级联操作以及session延迟关闭

首页说级联操作的基本配置：
在实体中定义操作关联的对象
实体：

package com.tosit.ligc.entity;

import java.util.Date;
import java.util.Set;

public class Part {
	private Integer part_id;
	private Integer par_Part_id;
	private String part_name;
	private String part_content;
	private Date part_time;
	private String part_img;
	private Set<Part> part;
	private Set<Img> img;
	
	public Set<Part> getPart() {
		return part;
	}
	public void setPart(Set<Part> part) {
		this.part = part;
	}
	private Set<News> newsset;

	public Set<Img> getImg() {
		return img;
	}
	public void setImg(Set<Img> img) {
		this.img = img;
	}
	public Set<News> getNewsset() {
		return newsset;
	}
	public void setNewsset(Set<News> newsset) {
		this.newsset = newsset;
	}
	public Integer getPart_id() {
		return part_id;
	}
	public Part() {
		super();
	}
	public void setPart_id(Integer part_id) {
		this.part_id = part_id;
	}
	
	public String getPart_name() {
		return part_name;
	}
	public void setPart_name(String part_name) {
		this.part_name = part_name;
	}
	public String getPart_content() {
		return part_content;
	}
	public void setPart_content(String part_content) {
		this.part_content = part_content;
	}
	public Date getPart_time() {
		return part_time;
	}
	public void setPart_time(Date part_time) {
		this.part_time = part_time;
	}
	
	public Integer getPar_Part_id() {
		return par_Part_id;
	}
	public void setPar_Part_id(Integer par_Part_id) {
		this.par_Part_id = par_Part_id;
	}
	public String getPart_img() {
		return part_img;
	}
	public void setPart_img(String part_img) {
		this.part_img = part_img;
	}	
}

package com.tosit.ligc.entity;

public class Img {

	private Integer img_id;
	private String img_url;
	private String img_title;
	private Integer news_id;
	private Integer foods_id;
	private Integer stay_id;
	private Part part;
	
	public Part getPart() {
		return part;
	}
	public void setPart(Part part) {
		this.part = part;
	}
	public Integer getImg_id() {
		return img_id;
	}
	public void setImg_id(Integer img_id) {
		this.img_id = img_id;
	}
	public String getImg_url() {
		return img_url;
	}
	public void setImg_url(String img_url) {
		this.img_url = img_url;
	}
	public String getImg_title() {
		return img_title;
	}
	public void setImg_title(String img_title) {
		this.img_title = img_title;
	}
	public Integer getNews_id() {
		return news_id;
	}
	public void setNews_id(Integer news_id) {
		this.news_id = news_id;
	}
	public Integer getFoods_id() {
		return foods_id;
	}
	public void setFoods_id(Integer foods_id) {
		this.foods_id = foods_id;
	}
	public Integer getStay_id() {
		return stay_id;
	}
	public void setStay_id(Integer stay_id) {
		this.stay_id = stay_id;
	}		
}

配置文件：
Part.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
        <!-- package 实体所在的包名 -->
      <hibernate-mapping package="com.tosit.ligc.entity">
      	<class name="Part" table="part">
      		<id name="part_id">
      			<generator class="increment"></generator>
      		</id>
      		<property name="part_name"></property>
      		<property name="part_content"></property>
      		<property name="part_time" ></property>
      		<!-- 级联操作 -->
      		<!-- 延迟加载 -->
      		<many-to-one name="par_Part_id" class="Part" column="par_Part_id" lazy="proxy" not-null="true" >
        	</many-to-one>
      		
      		<set name="part" table="part" cascade="all"  inverse="true">
<!--cascade: 它用于指定如何操纵与当前对象关联的其他对象 all表示所有，还有save-update persist,merge,delete等等 Inverse：负责控制关系，默认为false，也就是关系的两端都能控制，如果为ture表示把 关系交给对方控制，一般情况为true not-null表示保存时候不能为空 -->
      			<key column="par_Part_id" not-null="true"></key>
      			<one-to-many class="Part" />
      		
      		</set>
      		
      		<set name="img" table="img" cascade="all"  inverse="true">
      			<key column="part_id"></key>
      		<one-to-many class="Img"/>
      		</set>	
      	</class>	
      </hibernate-mapping> 

Img.hbm.xml:

<?xml version="1.0" encoding="UTF-8"?>
<!DOCTYPE hibernate-mapping PUBLIC
        "-//Hibernate/Hibernate Mapping DTD 3.0//EN"
        "http://www.hibernate.org/dtd/hibernate-mapping-3.0.dtd">
        <hibernate-mapping package="com.tosit.ligc.entity">
        	<class name="Img" table="img">
        	<id name="img_id">
        	<generator class="native"></generator>
        	</id>
        	<property name="img_url"></property>
        	<property name="img_title"></property>
        	<property name="news_id"></property>
        	<property name="foods_id"></property>
        	<property name="stay_id"></property>
        	<many-to-one name="part" class="Part" column="part_id" lazy="proxy" not-null="true"/>
        	</class>
      </hibernate-mapping>

写代码的时候，在Controller中使用关联表的数据是否报no session错误。百度一下是因为在applicationContext.xml 中用来延迟加载

default-lazy-init="true" default-autowire="byName">

<!-- 是否延迟加载。通过名字实现自动装配 -->
在控制器调用的时候就会报no session 错误。因为session 在hibernate执行之后会自动关闭。所以找不到

package com.tosit.ligc.web;

import java.util.HashSet;
import java.util.List;
import java.util.Set;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.jdbc.core.metadata.HanaCallMetaDataProvider;
import org.springframework.stereotype.Controller;
import org.springframework.ui.ModelMap;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestParam;

import com.tosit.ligc.entity.News;
import com.tosit.ligc.entity.Part;
import com.tosit.ligc.service.PartService;
@Controller
public class PartController {
	@Autowired
	@Qualifier("partService")
	private PartService partService;
	/**
	 获取一级栏目信息
	 */
	@RequestMapping("/index")
	public  String index(ModelMap map){
    List<Part>	partlist =	partService.getPartlist();
	map.put("partlist", partlist);
	return "index";
	}
	/**
	 * 获取二级栏目信息
	 * 
	 */
	@RequestMapping("/onePart")
	public String onePart(ModelMap map,@RequestParam(value="id")Integer id){
		String result = "index";
		List<Part> onelist = partService.getPartlist(id);
		map.put("onelist", onelist);
		if(id==1){
			result="index";
		}else{
			result ="Second/Lj-NewList";
		}
		return result;
		
	}
	/**
	 * 获取动态信息
	 * 
	 */
	
	@RequestMapping("/newslist")
	public String newslist(ModelMap map,@RequestParam(value="id")Integer id){
		this.index(map);
		List<News> list = partService.getnewlist(id);
		map.put("list", list);
		return "Second/Lj-NewList";
	}
	
}

解决方案：在web.xml 配置一个过滤器。是hibernate自带的一个session延迟关闭过滤。注意的是在hibernate3和hibernate4配置的不一样。当然还有一种就是把延迟加载关闭，但是这样数据大了之后，造成服务器运行效率级低。

<!-- 可以使spring自动事务延迟到视图解析后（用完数据后）才关闭 ，解决hibernate的延迟加载问题-->
	<filter>
		<filter-name>osivFilter</filter-name>
		<filter-class>org.springframework.orm.hibernate4.support.OpenSessionInViewFilter</filter-class>
		<init-param>
			<!-- 指定过滤器使用的sessionFactory bean id，默认就是sessionFactory -->
			<param-name>sessionFactoryBeanName</param-name>
			<param-value>sessionFactory</param-value>
		</init-param>
	</filter>
	<filter-mapping>
		<filter-name>osivFilter</filter-name>
		<url-pattern>/*</url-pattern>
	</filter-mapping>