J2EE学习笔记——Hibernate HQL查询

新建一个 java project    .

1、加入 hibernate  支持：

2、选择hibernate  3.3

3、建立hibernate.cfg.xml文件

4、 不选择数据库选项

5、建立 sessionfactory

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项目总体结构：

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    建立 Student.java   

package xuyan.com.vo;import javax.persistence.Entity;import javax.persistence.GeneratedValue;import javax.persistence.Id;@Entitypublic class Student {@Id@GeneratedValue    public int getID() {return ID;}public void setID(int iD) {ID = iD;}public String getName() {return name;}public void setName(String name) {this.name = name;}private int ID;       private String name;       private int age;public int getAge() {return age;}public void setAge(int age) {this.age = age;}}

hibernate.cfg.xml  文件：

<?xml version='1.0' encoding='UTF-8'?><!DOCTYPE hibernate-configuration PUBLIC          "-//Hibernate/Hibernate Configuration DTD 3.0//EN"          "http://hibernate.sourceforge.net/hibernate-configuration-3.0.dtd"><!-- Generated by MyEclipse Hibernate Tools.                   --><hibernate-configuration><session-factory name="mysql"><property name="hibernate.connection.driver_class">com.microsoft.sqlserver.jdbc.SQLServerDriver</property><property name="hibernate.connection.url">jdbc:sqlserver://localhost:1433;DatabaseName=HibernateHQL</property><property name="hibernate.connection.username">sa</property><property name="hibernate.connection.password">1234</property><property name="hibernate.dialect">org.hibernate.dialect.SQLServerDialect</property><property name="hibernate.show_sql">true</property><property name="hibernate.hbm2ddl.auto">update</property><property name="current_session_context_class">thread</property><mapping class="xuyan.com.vo.Student" /></session-factory></hibernate-configuration>

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建立一个测试方法：

     TestStudent.java

package xuyan.com.vo;import java.util.List;import org.hibernate.Query;import org.hibernate.Session;import org.hibernate.SessionFactory;import org.hibernate.Transaction;import org.hibernate.cfg.AnnotationConfiguration;import org.hibernate.tool.hbm2ddl.SchemaExport;import junit.framework.TestCase;public class TestStudent extends TestCase{   private static SessionFactory sessionFactory;@Overrideprotected void setUp() throws Exception { sessionFactory=new AnnotationConfiguration().configure().buildSessionFactory();}@Overrideprotected void tearDown() throws Exception {sessionFactory.close();}    public void testSchemaExport(){SchemaExport sch=new SchemaExport( new AnnotationConfiguration().configure());sch.create(true, true);}public void testSave(){Session  session=sessionFactory.getCurrentSession();Transaction tx=session.beginTransaction();try {   Student  student=new Student();   //student.setID(1);   student.setName("sky99");   student.setAge(28);   session.save(student);   tx.commit();} catch (Exception e) {tx.rollback();e.printStackTrace();}}public void testQuery(){Session  session=sessionFactory.getCurrentSession();Transaction tx=session.beginTransaction();try {   String hql="from Student";   Query query=session.createQuery(hql);      List<Student>  list = query.list();      for(Student s :list)   {   System.out.println(s.getID()+"=="+s.getName());   }   tx.commit();} catch (Exception e) {tx.rollback();e.printStackTrace();}}public void testQueryOne(){Session  session=sessionFactory.getCurrentSession();Transaction tx=session.beginTransaction();try {   String hql="from Student where age>:age ";   Query query=session.createQuery(hql);   query.setParameter("age", 20);   List<Student>  list = query.list();      for(Student s :list)   {   System.out.println(s.getID()+"=="+s.getName());   }   tx.commit();} catch (Exception e) {tx.rollback();e.printStackTrace();}}public void testSelectQuery(){Session  session=sessionFactory.getCurrentSession();Transaction tx=session.beginTransaction();try {   String hql=" select ID,name,age from Student  ";   Query query=session.createQuery(hql);    List list = query.list();     for(int i=0;i<list.size();i++)  {  Object[] obj=(Object[]) list.get(i);  System.out.println("ID："+obj[0]+"名字:"+obj[1]+"年龄："+obj[2]);  }   tx.commit();} catch (Exception e) {tx.rollback();e.printStackTrace();}}}

可以在测试方法中  进行测试

注意：

1、 String hql="from Student";   语句中       数据库表名   区分大小写     

2、 String hql=" select ID,name,age from Student  ";       当hql  语句为select   中    

    必须用

       for(int i=0;i<list.size();i++)
              {
                  Object[] obj=(Object[]) list.get(i);
                  System.out.println("ID："+obj[0]+"名字:"+obj[1]+"年龄："+obj[2]);
              }

             方法进行输出

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