这个压缩包里的都是超级经典的java例子

				
				
				
				Creating a Custom Editing Command for a JTextComponent (Java Developers Almanac Example)
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				
				The Java Developers Almanac 1.4
				
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				    javax.swing.text
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				        Actions and Key Bindings
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				  e1002. Creating a Custom Editing Command for a JTextComponent
				
				This example demonstrates how to implement an editing command.
				There are two steps when creating a custom command.
				The first is to create an action object that executes the
				desired functionality and then installs the action object 
				in the component. The second is to bind a keystroke to the action
				object using an inputmap.
				
				 Text component actions should extend from TextAction.
				TextAction has a convenience method for finding the appropriate
				text component on which to operate.
				
				 This example implements a Lowercase command that converts
				characters to lowercase.  If the selection is empty, the command
				converts the character following the caret and then moves the caret
				forward one space.  If the selection is not empty, the command
				converts the characters in the selection.
				
				
				    JTextArea comp = new JTextArea();
				    
				    // Bind F2 to the lowercase action
				    String actionName = "Lowercase";
				    comp.getInputMap().put(KeyStroke.getKeyStroke("F2"), actionName);
				    
				    // Install the action
				    comp.getActionMap().put(actionName,
				        new TextAction(actionName) {
				            public void actionPerformed(ActionEvent evt) {
				                lowercaseSelection(getTextComponent(evt));
				            }
				        }
				    );
				    
				    public static void lowercaseSelection(JTextComponent comp) {
				        if (comp.getSelectionStart() == comp.getSelectionEnd()) {
				            // There is no selection, only a caret
				            if (comp.getCaretPosition() < comp.getDocument().getLength()) {
				                // The caret must be at least one position left of the end
				                try {
				                    int pos = comp.getCaretPosition();
				                    Document doc = comp.getDocument();
				                    String str = doc.getText(pos, 1).toLowerCase();
				    
				                    doc.remove(pos, 1);
				                    doc.insertString(pos, str, null);
				                    comp.moveCaretPosition(pos+1);
				                } catch (BadLocationException e) {
				                }
				            }
				        } else {
				            // There is a selection
				            int s = comp.getSelectionStart();
				            int e = comp.getSelectionEnd();
				    
				            comp.replaceSelection(comp.getSelectedText().toLowerCase());
				            comp.select(s, e);
				        }
				    }
				
				
				
				
				             Related Examples
				
				
				
				
				e1001. 
				    Overriding the Default Action of a JTextComponent
				
				
				
				e1003. 
				    Overriding a Few Default Typed Key Bindings in a JTextComponent
				
				
				
				e1004. 
				    Overriding Many Default Typed Key Bindings in a JTextComponent
				
				
				
				e1005. 
				    Listing the Key Bindings in a JTextComponent Keymap
				
				
				
				
				
				
				
				
				        See also: 
				
				    Caret and Selection
				  
				
				
				    Events
				  
				
				
				    JEditorPane
				  
				
				
				    JFormattedTextField
				  
				
				
				    JTextArea
				  
				
				
				    JTextComponent
				  
				
				
				    JTextField
				  
				
				
				    JTextPane
				  
				
				
				    Styles
				  
				
				
				
				
				
				
				
				
				
				© 2002 Addison-Wesley.