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我正在研究一個使用Spring MVC和JPA的Web項目，它使用MAVEN構建。不知怎的，我不知道是否我已經JPA配置做得正確，因爲我得到這個錯誤，而開展網絡爲什麼在實體中拋出的QuerySyntaxException未映射[來自實體]發生在JPA中？
Caused by: org.hibernate.hql.internal.ast.QuerySyntaxException: User is not mapped [from User]
我在MYSQL表以這種方式創建：
mysql> desc users;
+----------+-------------+------+-----+---------+-------+
| Field | Type | Null | Key | Default | Extra |
+----------+-------------+------+-----+---------+-------+
| username | varchar(10) | NO | PRI | | |
| password | varchar(32) | YES | | NULL | |
| enabled | int(11) | YES | | NULL | |
+----------+-------------+------+-----+---------+-------+
3 rows in set (0.00 sec)
我有用戶實體聲明中這樣說：
@Entity
@Table(name="users")
public class User {
@Id
@Column(name="username")
private String username;
@Column(name="password")
private String password;
@Column(name="enabled")
private Integer enabled;
我有這樣的配置datasource.xml：
<bean id="dataSource" class="org.springframework.jdbc.datasource.DriverManagerDataSource">
<property name="driverClassName" value="com.mysql.jdbc.Driver"/>
<property name="url" value="jdbc:mysql://localhost:3306/test"/>
<property name="username" value="root"/>
<property name="password" value="root"/>
</bean>
<bean id="entityManagerFactory" class="org.springframework.orm.jpa.LocalContainerEntityManagerFactoryBean">
<property name="jpaVendorAdapter" ref="jpaVendorAdapter" />
<property name="dataSource" ref="dataSource"/>
<property name="packagesToScan" value="org.huahsin.ProjectA.*" />
</bean>
<bean id="jpaVendorAdapter" class="org.springframework.orm.jpa.vendor.HibernateJpaVendorAdapter">
<property name="databasePlatform" value="org.hibernate.dialect.MySQLInnoDBDialect" />
<property name="showSql" value="true" />
</bean>
這是DAO將如何調用持久性對象：
@Repository
public class UserDao implements IUserDao {
@PersistenceUnit
private EntityManagerFactory emf;
public User findByUsername(String username) {
List<User> l = (List<User>) emf.createEntityManager().createQuery("from User");
...
}
}