hibernate/SessionFactory">
8com.mysql.jdbc.Driver
9jdbc:
mysql:
//localhost/test
10username
11pwd
1210
13true
14org.hibernate.dialect.MySQLDialect
15update
16
--Mappingfiles-->
17
18
19
Tokeepthecodesimple,normallyIadddifferentconfigurationsfordifferentclassesinhibernate.
Whatistheneedofdialectinhibernate:
DatabasesimplementsubtledifferencesintheSQLtheyuse.ThingssuchasdatatypesforexamplevaryacrossdatabasesOrdatabasespecificfunctionality–selectingthetopnrowsisdifferentdependingonthedatabase.Thedialectabstractsthissoyoudon’thavetoworryaboutit.Inshortthedialectpropertyinternallycreatesthehighlyoptimizedqueryforunderlyingdatabase.
Herealso,asyoucansee,IhaveincludedfileChatMessage.hbm.xmlfile.
CodeofChatMessage.hbm.xml:
1
xmlversion="1.0"?
>
2
DOCTYPEhibernate-mappingPUBLIC
3"-//Hibernate/HibernateMappingDTD3.0//EN"
4"
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
UIPartoftheapplication:
FortheUI,Ihavewrittenlotsofcssclasses,thisisnotpossibletowritecompletecodehere.Pleasecheckthecodefromdownloadlinkprovidedatthebottomofthearticle.
UIofthechatwindowiscreatedtogivethefeeloftheGmailchatapplicationasshowninbelowimage:
Gmaillikechatwindowwithemoticons
Here,findthejavascriptcode,whichisresponsibletosendtheAJAXrequesttotheservlet,andgettingbacktheresponsecode:
1
2varuEnteredName=prompt（"PleaseEnterYourName"）;
3$（"#chat_Header"）.html（uEnteredName）;
4$（"#msg"）.focus（）;
5
6functionopenEmot（）
7{
8var$ele=$（"#emoticons"）;
9varvisibility=$ele.css（'display'）;
10
11if（visibility=='none'）
12{
13$ele.show（）;
14}
15else{
16$ele.hide（）;
17}
18}
19
20functionsmileyCode（iconCode）
21{
22var$msgEle=$（"#msg"）;
23$msgEle.val（$msgEle.val（）+iconCode）;
24var$ele=$（"#emoticons"）;
25$ele.hide（）;
26
27$msgEle.focus（）;
28}
29
30functionsaveChats（）{
31varuName=$（"#chat_Header"）.html（）;
32if（uName==''）{
33alert（'Pleaseenteryourname'）;
34returnfalse;
35}
36varmsg=$（"#msg"）.val（）;
37//varoldMsg=$（"#chat-area"）.html（）;
38varcolorCode=$（'input[name=nameColor]:
checked','#send-message-area'）
39.val（）;
40
41$.ajax（{
42type:
"POST",
43data:
"uName="+uName+"&msg="+msg+"&colorCode="
44+colorCode,
45url:
"Chatprocess.do",
46error:
function（xhr,ajaxOptions,thrownError）{
47alert（xhr.status）;
48alert（thrownError）;
49},
50success:
function（data）{
51$（"#chat-area"）.html（data）;
52$（"#ChatAtBigScreen"）.html（data）;
53document.getElementById（'chat-area'）.scrollTop=document.getElementById（'chat-area'）.scrollHeight;
54document.getElementById（'ChatAtBigScreen'）.scrollTop=document.getElementById（'ChatAtBigScreen'）.scrollHeight;
55}
56}）;
57returnfalse;
58}
59$（'#msg'）.keyup（function（e）{
60
61if（e.keyCode==13）{
62saveChats（）;
63$（"#msg"）.val（''）;
64}
65}）;
66
Utilityclass,responsibletosavethechatinthedatabaseusinghibernate:
1packagecom.G2.Model;
2
3importjava.util.ArrayList;
4importjava.util.Iterator;
5importjava.util.List;
6
7importorg.hibernate.Query;
8importorg.hibernate.Session;
9importorg.hibernate.SessionFactory;
10importorg.hibernate.Transaction;
11importorg.hibernate.cfg.Configuration;
12
13importcom.G2.pojo.ChatMessage;
14
15publicclassDBManager{
16//ReadHibernate.cfg.xml
17staticConfigurationcf=newConfiguration（）.configure（）;
18staticSessionFactoryfactory=cf.buildSessionFactory（）;
19
20publicstaticvoidsaveChat（ChatMessagechat）{
21
22Sessionsession=null;
23try{
24
25session=factory.openSession（）;
26Transactiontx=session.beginTransaction（）;
27
28session.save（chat）;
29mit（）;
30
31}catch（Exceptione）{
32e.printStackTrace（）;
33}finally{
34if（session!
=null）{
35//Ifacedproblemhere,ifbelowlineisnotwrittenthendataautomaticallygetsdeletedafterinsertion
36session.flush（）;
37session.close（）;
38}
39}
40}
41
42publicstaticListgetMessages（）{
43ListMessageList=newArrayList（）;
44Sessionsession=null;
45try{
46session=factory.openSession（）;
47StringSQL_QUERY="fromChatMessagec";
48Queryquery=session.createQuery（SQL_QUERY）;
49Iteratorit=query.iterate（）;
50while（it.hasNext（））{
51ChatMessagec=it.next（）;
52MessageList.add（c）;
53}
54
55}catch（Exceptione）{
56e.printStackTrace（）;
57}finally{
58session.flush（）;
59session.close（）;
60}
61
62returnMessageList;
63}
64}
Asshowninabovecode,toworkwithhibernate,ourapplicationwillneedtoreadtheconfigurationfileofhibernatebybelowlineofcode:
1staticConfigurationcf=newConfiguration（）.configure（）;
Now,wewillneedtocreatethesessionobjectfromtheSessionFactoryclass:
1staticSessionFactoryfactory=cf.buildSessionFactory（）;
2Sessionsession=factory.openSession（）;
Createtheobjectoftransaction:
1Transactiontx=session.beginTransaction（）;
Tosavetheobjectinthedatabaseusesave（）methodofthetransaction.
Togetthelistofchatmessagesfromthedatabase:
1StringSQL_QUERY="fromChatMessagec";
2Queryquery=session.createQuery（SQL_QUERY）;
3Iteratorit=query.iterate（）;
Hereobjectoforg.hibernate.Queryiscreatedandusingmethoditerate（）,itgivesalltherecordsfromthedatabaseasaobject.（ThatiswhatORM–ObjectRelationMapping）
ServletCode:
1packagecom.G2.servlets;
2
3importjava.io.IOException;
4importjava.io.PrintWriter;
5importjava.util.HashMap;
6importjava.util.List;
7
8importjavax.servlet.ServletException;
9importjavax.servlet.http.HttpServlet;
10importjavax.servlet.http.HttpServletRequest;
11importjavax.servlet.http.HttpServletResponse;
12
13importcom.G2.Model.DBManager;
14importcom.G2.pojo.ChatMessage;
15
16publicclassChatProcessextendsHttpServlet{
17
18@Override
19prot
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