Three-tier architecture for Java software Design

Interface:

 Package DAO;  Public Interface Dao {    String getData ();}

 Package Biz; Import DAO. Dao;  Public Interface Biz {    void  setdao (dao dao);    String dealData ();}

 Package view; Import Biz. Biz;  Public Interface View {    void  setbiz (Biz biz);     void showData ();}

Implementation class:

 PackageDAO;ImportJava.io.BufferedReader;Importjava.io.FileNotFoundException;ImportJava.io.FileReader;Importjava.io.IOException; Public classFiledaoimplImplementsDao {@Override Publicstring GetData () {String Data=NULL; BufferedReader BR=NULL; Try{br=NewBufferedReader (NewFileReader ("Test.txt")); Data=Br.readline (); }  Catch(IOException e) {//TODO auto-generated Catch blockE.printstacktrace (); }finally {            if(br!=NULL) {                Try{br.close (); } Catch(IOException e) {//TODO auto-generated Catch blockE.printstacktrace (); }            }        }        returndata; }}

 PackageBiz;ImportDAO. Dao; Public classUppercasebizimplImplementsBiz {PrivateDAO DAO; @Override Public voidsetdao (dao dao) { This. dao=DAO; } @Override Publicstring DealData () {String Data=Dao.getdata (); if(Data! =NULL) {data.touppercase (); }        returndata; }}

 package   view;  import   biz. Biz;  public  class  Textviewimpl implements   View { private   Biz Biz; @Override  public  void   Setbiz (Biz biz) { this . Biz= Biz; } @Override  public  void   ShowData () {String data  = Biz.dealdata ();    SYSTEM.OUT.PRINTLN (data); }}

Object Factory:

 PackageFactory;ImportJava.io.FileInputStream;Importjava.io.FileNotFoundException;Importjava.io.IOException;ImportJava.io.InputStream;Importjava.util.Properties;ImportBiz. Biz;Importview. View;ImportDAO. Dao; Public classSimplefactory {PrivateProperties Properties;  Publicsimplefactory () {Properties=NewProperties (); InputStream is=NULL; Try{ is=NewFileInputStream ("Conf.properties");        Properties.load (IS); }  Catch(IOException e) {//TODO auto-generated Catch blockE.printstacktrace (); }finally {            if(is!=NULL) {                Try{is.close (); } Catch(IOException e) {//TODO auto-generated Catch blockE.printstacktrace (); }            }        }    }         PublicDao Createdao () {String className= Properties.getproperty ("DAO"); return(Dao) CreateObject (ClassName); }     PublicBiz createbiz () {String className= Properties.getproperty ("Biz"); return(Biz) CreateObject (ClassName); }     PublicView CreateView () {String className= Properties.getproperty ("View"); return(View) CreateObject (ClassName); }    PrivateObject CreateObject (String name) {Object result=NULL; Try{Class Clazz=class.forname (name); Result=clazz.newinstance (); } Catch(ClassNotFoundException e) {//TODO auto-generated Catch blockE.printstacktrace (); } Catch(instantiationexception e) {//TODO auto-generated Catch blockE.printstacktrace (); } Catch(illegalaccessexception e) {//TODO auto-generated Catch blockE.printstacktrace (); }        returnresult; }}

Configuration file: Conf.properties

View=view. Textviewimpl
Biz=biz.uppercasebizimpl
Dao=dao.filedaoimpl

Text file: Test.txt

HELLO World

Test class:

 Packagetest;Importview. View;ImportBiz. Biz;ImportDAO. Dao;ImportFactory. Simplefactory; Public classTestmain {/**     * @paramargs*/     Public Static voidMain (string[] args) {simplefactory simplefactory=Newsimplefactory (); DAO DAO=Simplefactory.createdao (); Biz Biz=simplefactory.createbiz ();        Biz.setdao (DAO); View View=Simplefactory.createview ();        View.setbiz (Biz);    View.showdata (); }}

Output

HELLO World

Three-tier architecture for Java software Design