打開Hibernate的Session的源碼，我們可以看到有一個getNamedQuery(String name);的方法，如下：

/*** Obtain an instance of <tt>Query</tt> for a named query string defined in the* mapping file.** @param queryName the name of a query defined externally* @return Query* @throws HibernateException*/public Query getNamedQuery(String queryName) throws HibernateException;

?

這個方法就是可以執行定義在Hibernate實體類映射文件中的HQL或Sql語句。

具體做法下面我一一講解，首先測試在映射文件中定義HQL語句。

我在User實體類的映射文件中定義了一個name為getUserByName的HQL查詢語句，代碼如下：

<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""D:\tools\hibernate\dtd\hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.xigua.domain"><class name="User"><id name="id"><generator class="native"/></id><property name="name"/><property name="birthday"/></class><!-- 定義一個查詢，名稱為getUserByName --><query name="getUserByName"><![CDATA[from User where name = :name]]></query> </hibernate-mapping>

?

然后編寫測試類使用Session中的getNamedQuery(String name)方法進行測試，代碼如下：

package com.xigua.test;import java.util.Date; import java.util.List;import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.Transaction;import com.xigua.domain.User; import com.xigua.utils.HibernateUtil;public class Test9 {public static void main(String[] args) {addUser();String name = "xigua";List<User> list = namedQuery(name);if(list != null && !list.isEmpty()) {for(User user : list) {System.out.println(user.getId() + ", " + user.getName() + ", " + user.getBirthday());}}}public static void addUser() {Session session = null;Transaction tx = null;try{session = HibernateUtil.getSession();tx = session.beginTransaction();User user = new User();user.setName("xigua");user.setBirthday(new Date());session.save(user);user = new User();user.setName("donggua");user.setBirthday(new Date());session.save(user);tx.commit();} catch(Exception e) {if(tx != null) {tx.rollback();}} finally {if(session != null) {session.close();}}}public static List<User> namedQuery(String name) {Session session = null;try{session = HibernateUtil.getSession();Query query = session.getNamedQuery("getUserByName");query.setParameter("name", name);return query.list();}catch(Exception e) {e.printStackTrace();} finally {if(session != null) {session.close();}}return null;}}

?注意紅色部分代碼。

?

在映射文件中除了可以定義HQL語句，也還是可以定義Sql語句的。

前面的User實體類的映射文件修改如下：

<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""D:\tools\hibernate\dtd\hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.xigua.domain"><class name="User"><id name="id"><generator class="native"/></id><property name="name"/><property name="birthday"/></class><!-- 定義一個查詢，名稱為getUserByName <query name="getUserByName"><![CDATA[from User where name = :name]]></query>--><sql-query name="getUserByName"><![CDATA[select id, name from user where name = :name]]></sql-query> </hibernate-mapping>

?

測試代碼如下：

package com.xigua.test;import java.util.Date;import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.Transaction;import com.xigua.domain.User; import com.xigua.utils.HibernateUtil;public class Test10 {public static void main(String args[]) {addUser();String name = "xigua";User user = namedSqlQuery(name);if(user != null) {System.out.println(user.getId() + ", " + user.getName());}}public static void addUser() {Session session = null;Transaction tx = null;try{session = HibernateUtil.getSession();tx = session.beginTransaction();User user = new User();user.setName("xigua");user.setBirthday(new Date());session.save(user);user = new User();user.setName("donggua");user.setBirthday(new Date());session.save(user);tx.commit();} catch(Exception e) {if(tx != null) {tx.rollback();}} finally {if(session != null) {session.close();}}}public static User namedSqlQuery(String name) {Session session = null;try{session = HibernateUtil.getSession();Query query = session.getNamedQuery("getUserByName");query.setParameter("name", name);Object[] obj = (Object[]) query.uniqueResult();if(obj != null) {User user = new User();user.setId(Long.valueOf(obj[0].toString()));user.setName(obj[1].toString());return user;}}catch(Exception e) {e.printStackTrace();} finally {if(session != null) {session.close();}}return null;}}

?

映射文件中還有些其它的配置，暫時還沒具體搞懂，比如下面紅色的代碼：

<sql-query name="getUserByName"><![CDATA[select id, name from user where name = :name]]><query-param name="name" type="string"/><return></return><return-join alias="" property=""></return-join><return-scalar column=""/><synchronize table=""/></sql-query>

?

?

還有一點像說明的是<query>跟<sql-query>的配置是可以放到<class>節點里面的。

我現在是放在<class>節點外面，表示全局可用，這里需要注意不要跟其它映射文件中定義的<query>或<sql-query>同名。

如果將<query>或<sql-query>放在<class>節點里面，在java代碼中使用的時候需要將package名跟class名都寫上，具體見下面配置的映射文件代碼跟測試代碼。

映射文件代碼：

<?xml version="1.0"?> <!DOCTYPE hibernate-mapping PUBLIC "-//Hibernate/Hibernate Mapping DTD 3.0//EN""D:\tools\hibernate\dtd\hibernate-mapping-3.0.dtd"> <hibernate-mapping package="com.xigua.domain"><class name="User"><id name="id"><generator class="native"/></id><property name="name"/><property name="birthday"/><!-- 定義一個查詢，名稱為getUserByName (這里將<query>放到<class>節點里面來)--> <query name="getUserByName"><![CDATA[from User where name = :name]]></query></class></hibernate-mapping>

?java測試代碼（注意下圖紅色部分字符串）

package com.xigua.test;import java.util.Date; import java.util.List;import org.hibernate.Query; import org.hibernate.Session; import org.hibernate.Transaction;import com.xigua.domain.User; import com.xigua.utils.HibernateUtil;public class Test9 {public static void main(String[] args) {addUser();String name = "xigua";List<User> list = namedQuery(name);if(list != null && !list.isEmpty()) {for(User user : list) {System.out.println(user.getId() + ", " + user.getName() + ", " + user.getBirthday());}}}public static void addUser() {Session session = null;Transaction tx = null;try{session = HibernateUtil.getSession();tx = session.beginTransaction();User user = new User();user.setName("xigua");user.setBirthday(new Date());session.save(user);user = new User();user.setName("donggua");user.setBirthday(new Date());session.save(user);tx.commit();} catch(Exception e) {if(tx != null) {tx.rollback();}} finally {if(session != null) {session.close();}}}public static List<User> namedQuery(String name) {Session session = null;try{session = HibernateUtil.getSession();Query query = session.getNamedQuery("com.xigua.domain.User.getUserByName");query.setParameter("name", name);return query.list();}catch(Exception e) {e.printStackTrace();} finally {if(session != null) {session.close();}}return null;}}

轉載于:https://www.cnblogs.com/limengtr/p/4074594.html

總結

以上是生活随笔為你收集整理的Hibernate的命名查询（NamedQuery）的全部內容，希望文章能夠幫你解決所遇到的問題。

如果覺得生活随笔網站內容還不錯，歡迎將生活随笔推薦給好友。