努力學習Hibernate的命名查詢,我想學習如何執行NamedQuries
但evertime我得到Exception in thread "main" org.hibernate.MappingException: Named query not known
。請幫我在這裏MappingException:不知道
錯誤(只有消息,不顯示完整堆)
Exception in thread "main" org.hibernate.MappingException: Named query not known: hibernate_tut_emp.Employee.FindCountOfNames
at org.hibernate.internal.AbstractSessionImpl.getNamedQuery(AbstractSessionImpl.java:177)
at org.hibernate.internal.SessionImpl.getNamedQuery(SessionImpl.java:1372)
at hibernate_tut_emp.MyOps.main(MyOps.java:20)
Employee.java
package hibernate_tut_emp;
import java.io.Serializable;
import javax.persistence.Column;
import javax.persistence.Entity;
import javax.persistence.GeneratedValue;
import javax.persistence.Id;
import javax.persistence.Table;
import javax.persistence.NamedQueries;
import javax.persistence.NamedQuery;
@Entity
@Table(name="Hib1")
@NamedQueries({
@NamedQuery(name="GetDetailsByName" , query="select * from hib1 h where h.name=:name"),
@NamedQuery(name="FindCountOfNames", query="select count(1) as cnt from hib1 h where h.name=:name")
})
public class Employee {
private int id;
private String name;
@Id
@Column(name="id")
public int getId() {
return id;
}
public void setId(int id) {
this.id = id;
}
@Column(name="name")
public String getName() {
return name;
}
public void setName(String empName) {
this.name = empName;
}
}
MyOps.java
package hibernate_tut_emp;
import java.util.Scanner;
import org.hibernate.Query;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
public class MyOps {
public static void main(String[] args) {
Scanner scnr = new Scanner(System.in);
System.out.print("Enter a name : ");
String name = scnr.next();
SessionFactory ses = HibernateUtil.getSessionFactory();
Session session = ses.openSession();
Query query = session.getNamedQuery("hibernate_tut_emp.Employee.FindCountOfNames");
query.setString("name", name);
int count = ((Integer)query.iterate().next()).intValue();
System.out.println("count : "+count);
}
}
employee.hbm.xml
<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
"-//Hibernate/Hibernate Mapping DTD 3.0//EN"
"http://hibernate.sourceforge.net/hibernate-mapping-3.0.dtd">
<hibernate-mapping>
<class name="hibernate_tut_emp.Employee" table="hib1">
<id name="id" type="int" column="id">
<generator class="native" />
</id>
<property name="name" type="string" column="name" />
</class>
</hibernate-mapping>
的hibernate.cfg.xml
<?xml version='1.0' encoding='utf-8'?>
<!DOCTYPE hibernate-configuration PUBLIC
"-//Hibernate/Hibernate Configuration DTD//EN"
"http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd">
<hibernate-configuration>
<session-factory>
<!-- Database connection settings -->
<property name="connection.driver_class">com.mysql.jdbc.Driver</property>
<property name="connection.url">jdbc:mysql://localhost:3306/hibernate</property>
<property name="connection.username">root</property>
<property name="connection.password">mayank</property>
<!-- JDBC connection pool (use the built-in) -->
<property name="connection.pool_size">1</property>
<!-- SQL dialect -->
<property name="dialect">org.hibernate.dialect.MySQLDialect</property>
<!-- Enable Hibernate's automatic session context management -->
<property name="current_session_context_class">thread</property>
<!-- Disable the second-level cache -->
<property name="cache.provider_class">org.hibernate.cache.NoCacheProvider</property>
<!-- Echo all executed SQL to stdout -->
<property name="show_sql">true</property>
<!-- Drop and re-create the database schema on startup -->
<property name="hbm2ddl.auto">update</property>
<mapping class="hibernate_tut_emp.Employee" />
<mapping resource="employee.hbm.xml"/>
</session-factory>
</hibernate-configuration>
我GOOGLE了一切可能但我認爲我忽視了一些基本的東西。任何跡象表明,在正確的方向表示讚賞! :)
有一件事我考慮的是,如果我在類文件NamedQueries
定義,我不需要提到它在XML file.Please糾正我,如果我錯了!
你爲什麼要同時使用一個類及其註釋和xml文件,todefine同一類的映射?只需使用其中的一個(最好是類和它的註釋)。還要注意這兩個查詢都不正確。 '*'是SQL,而不是HQL。 HQL使用實體名稱(即類名稱),而不是表名。而第二個查詢中未定義「h」。 – 2014-09-28 10:39:13
@JBNizet:好的......你的意思是說,如果我在'Employee.java'中有'annotations',我不需要'employee.hbm.xml'? – NoobEditor 2014-09-28 10:41:08
不,你不需要它。當註釋不存在時,XML映射非常有用(Java 4,我們在Java 8)。 – 2014-09-28 10:42:13