fetch 属性和 property-ref属性

java pojo类和hibernate映射文件分别为：

 

/**
 * SysRepeaterMng entity.
 * 
 * @author MyEclipse Persistence Tools
 */
public class SysRepeaterMng implements java.io.Serializable {
 // Fields
 /**
  * 
  */
 private static final long serialVersionUID = -7028035445611074921L;
 private Long id;
 private String reptSid;
 private String reptNam;
 private String reptIp;
 private Date joinTime;
 private String memo;
 private Long state;
 private String password;
 private Long isserver;
 private Long publishmode;
 //private String stateCN;//服务器状态 中文名称
 //private String isserverCN;//服务器类型 中文名称
 //private String publishmodeCN;//服务器发布方式 中文名称
 private Set itemPublishFails;
 // Constructors
 /**
  * @return the itemPublishFails
  */
 public Set getItemPublishFails() {
  return itemPublishFails;
 }
 /**
  * @param itemPublishFails the itemPublishFails to set
  */
 public void setItemPublishFails(Set itemPublishFails) {
  this.itemPublishFails = itemPublishFails;
 }
 /** default constructor */
 public SysRepeaterMng() {
 }
 /** minimal constructor */
 public SysRepeaterMng(Long id, String reptSid, String reptNam,
   String reptIp, Date joinTime, Long state,Set itemPublishFails) {
  this.id = id;
  this.reptSid = reptSid;
  this.reptNam = reptNam;
  this.reptIp = reptIp;
  this.joinTime = joinTime;
  this.state = state;
  this.itemPublishFails = itemPublishFails;
 }
 /** full constructor */
 public SysRepeaterMng(Long id, String reptSid, String reptNam,
   String reptIp, Date joinTime, String memo, Long state,
   String password,Set itemPublishFails) {
  this.id = id;
  this.reptSid = reptSid;
  this.reptNam = reptNam;
  this.reptIp = reptIp;
  this.joinTime = joinTime;
  this.memo = memo;
  this.state = state;
  this.password = password;
  this.itemPublishFails = itemPublishFails;
  
 }
 // Property accessors
 public Long getId() {
  return this.id;
 }
 public void setId(Long id) {
  this.id = id;
 }
 public String getReptSid() {
  return this.reptSid;
 }
 public void setReptSid(String reptSid) {
  this.reptSid = reptSid;
 }
 public String getReptNam() {
  return this.reptNam;
 }
 public void setReptNam(String reptNam) {
  this.reptNam = reptNam;
 }
 public String getReptIp() {
  return this.reptIp;
 }
 public void setReptIp(String reptIp) {
  this.reptIp = reptIp;
 }
 public Date getJoinTime() {
  return this.joinTime;
 }
 public void setJoinTime(Date joinTime) {
  this.joinTime = joinTime;
 }
 public String getMemo() {
  return this.memo;
 }
 public void setMemo(String memo) {
  this.memo = memo;
 }
 public Long getState() {
  return this.state;
 }
 public void setState(Long state) {
  this.state = state;
 }
 public String getPassword() {
  return this.password;
 }
 public void setPassword(String password) {
  this.password = password;
 }
 /**
  * @return the isserver
  */
 public Long getIsserver() {
  return isserver;
 }
 /**
  * @param isserver
  *            the isserver to set
  */
 public void setIsserver(Long isserver) {
  this.isserver = isserver;
 }
 /**
  * @return the publishmode
  */
 public Long getPublishmode() {
  return publishmode;
 }
 /**
  * @param publishmode
  *            the publishmode to set
  */
 public void setPublishmode(Long publishmode) {
  this.publishmode = publishmode;
 }
}

 

 

 

<?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">
<!-- 
 Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
 <class name="com.SysRepeaterMng"
  table="SYS_REPEATER_MNG" schema="ZHENGJIANG">
  <id name="id" type="java.lang.Long">
   <column name="ID" precision="10" scale="0" />
   <generator class="sequence">
    <param name="sequence">SYSREPEATERMNG_sequence</param>
   </generator>
  </id>
  <property name="reptSid" type="java.lang.String">
   <column name="REPT_SID" length="10" not-null="true"
    unique="true" />
  </property>
  <property name="reptNam" type="java.lang.String">
   <column name="REPT_NAM" length="50" not-null="true" />
  </property>
  <property name="reptIp" type="java.lang.String">
   <column name="REPT_IP" length="50" not-null="true" />
  </property>
  <property name="joinTime" type="java.util.Date">
   <column name="JOIN_TIME" length="7" not-null="true" />
  </property>
  <property name="memo" type="java.lang.String">
   <column name="MEMO" length="256" />
  </property>
  <property name="state" type="java.lang.Long">
   <column name="STATE" precision="1" scale="0"
    not-null="true" />
  </property>
  <property name="password" type="java.lang.String">
   <column name="PASSWORD" length="20" />
  </property>
  <property name="isserver" type="java.lang.Long">
   <column name="IS_SERVER" precision="1" scale="0"
    not-null="true" />
  </property>
  <property name="publishmode" type="java.lang.Long">
   <column name="PUBLISH_MODE" precision="1" scale="0"
    not-null="true" />
  </property>
  <set name="itemPublishFails" 
    table="ITEM_PUBLISH_FAIL"
    inverse="true"
    lazy="false"
    cascade="all">
   <key column="REPT_SID"></key>
   <one-to-many class="com.ItemPublishFail"/>
  </set>
 </class>
</hibernate-mapping>

 

 

/**
 * ItemPublishFail entity.
 * 
 * @author MyEclipse Persistence Tools
 */
public class ItemPublishFail implements java.io.Serializable {
 // Fields
 /**
  * 
  */
 private static final long serialVersionUID = -3002520851890289401L;
 private Long itemId;
 private String channelNam;
 private Integer channelTpid;
 private String mediaType;
 private Integer codeRate;
 private Integer publishMode;
 private Integer pubPrv;
 private Date failTime;
 private String channelUrl;
 private String channelPic;
 private String channelDesc;
 private String keyWord;
 private SysRepeaterMng sysRepeaterMng;
 // Constructors
 /** default constructor */
 public ItemPublishFail() {
 }
 /** full constructor */
 public ItemPublishFail(String channelNam, Integer channelTpid,
   String mediaType, Integer codeRate, Integer publishMode, Integer pubPrv,
   Date failTime, String channelUrl, String channelPic,
   String channelDesc, String keyWord, SysRepeaterMng sysRepeaterMng) {
  this.channelNam = channelNam;
  this.channelTpid = channelTpid;
  this.mediaType = mediaType;
  this.codeRate = codeRate;
  this.publishMode = publishMode;
  this.pubPrv = pubPrv;
  this.failTime = failTime;
  this.channelUrl = channelUrl;
  this.channelPic = channelPic;
  this.channelDesc = channelDesc;
  this.keyWord = keyWord;
  this.sysRepeaterMng = sysRepeaterMng;
 }
 // Property accessors
 public Long getItemId() {
  return this.itemId;
 }
 public void setItemId(Long itemId) {
  this.itemId = itemId;
 }
 public String getChannelNam() {
  return this.channelNam;
 }
 public void setChannelNam(String channelNam) {
  this.channelNam = channelNam;
 }
 public Integer getChannelTpid() {
  return this.channelTpid;
 }
 public void setChannelTpid(Integer channelTpid) {
  this.channelTpid = channelTpid;
 }
 public String getMediaType() {
  return this.mediaType;
 }
 public void setMediaType(String mediaType) {
  this.mediaType = mediaType;
 }
 public Integer getCodeRate() {
  return this.codeRate;
 }
 public void setCodeRate(Integer codeRate) {
  this.codeRate = codeRate;
 }
 public Integer getPublishMode() {
  return this.publishMode;
 }
 public void setPublishMode(Integer publishMode) {
  this.publishMode = publishMode;
 }
 public Integer getPubPrv() {
  return this.pubPrv;
 }
 public void setPubPrv(Integer pubPrv) {
  this.pubPrv = pubPrv;
 }
 public Date getFailTime() {
  return this.failTime;
 }
 public void setFailTime(Date failTime) {
  this.failTime = failTime;
 }
 public String getChannelUrl() {
  return this.channelUrl;
 }
 public void setChannelUrl(String channelUrl) {
  this.channelUrl = channelUrl;
 }
 public String getChannelPic() {
  return this.channelPic;
 }
 public void setChannelPic(String channelPic) {
  this.channelPic = channelPic;
 }
 public String getChannelDesc() {
  return this.channelDesc;
 }
 public void setChannelDesc(String channelDesc) {
  this.channelDesc = channelDesc;
 }
 public String getKeyWord() {
  return this.keyWord;
 }
 public void setKeyWord(String keyWord) {
  this.keyWord = keyWord;
 }
 /**
  * @return the sysRepeaterMng
  */
 public SysRepeaterMng getSysRepeaterMng() {
  return sysRepeaterMng;
 }
 /**
  * @param sysRepeaterMng the sysRepeaterMng to set
  */
 public void setSysRepeaterMng(SysRepeaterMng sysRepeaterMng) {
  this.sysRepeaterMng = sysRepeaterMng;
 }
}

 

 

<?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">
<!-- 
 Mapping file autogenerated by MyEclipse Persistence Tools
-->
<hibernate-mapping>
 <class name="com.ItemPublishFail"
  table="ITEM_PUBLISH_FAIL" schema="ZHENGJIANG" >
  <id name="itemId" type="java.lang.Long">
   <column name="ITEM_ID" precision="6" scale="0" />
   <generator class="sequence">
    <param name="sequence">ITEMPUBLISHFAIL_SEQUENCE</param>
   </generator>
  </id>
  <property name="channelNam" type="java.lang.String">
   <column name="CHANNEL_NAM" length="100" not-null="true" />
  </property>
  <property name="channelTpid" type="java.lang.Integer">
   <column name="CHANNEL_TPID" precision="3" scale="0"
    not-null="true" />
  </property>
  <property name="mediaType" type="java.lang.String">
   <column name="MEDIA_TYPE" length="10" not-null="true" />
  </property>
  <property name="codeRate" type="java.lang.Integer">
   <column name="CODE_RATE" precision="10" scale="0"
    not-null="true" />
  </property>
  <property name="publishMode" type="java.lang.Integer">
   <column name="PUBLISH_MODE" precision="1" scale="0"
    not-null="true" />
  </property>
  <property name="pubPrv" type="java.lang.Integer">
   <column name="PUB_PRV" precision="1" scale="0"
    not-null="true" />
  </property>
  <property name="failTime" type="java.util.Date">
   <column name="FAIL_TIME" length="7" not-null="true" />
  </property>
  <property name="channelUrl" type="java.lang.String">
   <column name="CHANNEL_URL" not-null="true" />
  </property>
  <property name="channelPic" type="java.lang.String">
   <column name="CHANNEL_PIC" not-null="true" />
  </property>
  <property name="channelDesc" type="java.lang.String">
   <column name="CHANNEL_DESC" length="256" />
  </property>
  <property name="keyWord" type="java.lang.String">
   <column name="KEY_WORD" length="30" />
  </property>
  <many-to-one 
   name="sysRepeaterMng"
   class="com.SysRepeaterMng"
   property-ref="reptSid"
   column="REPT_SID"
   cascade="none"
   outer-join="auto"
   
   access="property"
   not-null="true"
   lazy="false"
   >
  </many-to-one>
 </class>
</hibernate-mapping>

问题一：属性fetch="join|select" 配置
 hibernate 官方网站对 many-to-one 属性 fetch="join|select" 的解释：
 fetch (optional - defaults to select): Chooses between outer-join fetching or sequential select fetching.
 
 如果该属性设置成join 时，hibernate会使用 sql 中的 outer-join 来关联两张表取数据，如果设置成select时，则
 hibernate会分别用两条select语句来取数据。

 当使用Criteria 的 criteria.list();来取数据时，如果设置成select时，则hibernate会先将SysRepeaterMng 填充进
 ItemPublishFail 中 再把数据填充到list 中，正确显示。
 如果设置成join时则hibernate会分别将SysRepeaterMng 和 ItemPublishFail 对象都放入list中，造成错误，具体原因还不清楚。

问题二：属性property-ref配置（该属性适用于遗留的数据库，既与一方关联的不是主键，而是唯一键）
       hibernate 数据库多对一关联时，如果一的那一方关联的字段不是表的主键，而是唯一键的话。则需要加另外的属性property-ref配置。
       查看hibernate官方文档：
       http://www.hibernate.org/hib_docs/v3/reference/en-US/html/mapping.html#mapping-declaration-manytoone
       many-to-one 属性
       property-ref: (optional) The name of a property of the associated class that is joined to
       this foreign key. If not specified, the primary key of the associated class is used.
       如果没有设置该属性，则hibernate会默认使用一方的主键，所以需要将该属性设置成一方的唯一键，这样hibernate在生成sql语句的时候才会正确使用唯一键来关联而不是使用主键关联。