hibernate5--to 1 (n:1)-fetch= "select"-lazy= "false"

1. Create project, project name hibernatedemo27, directory structure

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2. Create a Lib directory storage jar file in the project, directory structure

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3. Create the Entity Class Forum, package name (Com.mycompany.demo.bean) in the SRC directory,

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4. The content of the entity forum is as follows

Package Com.mycompany.demo.bean;import Java.util.set;public class Forum {private int fid;private String name;private Set <ForumPost> forumposts;public int Getfid () {return FID;} public void Setfid (int fid) {this.fid = FID;} Public String GetName () {return name;} public void SetName (String name) {this.name = name;} Public set<forumpost> getforumposts () {return forumposts;} public void Setforumposts (set<forumpost> forumposts) {this.forumposts = forumposts;}}

5. Create the Entity Class Forum mapping file in the SRC directory Forum.hbm.xml, package name (Com.mycompany.demo.bean),

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6. The contents of the mapping file Forum.hbm.xml are as follows

<?xml version= "1.0"  encoding= "Utf-8"? ><! doctype hibernate-mapping public   "-//hibernate/hibernate mapping dtd//en"   "HTTP://WWW.HIBERNATE.ORG/DTD/HIBERNATE-MAPPING-3.0.DTD" > <!--Package: Specify <class/> packages to be located    -->

7. Create the entity class Forumpost, package name (Com.mycompany.demo.bean) in the SRC directory,
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8. The contents of the entity class Forumpost are as follows
Package Com.mycompany.demo.bean;public class Forumpost {private int pid;private String subject;private Forum Forum; public int getpid () {return PID;} public void setpid (int pid) {this.pid = pid;} Public String Getsubject () {return subject;} public void Setsubject (String subject) {this.subject = subject;} Public forum Getforum () {return forum;} public void Setforum (Forum forum) {this.forum = Forum;}}

9. Create the Entity Class Forumpost mapping file ForumPost.hbm.xml, package name (Com.mycompany.demo.bean) in the SRC directory,
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10. The contents of the mapping file ForumPost.hbm.xml are as follows
<?xml version= "1.0"  encoding= "Utf-8"? ><! doctype hibernate-mapping public   "-//hibernate/hibernate mapping dtd//en"   "HTTP://WWW.HIBERNATE.ORG/DTD/HIBERNATE-MAPPING-3.0.DTD" > <!--Package: Specify <class/> packages to be located    -->

11. Create the tool class Hbnutil, package name (com.mycompany.demo.util) in the SRC directory,
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12. The contents of the tool class Hbnutil are as follows
Package Com.mycompany.demo.util;import Org.hibernate.session;import Org.hibernate.sessionfactory;import Org.hibernate.cfg.configuration;public class Hbnutil {private static sessionfactory sessionfactory;public static Session getsession () {if (sessionfactory = = NULL | | sessionfactory.isclosed ()) {sessionfactory = new Configuration (). Configure (). Buildsessionfactory ();} return sessionfactory.getcurrentsession ();}}

13. Create the Hibernate profile Hibernate.cfg.xml in the SRC directory,
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The contents of the 14.Hibernate configuration file Hibernate.cfg.xml are as follows
<?xml version= "1.0"  encoding= "Utf-8"? ><! doctype hibernate-configuration system  "http://www.hibernate.org/dtd/ Hibernate-configuration-3.0.dtd ">

15. Create the test directory in the project to store testing files, file name TestApp, package name (Com.mycompany.demo.bean), directory structure
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The contents of the 16.TESTAPP test class are as follows
package com.mycompany.demo.bean;import java.util.hashset;import java.util.list;import  java.util.set;import org.hibernate.criteria;import org.hibernate.session;import  org.hibernate.sql.jointype;import org.junit.before;import org.junit.test;import  com.mycompany.demo.util.hbnutil;public class testapp {private session session;@ Beforepublic void init () {session = hbnutil.getsession ();} /* *  one-to-many bidirectional association-add  *  need to set the Set property in Forum.hbm.xml to Cascade= "All"  */@Testpublic  void  testonetomanyadd () {try {session.begintransaction (); Forumpost forumpost1 = new forumpost (); Forumpost1.setsubject ("A"); Forumpost forumpost2 = new forumpost (); Forumpost2.setsubject ("B"); Set<forumpost> forumposts = new hashset<forumpost> (); ForumPosts.add (ForumPost1 ); Forumposts.add (FORUMPOST2); Forum forum = new forum (); Forum.setname ("Foruma"); forum.setforumposts (forumposts); Session.save (forum); Session.gettransaction (). Commit () ;}  catch  (exception e)  {session.gettransaction (). rollback (); E.printstacktrace ();}} /* *  Many-to-one bidirectional association-fetch= "select", lazy= "false"  */@Testpublic  void testfetchforselect () {try  {session.begintransaction (); Forumpost forumpost = session.get (FORUMPOST.CLASS,&NBSP;10); Forum forum = forumpost.getforum (); System.out.println (Forum.getfid ()); System.out.println (Forum.getname ()); Session.gettransaction (). commit ();}  catch  (exception e)  {session.gettransaction (). rollback (); E.printstacktrace ();}}
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This article from the "Vegetarian Yan" blog, declined to reprint!
hibernate5--to 1 (n:1)-fetch= "select"-lazy= "false"