nio文件读写

FileUtil .java

import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.nio.ByteBuffer;
import java.nio.MappedByteBuffer;
import java.nio.channels.FileChannel;



/** *//**
 * @author lichun
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class FileUtil ...{
    
    public static ByteBuffer readFile(String filename) throws Exception
    ...{
        FileChannel fiChannel = new FileInputStream(filename).getChannel();
        MappedByteBuffer mBuf;
        mBuf = fiChannel.map(FileChannel.MapMode.READ_ONLY, 0, fiChannel.size());
        fiChannel.close();
        fiChannel = null;
        
        return mBuf;      
        
    }
    
    
    public static void saveFile(ByteBuffer src, String filename) throws Exception
    ...{
        FileChannel foChannel = new FileOutputStream(filename).getChannel();
        foChannel.write(src);
        foChannel.close();  
        foChannel = null; 
    }
    
    public static void saveFile(FileChannel fiChannel, String filename) throws IOException
    ...{
        MappedByteBuffer mBuf;
        mBuf = fiChannel.map(FileChannel.MapMode.READ_ONLY, 0, fiChannel.size());

        FileChannel foChannel = new FileOutputStream(filename).getChannel();
        foChannel.write(mBuf);
        
        fiChannel.close();
        foChannel.close(); 
        
        fiChannel = null;
        foChannel = null; 
    }
    

    public static void main(String[] args) throws Exception 
    ...{     
        final String suffix = ".txt";
        final String filename = "bufferTemp";
        final String srcFile =  filename + suffix ;
        final String backupFile = filename + "-" + System.currentTimeMillis() + suffix;
        ByteBuffer byteBuffer = FileUtil.readFile(srcFile);
        FileUtil.saveFile(byteBuffer, backupFile);
        byteBuffer = null;
        
    }
}

TransferFile.java

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.nio.ByteBuffer;
import java.nio.channels.FileChannel;
import java.util.*;


/** *//**
 * @author lichun
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class TransferFile ...{
    
    private String srcFile;
    
    List files = new ArrayList();
    ByteBuffer byteBuffer;
   
    public TransferFile()
    ...{
        createFileNames();
    }
    
    private void createFileNames()
    ...{
        for (int i = 0; i < 10; i++)
        ...{
            files.add(i + "");
        }
    }  
    
    public List getFiles()
    ...{
        return this.files;
    }

    public String getSrcFile() ...{
        return srcFile;
    }

    public void setSrcFile(String srcFile) ...{
        this.srcFile = srcFile;
    }
    
    public void saveFiles() throws FileNotFoundException
    ...{
        String tempFile;
        for (int i = 0; i < this.files.size(); i++) 
        ...{
            tempFile = "test-files/" + (String)files.get(i) + ".txt";
            System.out.println("begin create thread for " + tempFile);
            
            FileChannel fiChannel = new FileInputStream(this.srcFile).getChannel();
            
            WriteFileThread writeFileThread = new WriteFileThread("writeFile", fiChannel, tempFile);
            writeFileThread.start();   
        }
        
    }

    public static void main(String[] args) throws Exception 
    ...{
        final String srcFile = "test-files/transferFile.txt";
        TransferFile transferFile = new TransferFile();
        transferFile.setSrcFile(srcFile);
        transferFile.saveFiles();        
    }
}

WriteFileThread.java

import java.nio.channels.FileChannel;

/** *//**
 * @author lichun
 *
 * TODO To change the template for this generated type comment go to
 * Window - Preferences - Java - Code Style - Code Templates
 */
public class WriteFileThread extends Thread ...{

    private FileChannel fiChannel;
    private String fileName;
   
    public WriteFileThread(String name)
    ...{
        super(name);
    }
    
    public WriteFileThread(String name, FileChannel fiChannel, String fileName)
    ...{
        this(name);
        this.fiChannel = fiChannel;
        this.fileName = fileName;
    }
    
    public void setFiChannel(FileChannel fiChannel)
    ...{
        this.fiChannel = fiChannel;
    }
    
    public FileChannel getFiChannel() ...{
        return fiChannel;
    }
  
    public void setFileName(String fileName) ...{
        this.fileName = fileName;
    }
    
    public String getFileName() ...{
        return fileName;
    }
    
    public void run()
    ...{
        System.out.println("in Thread: " + this.getName());
        try ...{
            FileUtil.saveFile(this.fiChannel, this.fileName);
        } catch (Exception e) ...{
            System.out.println("The file is not founded: " + fileName);
            e.printStackTrace();
        }
        System.out.println("end Thread: " + this.getName());
    }
}