Hibernate+Spring实现多对一关联

最新推荐文章于 2024-10-12 07:46:51 发布

原创最新推荐文章于 2024-10-12 07:46:51 发布 · 955 阅读

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CC 4.0 BY-SA版权

文章标签：

#spring #hibernate #generator #class #table #encoding

本文介绍使用Oracle创建用户及博客表，并通过Hibernate进行多表查询。针对查询中出现的Session关闭异常，提供了配置OpenSessionInViewFilter解决方案。

我用的是Oracle：两个表

-- 创建用户表
CREATE TABLE SCOTT.bloguser
(
    id    NUMBER NOT NULL,
    username    VARCHAR2(50) UNIQUE NOT NULL,
    password    VARCHAR2(50) NOT NULL,
    CONSTRAINT PK_bloguser PRIMARY KEY (id )
);
-- 创建用户表主键序列
CREATE SEQUENCE SEQ_BLOGUSERID START WITH 1 INCREMENT BY 1 MINVALUE 1 NOCACHE  NOCYCLE  NOORDER ;

-- 创建bolg表
CREATE TABLE SCOTT.bolginfo
(
    id    NUMBER,
    userId    NUMBER NOT NULL,
    content    VARCHAR2(1000),
    CONSTRAINT PK_bolginfo PRIMARY KEY (id )
);
-- 创建bolg表主键序列
CREATE SEQUENCE SEQ_BLOGID START WITH 1 INCREMENT BY 1 MINVALUE 1 NOCACHE  NOCYCLE  NOORDER ;

--添加外键约束
ALTER TABLE SCOTT.bolginfo
    ADD CONSTRAINT FK_userId_blogId FOREIGN KEY (userId) REFERENCES SCOTT.bloguser(id);

Bloguser.java

package com.jam.hibeinate.po;

import java.util.Set;

/**
* Bloguser entity.
*
* @author Jam Chan
*/
public class Bloguser implements java.io.Serializable {

    private Long id;
    private String username;
    private String password;
    private Set bolginfos = new HashSet(0);
}

Bolginfo.java

package com.jam.hibeinate.po;

/**
* Bolginfo entity.
*
* @author Jam Chan
*/
public class Bolginfo implements java.io.Serializable {

    private Long id;
    private Bloguser bloguser;
    private String content;

}

Bloguser.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.jam.hibeinate.po.Bloguser" table="BLOGUSER" schema="SCOTT">
        <id name="id" type="java.lang.Long">
            <column name="ID" precision="22" scale="0" />
            <generator class="sequence">
                <param name="sequence">
                    SEQ_BLOGUSERID
                </param>
            </generator>
        </id>
        <property name="username" type="java.lang.String">
            <column name="USERNAME" length="50" not-null="true" unique="true" />
        </property>
        <property name="password" type="java.lang.String">
            <column name="PASSWORD" length="50" not-null="true" />
        </property>
        <set name="bolginfos" inverse="true" cascade="all" lazy="false" outer-join="auto">
            <key>
                <column name="USERID" precision="22" scale="0" not-null="true" />
            </key>
            <one-to-many class="com.jam.hibeinate.po.Bolginfo" />
        </set>
    </class>
</hibernate-mapping>

Bolginfo.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.jam.hibeinate.po.Bolginfo" table="BOLGINFO" schema="SCOTT">
        <id name="id" type="java.lang.Long">
            <column name="ID" precision="22" scale="0" />
            <generator class="sequence">
                <param name="sequence">SEQ_BLOGID</param>
            </generator>
        </id>
        <many-to-one name="bloguser" class="com.jam.hibeinate.po.Bloguser" fetch="select" insert="true" update="true" outer-join="true">
            <column name="USERID" precision="22" scale="0" not-null="true" />
        </many-to-one>
        <property name="content" type="java.lang.String">
            <column name="CONTENT" length="1000" />
        </property>
    </class>
</hibernate-mapping>

注：Spring的applicationContext.xml事务代理管理的配置省略……

之前我实现多表查询的时候抛出

could not initialize proxy - the owning Session was closed
org.hibernate.LazyInitializationException: could not initialize proxy - the owning Session was closed
……………………

的异常，如果想使Session is opened需要在web.xml添加如下配置：

<filter>
        <filter-name>openSessionInViewFilter</filter-name>
        <filter-class>
            org.springframework.orm.hibernate3.support.OpenSessionInViewFilter
        </filter-class>
    </filter>
    
    <filter-mapping>
        <filter-name>openSessionInViewFilter</filter-name>
        <url-pattern>*.faces</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>openSessionInViewFilter</filter-name>
        <url-pattern>*.do</url-pattern>
    </filter-mapping>
    <filter-mapping>
        <filter-name>openSessionInViewFilter</filter-name>
        <url-pattern>*.jsp</url-pattern>
    </filter-mapping>

之后就OK啦~！！哈哈