Hibernate3高级特性-使用过滤器

Hibernate3高级特性-使用过滤器

Hibernate版本(hibernate-distribution-3.3.1.GA)

Hibernate3 新增了对某个类或集合使用预定义的过滤器条件 (filter criteria) 的功能。过滤器条件相当于定义一个非常类似于类和各种集合上的"where"属性的约束子句，但是过滤器条件可以带参数。应用程序可以在运行时决定是否启用给定的过滤器，以及使用什么样的参数值。过滤器的用法很像数据库视图，只还过是在应用程序员中确定使用什么样的参数。摘自--

http://docs.jboss.org/hibernate/core/3.6/reference/zh-CN/html/filters.html

一、在Hibernate中使用过滤器遵循以下步骤

Define the filter within the mapping file of the targeted entity (identity the attributes to filter on,and their types)

Apply the filter on the desired class or collection by indicating it with the <class> or <collection-type> tags

After obtaining a session with which to perform your actions,enable the appropriate filter , setting any applicable parameters

二 使用 Hibernate3 过滤器



工程结构图(1)

在下面的两个例子中，不贴出 hibernate.cfg.xml和log4j.xml 两个配置文件的代码

example 1: Customer Class Filter Test

假设通过指定顾客的年龄作为查询条件，获取符合查询条件的顾客

1。Customer类文件，Customer 的属性分别是：年龄和姓名 并且每个Customer均有各自的id号

Customer.java

package com.laoyangx.chapter0;

import java.io.Serializable;

public class Customer implements Serializable {

private static final long serialVersionUID = 9210200371341904932L;
private Integer id; //顾客编号
private Integer age;  //顾客年龄
private String name; //顾客姓名

public Customer() {

}

public Customer(Integer age, String name) {

this.age = age;
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}

}

2。 Hibernate的工具类

HibernateUtil.java

package com.laoyangx.chapter0;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.SessionFactory;
import org.hibernate.cfg.Configuration;

@SuppressWarnings({"rawtypes","unchecked"})
public class HibernateUtil {
private static final SessionFactory sessionFactory;
private static final ThreadLocal localSession = new ThreadLocal();

static {
try{
sessionFactory = new Configuration().configure().buildSessionFactory();
}catch(HibernateException ex){
throw new RuntimeException("sessionFactory ：" + ex.getMessage(), ex);
}
}

public static Session currentSession() throws HibernateException {
Session s = (Session) localSession.get();
if (s == null) {
s = sessionFactory.openSession();
localSession.set(s);
}
return s;
}

public static void closeSession() throws HibernateException {
Session s = (Session) localSession.get();
localSession.set(null);
if (s != null)
s.close();
}
}

3。Customer类的数据库映射文件,在配置文件增加了<filter-def>和<filter>两个元素，过滤条件是：顾客年龄大于25

chapter0_customer.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="com.laoyangx.chapter0.Customer" table="T_chapter0_customers" >
<id name="id" column="customer_id" type="java.lang.Integer">
<generator class="native"/>
</id>
<property name="age" column="customer_age" type="java.lang.Integer" />
<property name="name" column="customer_name" type="java.lang.String" length="25" />
<filter name="creationAgeFilter" condition="customer_age>:asOfAge" />
</class>
<filter-def name="creationAgeFilter">
<filter-param name="asOfAge" type="java.lang.Integer"/>
</filter-def>
</hibernate-mapping>

4。测试
TestFilterDef.java

package com.laoyangx.chapter0;

import java.util.Iterator;
import java.util.List;

import junit.framework.TestCase;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class TestFilterDef extends TestCase {

/**
* 添加顾客
*/
public void addCustomer(){

Session session=HibernateUtil.currentSession();
Transaction transaction=null;

try {
transaction=session.beginTransaction();

for(int i=20;i<30;i++){

session.save(new Customer(i,"customer"+i));
}

transaction.commit();
} catch (HibernateException e) {

if(transaction!=null) transaction.rollback();

e.printStackTrace();
}
finally{
session.close();
}
}

/**
* 通过指定顾客的年龄作为查询条件，获取顾客
*/
public void getCustomerWithAge(){

Session session=HibernateUtil.currentSession();
Transaction transaciton=null;

try {

transaciton=session.beginTransaction();
session.enableFilter("creationAgeFilter").setParameter("asOfAge", new Integer(25)); //顾客年龄大于25

List resultSet=(List)session.createQuery("from Customer").list();
boolean resultNotEmpty=(resultSet!=null)&&resultSet.size()>0;
if(resultNotEmpty){
for(Iterator iter=resultSet.iterator();iter.hasNext();){
Customer customer=(Customer)iter.next();

System.out.println("customer_id-> "+customer.getId()+" customer_name-> "+customer.getName()
+" customer_age-> "+customer.getAge());
}
}

} catch (HibernateException e) {

if(transaciton!=null) transaciton.rollback();

e.printStackTrace();
}
finally{
session.close();
}

}
}

先运行 addCustomer()方法，向数据库中添加测试数据 运行之后，T_chapter0_customers表中的数据显示如下：



随后执行 getCustomerWithAge() 显示结果如下：



example 2: Customer Collection Filter

假设 Customer 与 Order 是一对多的关系 , 每个 Customer可以有多个 Order

1。Customer类文件，Customer 的属性分别是：年龄和姓名 并且每个Customer均有各自的id号。Order类文件 , Order 的属性分别是：日期、是否可见和订单编号。Customer 与 Order 二者之间通过 customer_order_id 进行关联。

Customer.java

package com.laoyangx.chapter0;

import java.io.Serializable;
import java.util.HashSet;
import java.util.Set;

public class Customer implements Serializable {

private static final long serialVersionUID = 9210200371341904932L;
private Integer id;   //顾客编号
private Integer age;  //顾客年龄
private String name;  //顾客姓名
private Set<Order> orders=new HashSet<Order>();

public Customer() {	}

public Customer(Integer age, String name) {

this.age = age;
this.name = name;
}
public Integer getId() {
return id;
}
public void setId(Integer id) {
this.id = id;
}
public Integer getAge() {
return age;
}
public void setAge(Integer age) {
this.age = age;
}
public String getName() {
return name;
}
public void setName(String name) {
this.name = name;
}

public Set<Order> getOrders() {
return orders;
}

public void setOrders(Set<Order> orders) {
this.orders = orders;
}
}

Order.java

package com.laoyangx.chapter0;

import java.io.Serializable;
import java.text.SimpleDateFormat;
import java.util.Date;

public class Order implements Serializable {

private static final long serialVersionUID = 5266816497026247617L;
private Integer id;  //订单编号
private String date; //订单日期
private Boolean visible; //订单状态
private Customer customer; //订单来源

public Order() {}

public Order(Date date, Customer customer,Boolean visible) {

SimpleDateFormat sdf=new SimpleDateFormat("yyyy-MM-dd");
this.date = sdf.format(date);
this.customer = customer;
this.visible=visible;
}

public Integer getId() {
return id;
}

public void setId(Integer id) {
this.id = id;
}

public String getDate() {
return date;
}

public void setDate(String date) {
this.date =date;
}

public Customer getCustomer() {
return customer;
}

public void setCustomer(Customer customer) {
this.customer = customer;
}

public Boolean getVisible() {
return visible;
}

public void setVisible(Boolean visible) {
this.visible = visible;
}

}

2。HibernateUtil工具类

HibbernateUitl.java 和 example1 中的 HibernateUitl.java 一样

3。Customer类的数据库映射文件,在配置文件增加 两个<filter-def>和<filter>，过滤条件是：订单的visible属性为true且顾客年龄大于25

chapter0_customer.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="com.laoyangx.chapter0.Customer" table="T_chapter0_customers" >
<id name="id" column="customer_id" type="java.lang.Integer">
<generator class="native"/>
</id>
<property name="age" column="customer_age" type="java.lang.Integer" />
<property name="name" column="customer_name" type="java.lang.String" length="25" />

<set name="orders" inverse="true" cascade="all">
<key column="customer_order_id" />
<one-to-many class="com.laoyangx.chapter0.Order"/>
<filter name="creationVisibleFilter" condition="order_visible=:asOfVisible" />
</set>
<filter name="creationAgeFilter" condition="customer_age>:asOfAge" />
</class>

<filter-def name="creationAgeFilter">
<filter-param name="asOfAge" type="java.lang.Integer"/>
</filter-def>

<filter-def name="creationVisibleFilter">
<filter-param name="asOfVisible" type="java.lang.Boolean"/>
</filter-def>

</hibernate-mapping>

chapter0_order.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="com.laoyangx.chapter0.Order" table="T_chapter0_orders" >
<id name="id" column="order_id" type="java.lang.Integer">
<generator class="native"/>
</id>
<property name="date" column="order_date" type="java.lang.String" length="10" />
<property name="visible" column="order_visible" type="java.lang.Boolean" />
<many-to-one name="customer" class="com.laoyangx.chapter0.Customer" column="customer_order_id"></many-to-one>
</class>
</hibernate-mapping>

5。测试

TestFilterDef.java

package com.laoyangx.chapter0;

import java.util.Date;
import java.util.Iterator;
import java.util.List;
import java.util.Set;

import junit.framework.TestCase;

import org.hibernate.HibernateException;
import org.hibernate.Session;
import org.hibernate.Transaction;

public class TestFilterDef extends TestCase {

/**
* 添加顾客和订单号，用于测试
*/
public void fillData(){

Session session=HibernateUtil.currentSession();
Transaction transaction=null;

try {
transaction=session.beginTransaction();

for(int i=20;i<30;i++){

Customer customer=new Customer(i,"customer"+i);

boolean visible=(0==i%2)?false:true; //当顾客的年龄为偶数是 visible=false 反之为 true
Order order=new Order(new Date(),customer,visible);

customer.getOrders().add(order);

session.save(customer);
}

transaction.commit();
} catch (HibernateException e) {

if(transaction!=null) transaction.rollback();

e.printStackTrace();
}
finally{
session.close();
}
}

/**
* 通过指定顾客的年龄作为查询条件，获取顾客
*/
public void getCustomerWithAge(){

Session session=HibernateUtil.currentSession();
Transaction transaciton=null;

try {

transaciton=session.beginTransaction();
session.enableFilter("creationVisibleFilter").setParameter("asOfVisible",true);
session.enableFilter("creationAgeFilter").setParameter("asOfAge", new Integer(25));

List resultSet=(List)session.createQuery("from Customer").list();

Boolean resultNotEmpty=(resultSet!=null)&&resultSet.size()>0;
if(resultNotEmpty){

for(Iterator iter=resultSet.iterator();iter.hasNext();) {

Customer customer=(Customer)iter.next();
Set<Order> orders=customer.getOrders();

Boolean orderIsNullOrEmpty=(orders!=null)&&orders.size()>0;
if(orderIsNullOrEmpty){

System.out.println("customer_id-> "+customer.getId()+" customer_name-> "+customer.getName()
+" customer_age-> "+customer.getAge());

for(Iterator<Order> i=orders.iterator();i.hasNext();){
Order order=(Order)i.next();
System.out.println("order_id-> "+order.getId()+" order_date-> "+order.getDate());
}
}
System.out.println("-----------------------------");
}
}

} catch (HibernateException e) {

if(transaciton!=null) transaciton.rollback();

e.printStackTrace();
}
finally{
session.close();
}
}
}

先运行 fillData()方法 ，向数据库中添加测试数据 运行之后 t_chapter0_customers和t_chapter0_orders这两张表中的数据如下：





order_visible 生成的规律是：顾客的年龄为偶数时候 order_visible=false 反之为true

运行 getCustomerWithAge() 方法 查询条件为顾客中年龄大于25且 order_visible为true(即顾客的年龄为奇数)