, updatable = false, nullable = false)
private String name;
@Column(name = "done")
private boolean done;
public TaskDataSet() {}
public TaskDataSet(String name) {
this.name = name;
done = false;
}
public long getId() {
return id;
}
public String getName() {
return name;
}
public boolean isDone() {
return done;
}
public void setId(int id) {
this.id = id;
}
public void setName(String name) {
this.name = name;
}
public void setDone(boolean done) {
this.done = done;
}
}
public class DBService {
private static final String hibernate_show_sql = "true";
private static final String hibernate_hbm2ddl_auto = "update";
private SessionFactory sessionFactory;
public DBService() {
Configuration configuration = getMySqlConfiguration();
this.sessionFactory = configuration.configure().buildSessionFactory();
}
private Configuration getMySqlConfiguration() {
Configuration configuration = new Configuration();
configuration.addAnnotatedClass(TaskDataSet.class);
configuration.setProperty("hibernate.dialect", "org.hibernate.dialect.MySQLDialect");
configuration.setProperty("hibernate.connection.driver_class", "com.mysql.jdbc.Driver");
configuration.setProperty("hibernate.connection.url", "jdbc:mysql://localhost:3306/test");
configuration.setProperty("hibernate.connection.username", "root");
configuration.setProperty("hibernate.connection.password", "root");
configuration.setProperty("hibernate.show_sql", hibernate_show_sql);
configuration.setProperty("hibernate.hbm2ddl.auto", hibernate_hbm2ddl_auto);
return configuration;
}
public TaskDataSet getTask(long id) throws DBException {
try {
Session session = sessionFactory.openSession();
TaskDAO dao = new TaskDAO(session);
TaskDataSet dataSet = dao.get(id);
session.close();
return dataSet;
} catch (HibernateException e) {
throw new DBException(e);
}
}
public List<TaskDataSet> getAllTasks() throws DBException {
try {
Session session = sessionFactory.openSession();
TaskDAO dao = new TaskDAO(session);
List<TaskDataSet> tasks = dao.getAll();
return tasks;
} catch (HibernateException e) {
throw new DBException(e);
}
}
public long addTask(String name) {
Session session = sessionFactory.openSession();
TaskDAO dao = new TaskDAO(session);
return dao.insert(name);
}
public void deleteTask(long id) throws DBException {
try {
Session session = sessionFactory.openSession();
TaskDAO dao = new TaskDAO(session);
dao.delete(id);
} catch (HibernateException e) {
throw new DBException(e);
}
}
public static void main(String[] args) throws DBException {
DBService dbService = new DBService();
dbService.addTask("Test3");
for (TaskDataSet task : dbService.getAllTasks()) {
System.out.println(task.getId());
System.out.println(task.getName());
System.out.println(task.isDone());
System.out.println("---------------------------------");
}
dbService.deleteTask(1);
for (TaskDataSet task : dbService.getAllTasks()) {
System.out.println(task.getId());
System.out.println(task.getName());
System.out.println(task.isDone());
System.out.println("---------------------------------");
}
}
}
14:20:29.738 [main] DEBUG org.hibernate.stat.internal.StatisticsInitiator - Statistics initialized [enabled=false]
14:20:29.748 [main] DEBUG org.hibernate.SQL - select next_val as id_val from hibernate_sequence for update
Hibernate: select next_val as id_val from hibernate_sequence for update
14:20:29.758 [main] DEBUG org.hibernate.SQL - update hibernate_sequence set next_val= ? where next_val=?
Hibernate: update hibernate_sequence set next_val= ? where next_val=?
14:20:29.789 [main] DEBUG org.hibernate.event.internal.AbstractSaveEventListener - Generated identifier: 12, using strategy: org.hibernate.id.enhanced.SequenceStyleGenerator
CREATE TABLE IF NOT EXISTS task (
id SERIAL NOT NULL,
name VARCHAR(150) NOT NULL,
done BOOLEAN NOT NULL,
PRIMARY KEY (id)
);
public long addTask(String name) {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
TaskDAO dao = new TaskDAO(session);
long id = dao.insert(name);
tx.commit();
session.close()
return id;
}
public void deleteTask(long id) throws DBException {
try {
Session session = sessionFactory.openSession();
Transaction tx = session.beginTransaction();
TaskDAO dao = new TaskDAO(session);
dao.delete(id);
tx.commit();
session.close();
} catch (HibernateException e) {
throw new DBException(e);
}
}