java文件处理之压缩,分割

http://blog.csdn.net/ycg01/article/details/1366648

 

java文件处理之压缩,分割

标签： javaexceptionimportnullbytefile

2006-11-05 00:30 1574人阅读 评论(1) 收藏 举报

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点滴（12） 

版权声明：本文为博主原创文章，未经博主允许不得转载。

一.简单文件压缩，解压

 

package cn.edu.nju.vicken;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.InputStream;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.Enumeration;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipOutputStream;

/**
 * 
 * @author VickenYang
 * 文件处理工具
 */
public class FileProcessor {
    
    public static void createZipFile(File from,File to) throws Exception {
        if(!from.isFile()){
            throw new Exception("file not exists"+from.getAbsolutePath());
        }
        if(to.isFile()){
            throw new Exception("file already exists"+to.getAbsolutePath());
        }
        else{
            to.createNewFile();
        }
        
        ZipOutputStream zos = new ZipOutputStream(new FileOutputStream(to));
        ZipEntry ze = null;
        byte[] buf = new byte[1024];
        int readLen = 0;
        ze = new ZipEntry(from.getAbsolutePath());
        ze.setSize(from.length());
        ze.setTime(from.lastModified());
        zos.putNextEntry(ze);
        InputStream is = new BufferedInputStream(new FileInputStream(from));
        while ((readLen=is.read(buf, 0, 1024))!=-1) {
            zos.write(buf, 0, readLen);
        }
        is.close();
        zos.close();
    }
    
    public static void decompressZipFile(File from,File to) throws Exception{
        if(!from.isFile()){
            throw new Exception("file not exists"+from.getAbsolutePath());
        }
        if(!to.isDirectory()){
            throw new Exception("file not directory"+to.getAbsolutePath());
        }
        ZipFile zfile = new ZipFile(from.getAbsoluteFile());
        Enumeration zList = zfile.entries();
        ZipEntry ze=null;
        byte[] buf=new byte[1024];
        while(zList.hasMoreElements()){
            ze=(ZipEntry)zList.nextElement();
            if(ze.isDirectory()){
                continue;
            }
            String[] zet = ze.getName().replace('/', '/').split("/");
            OutputStream os=new BufferedOutputStream(new FileOutputStream(to.getAbsoluteFile()+zet[zet.length-1]));
            InputStream is=new BufferedInputStream(zfile.getInputStream(ze));
            int readLen=0;
            while ((readLen=is.read(buf, 0, 1024))!=-1) {
                os.write(buf, 0, readLen);
            }
            is.close();
            os.close();
        }
        zfile.close();
    }
}

 二.定时器程序

 

import java.util.Timer;
import java.util.TimerTask;
class MyTask extends TimerTask{
    String name;
    public MyTask(String name){
        this.name = name;
    }
    public void run(){
        System.out.println(name);
    }
}
public class TestTask {
    public static void main(String[] args) {
        // TODO Auto-generated method stub
        TimerTask task = new MyTask("10秒执行一次");
        java.util.Date today = new java.util.Date();
        //开始时间设置为昨天
        java.util.Date beginTime = new java.util.Date(today.getYear(),today.getMonth(),today.getDate()-1,22,0,0);
        //10秒一次
        new Timer().schedule(task,beginTime,1000*10);
        //执行一次
        task = new MyTask("只执行一次");
        new Timer().schedule(task,beginTime);
    }
}

 

三.分割，合并文件

 

//拆分文件
    public static void splitFile(File file,int size) throws Exception{
        if(size<=0){
            size = 1024;
        }
        if(!file.isFile()){
            throw new Exception("file not exists"+file.getAbsolutePath());
        }
        String filename = file.getAbsolutePath();
        File filetmp = new File(filename+"_"+0+".vk");
        if(filetmp.isFile()){
            throw new Exception("file exists"+filetmp.getAbsolutePath());
        }
        
        byte[] buf = new byte[1024*10];
        FileInputStream fis = new FileInputStream(file);
        int readsize = 0;
        int pos = 0;
        int k = 0;
        int m = -1;
        File fileout = null;
        FileOutputStream fos = null;
        while((readsize = fis.read(buf, 0, buf.length))>0){
            
            if(k!=m)
            {
                if(fos!=null){
                    fos.close();
                    fos = null;
                }
                m = k;
                fileout = new File(filename+"_"+k+".vk");
                fos = new FileOutputStream(fileout);
            }
            fos.write(buf,0,readsize);
            fos.flush();
            pos += readsize;
            if(pos>size*(k+1)){
                k++;
            }
        }
        if(fos!=null){
            fos.close();
            fos = null;
        }
        fis.close();
    }
    
    
    //合并文件
    public static void combination(File file) throws Exception{
        String filename = file.getAbsolutePath();
        File fileout = new File(filename);
        
        if(fileout.isFile()){
            throw new Exception("file exists"+fileout.getAbsolutePath());
        }
        FileOutputStream fos = new FileOutputStream(fileout);
        int k = 0;
        File filein = null;
        FileInputStream fis = null;
        byte[] buf = new byte[1024*10];
        while(true){
            if(fis!=null){
                fis.close();
                fis = null;
            }
            filein = new File(filename+"_"+k+".vk");
            if(!filein.isFile()){
                break;
            }
            fis = new FileInputStream(filein);
            int readsize = 0;
            while((readsize = fis.read(buf, 0, buf.length))>0){
                fos.write(buf,0,readsize);
                fos.flush();
            }
            k++;
        }
        if(fis!=null){
            fis.close();
            fis = null;
        }
        fos.close();
    }