Migration from J2EE to. net
By Vivek Devarajan.
Hi all, here are some quick tips to get you started, in case you need to migrate a J2EE based application to A. Net Based application.
We approach the migration tier wise. Firstly, a technology mapping between both the platforms :--
| Service or feature | . Net | J2EE |
| Gui | Winforms | Swing & AWT |
| Web GUI | ASP. NET | JSP |
| Web Scripting | ISAPI, httphandler, httpmodule | Servlet, filter |
| Server side business logic component | Serviced component (COM +) | EJB session beans |
| Server Side data component | Serviced component (COM +) with DB Logic | Ejb bmp entity beans |
| Server Side data component | Object Spaces | Ejb cmp Entity beans |
| Naming | ADSI | JNDI |
| Remote Invocation | . Net remoting | RMI or RMI-IIOP |
| Data Access | Ado. net | JDBC |
| Messaging | MSMQ | JMS |
| Transactions | COM + or MTS | JTA |
Highlights of the migration strategy
I. Presentation tier migration
JSP scriptlet :--
<! -- Scriptlet --> <% for (INT I = 0; I <3; I ++) {out. println (I + "<br>") ;}%>
ASP. NET scriptlet :--
<! -- Scriptlet --> <% for (INT I = 0; I <3; I ++) {response. Write (I + "<br>") ;}%>
JSP expression :--
<% = New java. Math. bigdecimal (10.1). Negate () %>
ASP. NET expression :--
<% = System. Decimal. Negate (new system. Decimal (10.1) %>
JSP Declaration :--
<%! Public String Foo () {return "foo" ;}%>
ASP. NET Declaration :--
<SCRIPT runat = "server" Language = "C #"> Public Virtual string Foo () {return "foo" ;}</SCRIPT> | JSP | ASP. NET |
| Application | Application |
| Session | Session |
| Request | Request |
| Response | Response |
| Out | Response. Write |
Creating a cookie and setting its expiry time.
Code in J2EE :--
<% Cookie usercookie = new cookie ("user", "uid123"); usercookie. setmaxage (60*60*24*365); // 1 year response. addcookie (usercookie); %> Code in. Net :--
<% System. web. httpcookie usercookie = new system. web. httpcookie ("user", "uid123"); system. datetime = system. datetime. now; system. timespan = new system. timespan (0, 0, 60*60*24*365); // 1 year cookie. expires = datetime. add (timespan); response. cookies. add (usercookie); %>
Java code :--
Public class bean1 {private string text = "hello"; Public bean1 () {} Public String gettext () {return this. text;} Public String settext (string text) {This. TEXT = text ;}}
C # code :--
Using system; public class bean1 {private string text = "hello"; Public bean1 () {}public string text {get {return text ;}set {text = value ;}}}
Servlet sample code :--
Import javax. servlet. *; import javax. servlet. HTTP. *; import Java. io. *; public class simpleservlet extends httpservlet {public void doget (httpservletrequest request, httpservletresponse response) throws servletexception, Java. io. ioexception {response. setcontenttype ("text/html"); printwriter out = response. getwriter (); out. println ("<HTML> <body>"); out. println ("simple servlet body"); out. println ("</body> ASP. NET code-behind sample :--
Using system; using system. web; using system. web. ui; public class simpleservlet: system. web. UI. page {private void page_load (Object sender, eventargs ARGs) {response. contenttype = "text/html"; response. write ("<HTML> <body>"); response. write ("simple servlet body"); response. write ("</body>
| JSP | ASP. NET |
| Tag handler class JSP tag library Descriptor JSP tag library Directive |
ASP. NET web user controls ASP. NET web custom control |
JSP tag lib sample code :--
<!? JSP --> <!? The source file is specified in the TLD --> <% @ taglib uri = "taglib. TLD" prefix = "tags" %> <tags: Sample/>
ASP. NET tag lib sample code :--
<!? ASP. net --> <% @ register tagprefix = "tags" tagname = "sample" src = "exampletag. ascx "%> <tags: Sample id =" mysample "runat =" server "/>
Applet code :--
Package helloworldpackage; public class helloworld extends applet {public void paint (Graphics g) {G. drawstring (getparameter ("parameter1"), 25, 25);} public void Init () {} public void start () {} public void stop (){}}
. Net winforms code :--
Namespace helloworldpackage {public class helloworld: system. windows. forms. usercontrol {string parameter1; bool isactive; Public helloworld () {Init ();} protected override void onpaint (painteventargs e) {e. graphics. drawstring (parameter1, Font, new solidbrush (forecolor), 25, 25);} public void Init () {This. gotfocus + = new eventhandler (this. helloworldcontrol1_start); this. lostfocus + = new eventhandler (this. helloworldcontrol1_stop );}}
Ii. Business tier migration
EJB code: -- (Session Bean)
Public class tellerbean implements sessionbean {public void ejbcreate () {} public void ejbremove () throws RemoteException {} public void ejbactivate () throws RemoteException {} public void ejbpassivate () throws RemoteException {} Public String getdata () {return "some data ";}}
. Net code: -- (serviced component corresponding to the Java session bean)
[Transaction (transactionoption. required)] public class tellerbean: system. enterpriseservices. servicedcomponent {Public Virtual string data {get {return "some data" ;}} public void create () {}protected override void activate () {} protected override void deactivate () {} protected void remove {deactivate (); dispose ();}}
EJB code: -- (Entity Bean)
Public class accountentity implements entitybean {private string accountid; private int balance; Public getaccountid (){?} Public getbalance (){?} Public setbalance (INT amount ){?} }
Public class accountprocess implements entitybean {public accountentity [] inquiry (){?}; Public void insert (accountentity account) {string strquery = "select * From tb_account ";? } Public void Update (accountentity account ){?} Public void Delete (string accountid ){?}}
. Net code: -- (serviced component corresponding to the Java entity bean)
[Transaction (transactionoption. Required)] public struct accountentity {private string accountid; private int balance; Public accountid {get {?} } Public balance {get {?} Set {?} }}
// Dsaccount. XSD public class dsaccount: system. Data. dataset {?} Public class accountprocess: system. enterpriseservices. servicedcomponent {public dsaccount inquiry (){? } Public void insert (accountentity account) {dbagent. executenonquery ("sp_getaccount", paramarray ,?; ? } Public void insert (string accountid, int balance ,?) {? } // Alternative}
Create prodecure sp_getaccount @ accountid char (8), @ balance int ,? As ..
Java code :--
<% Try {context CTX = new initialcontext (); Object ref = CTX. lookup ("tellerhome"); tellerhome = (tellerhome) portableremoteobject. narrow (ref, tellerhome. class); teller = tellerhome. create (); out. println (Teller. getdata ();} catch (exception ex) {out. println (ex. getmessage () ;}%>. Net code :--
<% Mypackage. tellerbean teller = new mypackage. tellerbean (); response. Write (Teller. data); %>
Iii. Data tier migration
Java: -- (JDBC)
Class. forname ("com. ms. JDBC. ODBC. jdbcodbcdriver "); dburl =" JDBC: ODBC: adotest "; Conn = drivermanager. getconnection (dburl, "sa ","");. Net (ADO. Net ):--
Dburl = "provider = sqloledb; Data Source = dbserver; initial catalog = Master;"; using (oledbconnection conn = new oledbconnection (dburl) {Conn. open ();...}Java: -- (JDBC)
Statement S = conn. createstatement (); createtablebooks = "select count (au_lname) as nrows from authors"; resultset rs = s.exe cutequery (createtablebooks );
. Net (ADO. Net)
String explain text = "select count (au_lname) as nrows from authors"; using (oledbcommand cmd = new oledbcommand (gradient text, Conn) {oledbdatareader rs = cmd. executereader ();...}
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