Java实现目录查找与文本阅读

1.实现文本阅读

package AllAboutFile;

/**

*

* @author lucifer

*/

import java.awt.*;

import java.awt.event.*;

import java.io.*;

public class FileViewer extends Frame implements ActionListener{

String directory;

TextArea textarea; //显示文本内容的地方

public FileViewer(){

this(null,null);

}

public FileViewer(String filename){

this(null,filename);

}

public FileViewer(String directory,String filename){

super();

addWindowListener(

new WindowAdapter(){

public void WindowClosing(WindowEvent e){

dispose();

}

}

);

//Create TextArea

textarea = new TextArea("",24,80);

textarea.setFont(new Font("Monospaced",Font.PLAIN,12));

textarea.setEditable( false );

this.add("Center",textarea);

//Create Panel

Panel p = new Panel();

p.setLayout( new FlowLayout(FlowLayout.RIGHT,10,5) );

this.add(p,"South");

//Create Button

Font font = new Font("SansSerif",Font.BOLD,14);

Button OpenFile = new Button("Open File");

Button Close = new Button("Close");

OpenFile.addActionListener(this);

OpenFile.setActionCommand("open");

OpenFile.setFont(font);

Close.addActionListener( this );

Close.setActionCommand( "close" );

Close.setFont( font );

p.add( OpenFile );

p.add( Close );

this.pack();

if(directory == null){

File f;

if((filename != null)&&(f = new File(filename)).isAbsolute()){

directory = f.getParent();

filename = f.getName();

}

else

directory = System.getProperty( "user.dir" );

}

this.directory = directory;

setFile(directory,filename);

}

public void setFile(String directory,String filename){

if((filename == null)||(filename.length() == 0)){

return;

}

File f = new File(directory,filename);

try{

FileReader fr = new FileReader(f);

char buffer[] = new char[4096];

int len;

textarea.setText( "" );

//show text

while((len = fr.read(buffer)) != -1){

String str = new String(buffer,0,len);

textarea.append( str );

}

this.setTitle( "FileViewer:" + filename );

textarea.setCaretPosition( 0 );

fr.close();

}

catch(Exception e){

textarea.setText( e.getMessage() );

}

}

public void actionPerformed(ActionEvent e){

String cmd = e.getActionCommand();

if(cmd.equals( "open" )){

FileDialog fd = new FileDialog(this,"Select File",FileDialog.LOAD);

fd.setDirectory( directory );

fd.show();

directory = fd.getDirectory();

setFile(directory,fd.getFile());

fd.dispose();

}

else if(cmd.equals( "close" )){

this.dispose();

}

}

static public void main(String[] args){

Frame f = new FileViewer((args.length==1)?args[0]:null);

f.addWindowListener(new WindowAdapter(){

public void WindowClosed(WindowEvent e){

System.exit(0);

}

}

);

f.show();

}

}

2.目录显示与操作

package AllAboutFile;

/**

*

* @author lucifer

*/

import java.awt.*;

import java.awt.event.*;

import java.io.*;

import java.text.DateFormat;

public class FileLister extends Frame implements ActionListener,ItemListener{

private List list;

private TextField details;

private Panel buttons;

private Button up,close;

private File currentDir;

private FilenameFilter filter;

private String[] files;

private DateFormat dateFormatter =

DateFormat.getDateTimeInstance(DateFormat.SHORT,DateFormat.SHORT);

public FileLister(String directory,FilenameFilter filter){

super("File Lister");

this.filter = filter;

addWindowListener(new WindowAdapter(){

@Override

public void windowClosing(WindowEvent e){

dispose();

}

});

list = new List(12,false);

list.setFont( new Font("MonoSpaced",Font.PLAIN,14) );

list.addActionListener( this );

list.addItemListener( this );

details = new TextField();

details.setFont( new Font("MonoSpaced",Font.PLAIN,12) );

details.setEditable(false);

buttons = new Panel();

buttons.setLayout(new FlowLayout(FlowLayout.RIGHT,15,5));

buttons.setFont( new Font("SansSerif",Font.BOLD,14) );

up = new Button("Upper Directory");

close = new Button("Close");

up.addActionListener( this );

close.addActionListener( this );

buttons.add( up );

buttons.add( close );

this.add( list, "Center" );

this.add( details, "North" );

this.add( buttons , "South" );

this.setSize( 500 , 350);

listDirectory(directory);

}

public void listDirectory(String directory){

File dir = new File(directory);

if(!dir.isDirectory())

throw new IllegalArgumentException("FileListener : no such firectory");

files = dir.list( filter );

java.util.Arrays.sort( files );

list.removeAll();

list.add( "[Up to Parent Directory]" );

for(int i = 0;i < files.length; i++){

list.add( files[i] );

}

this.setTitle( directory );

details.setText( directory );

currentDir = dir;

}

public void actionPerformed(ActionEvent ae){

if(ae.getSource() == close)

this.dispose();

else if(ae.getSource() == up)

up();

else if(ae.getSource() == list){

int i = list.getSelectedIndex();

if( i == 0 )

up();

else{

String name = files[i-1];

File f = new File(currentDir,name);

String fullname = f.getAbsolutePath();

if(f.isDirectory())

listDirectory(fullname);

else new FileViewer(fullname).show();

}

}

}

public void itemStateChanged(ItemEvent ie){

int i = list.getSelectedIndex() - 1;

if(i < 0)

return;

String filename = files[i];

File f = new File(currentDir,filename);

if(!f.exists())

throw new IllegalArgumentException("FileLister : no such file or directory");

String info = null;

if(f.isDirectory())

info += File.separator;

info += " " + f.length() + " bytes ";

info += dateFormatter.format( new java.util.Date(f.lastModified()) );

if(f.canRead())

info += " Read";

if(f.canWrite())

info += " Write";

details.setText(info);

}

protected void up(){

String parent = currentDir.getParent();

if(parent == null)

return;

listDirectory(parent);

}

public static void usage(){

System.out.println("Usage : java FileLister [directory_name] " +

"[-e file_extension]");

System.exit( 0 );

}

public static void main(String[] args){

FileLister f;

FilenameFilter filter = null;

String directory = null;

for(int i = 0;i < args.length; i++){

if(args[i].equals("-e")){

if(++i > args.length)

usage();

final String suffix = args[i];

filter = new FilenameFilter(){

public boolean accept(File dir,String name){

if(name.endsWith( suffix ))

return true;

else

return (new File(dir,name)).isDirectory();

}

};

}

else{

if(directory != null)

usage();

else directory = args[i];

}

}

if(directory == null)

directory = System.getProperty( "user.dir" );

f = new FileLister(directory,filter);

f.addWindowListener(new WindowAdapter(){

@Override

public void windowClosed(WindowEvent e){

System.exit(0);

}

});

f.show();

}

}