Просмотр исходного текста страницы Java Tutorial/JSP/Class in JSP Page

==  Calling Superclass Constructors ==






   
  <!-- start source code -->
   
    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Calling Superclass Constructors</TITLE>
    </HEAD>
    <BODY>
        <H1>Calling Superclass Constructors</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class a
            {
                a() throws java.io.IOException 
                {
                    localOut.println("In a\"s constructor...<BR>");
                }
            }
            class b extends a
            {
                b() throws java.io.IOException 
                {
                    localOut.println("In b\"s constructor...<BR>");
                }
            }
        %>     
        <%
        localOut = out;     
        b obj = new b();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Creating a Java Interface ==






   
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    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Creating a Java Interface</TITLE>
    </HEAD>
    <BODY>
        <H1>Creating a Java Interface</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            interface Printem 
            {
                void printText() throws java.io.IOException;
            }
            class a implements Printem
            {
                public void printText() throws java.io.IOException
                {
                    localOut.println("Hello from JSP!");
                }
            }
        %>     
        <%
            localOut = out;     
            a printer = new a();
            printer.printText();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Overloading Methods ==






   
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    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Overloading Methods</TITLE>
    </HEAD>
    <BODY>
        <H1>Overloading Methods</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            void printText() throws java.io.IOException
            {
                localOut.println("Hello!<BR>");
            }
            void printText(String s) throws java.io.IOException
            {
                localOut.println(s + "<BR>");
            }
        %>     
        <%
        localOut = out;     
        printText();
        printText("Hello from JSP!");
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Overriding Methods in derived class ==






   
  <!-- start source code -->
   
    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Overriding Methods in derived class</TITLE>
    </HEAD>
    <BODY>
        <H1>Overriding Methods</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class BaseClass
            {
                public void print()  throws java.io.IOException 
                {
                    localOut.println("print in base...<BR>");
                }
            }
            class DerivedClass extends BaseClass
            {
                public void print()  throws java.io.IOException 
                {
                    localOut.println("print in Derived class...<BR>");
                }
            }
        %>     
        <%
            localOut = out;     
            out.println("Creating an animal object...<BR>");
            BaseClass a = new BaseClass();
            a.print();
            out.println();
            out.println("Creating a trout object...<BR>");
            DerivedClass t = new DerivedClass();
            t.print();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Runtime Polymorphism ==






   
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    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Runtime Polymorphism</TITLE>
    </HEAD>
    <BODY>
        <H1>Runtime Polymorphism</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from BaseClass...<BR>");
                }
            }
            class DerivedClass1 extends BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from DerivedClass1...<BR>");
                }
            }
            class DerivedClass2 extends BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from DerivedClass2...<BR>");
                }
            }
            class DerivedClass3 extends BaseClass
            {
                public void print() throws java.io.IOException 
                {
                    localOut.println("Hello from DerivedClass3...<BR>");
                }
            }
        %>     
        <%
            localOut = out;     
    
            BaseClass a1 = new BaseClass(); 
            DerivedClass1 b1 = new DerivedClass1(); 
            DerivedClass2 c1 = new DerivedClass2(); 
            DerivedClass3 d1 = new DerivedClass3(); 
            
            BaseClass baseClassVariable;
    
            baseClassVariable = a1;
            baseClassVariable.print();
    
            baseClassVariable = b1;
            baseClassVariable.print();
    
            baseClassVariable = c1;
            baseClassVariable.print();
    
            baseClassVariable = d1;
            baseClassVariable.print();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Using Abstract Classes ==






   
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    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Using Abstract Classes</TITLE>
    </HEAD>
    <BODY>
        <H1>Using Abstract Classes</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            abstract class a
            {
                abstract String getText() throws java.io.IOException;
                public void printem() throws java.io.IOException 
                {
                    localOut.println(getText());
                }
            }
            class b extends a
            {
                String getText() throws java.io.IOException 
                {
                    return "Hello from JSP!";
                }
            }
        %>     
        <%
            localOut = out;     
            b bObject = new b();
            bObject.printem();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Using Inheritance ==






   
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    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Using Inheritance</TITLE>
    </HEAD>
    <BODY>
        <H1>Using Inheritance</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class BaseClass
            {
                public void start()  throws java.io.IOException
                {
                    localOut.println("Starting...<BR>");
                }
            }
            class DerivedClass extends BaseClass
            {
                public void drive() throws java.io.IOException 
                {
                    localOut.println("Deriving...<BR>");
                }
            }
        %>     
        <%
            localOut = out;     
            out.println("Creating an DerivedClass...<BR>");
            DerivedClass a = new DerivedClass();
            a.start();
            a.drive();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Using Parameterized Constructors ==






   
  <!-- start source code -->
   
    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Using Parameterized Constructors</TITLE>
    </HEAD>
    <BODY>
        <H1>Using Parameterized Constructors</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class a
            {
                a() throws java.io.IOException 
                {
                    localOut.println("In a\"s constructor...<BR>");
                }
            }
            class b extends a  
            {
                b(String s) throws java.io.IOException 
                {
                    localOut.println("In b\"s String constructor...<BR>");
                    localOut.println(s);
                }
            }
        %>     
        <%
            localOut = out;     
            b obj = new b("Hello from JSP!<BR>");
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Using Restricted Access ==






   
  <!-- start source code -->
   
    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Using Restricted Access</TITLE>
    </HEAD>
    <BODY>
        <H1>Using Restricted Access</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class BaseClass
            {
                protected void start()  throws java.io.IOException
                {
                    localOut.println("Starting...<BR>");
                }
            }
            class DerivedClass extends BaseClass
            {
                public void drive() throws java.io.IOException 
                {
                    localOut.println("Driving...<BR>");
                }
            }
        %>     
        <%
            localOut = out;     
            out.println("Creating an DerivedClass...<BR>");
            DerivedClass a = new DerivedClass();
            a.start();
            a.drive();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Using Superclass Variables With Subclassed Objects ==






   
  <!-- start source code -->
   
    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Using Superclass Variables With Subclassed Objects</TITLE>
    </HEAD>
    <BODY>
        <H1>Using Superclass Variables With Subclassed Objects</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            class BaseClass
            {
                public void start() throws java.io.IOException 
                {
                    localOut.println("Starting...<BR>");
                }
            }
            class DerivedClass1 extends BaseClass
            {
                public void fly() throws java.io.IOException 
                {
                    localOut.println("Flying...<BR>");
                }
            }
            class DerivedClass2 extends DerivedClass1
            {
                public void fly() throws java.io.IOException 
                {
                    localOut.println("Flying...<BR>");
                }
            }
        %>     
        <%
            localOut = out;     
            out.println();
            out.println("Creating a DerivedClass2 object...<BR>");
            BaseClass p = new DerivedClass2();
            p.start();
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->
   




==  Working With Constructors and Inheritance ==






   
  <!-- start source code -->
   
    <source lang="java">
<HTML>
    <HEAD>
        <TITLE>Working With Constructors and Inheritance</TITLE>
    </HEAD>
    <BODY>
        <H1>Working With Constructors and Inheritance</H1>
        <%!
            javax.servlet.jsp.JspWriter localOut;
            
            class BaseClass
            {
                BaseClass() throws java.io.IOException 
                {
                    localOut.println("In a\"s constructor...<BR>");
                }
                BaseClass(String s)  throws java.io.IOException
                {
                    localOut.println("In a\"s String constructor...<BR>");
                    localOut.println(s);
                }
            }
            
            class DerivedClass extends BaseClass  
            {
                DerivedClass(String s) throws java.io.IOException 
                {
                    super(s);
                    localOut.println("In b\"s String constructor...<BR>");
                    localOut.println(s);
                }
            }
        %>     
        <%
            localOut = out;     
            DerivedClass obj = new DerivedClass("Hello from JSP!<BR>");
        %>
    </BODY>
</HTML></source>
    
   
  <!-- end source code -->