java实现文件读写与压缩实例

本文通过实例讲述了java对文件读写与压缩的实现方法，具体代码如下：

package com.toone.iform.action.common;

import java.io.bufferedreader; 
import java.io.bufferedwriter; 
import java.io.file; 
import java.io.fileinputstream; 
import java.io.filenotfoundexception; 
import java.io.fileoutputstream; 
import java.io.filereader; 
import java.io.filewriter; 
import java.io.ioexception; 
import java.io.inputstream; 
import java.util.enumeration; 
import java.util.random; 
import java.util.zip.zipentry; 
import java.util.zip.zipexception; 
import java.util.zip.zipfile;
public class testfileio {
  static string s = file.separator;
 
  private static void testinput() {
    // d盘下有个welcome.java文件，现在按字节读入：     
   int a = 0;
    // int counter=0;     
   fileinputstream f11;
    // 输入流     
   try {
      f11 = new fileinputstream("d:" + s + "welcome.java");
      while ((a = f11.read()) != -1)
        system.out.print((char) a); // 这里是按字节输出，中文字符无法正常输出，因为一个中文字符时两个字节。       
       system.out.println("\n\n--------------------------------------------------\n");
 
      filereader f12 = new filereader("d:" + s + "welcome.java");
      while ((a = f12.read()) != -1)
        system.out.print((char) a);// 这里是按字符输出，中文字符都可以正常输出      
       system.out.println("\n\n--------------------------------------------------\n");
 
      f11.close();// 读完之后要关闭文件      
      f12.close();// 读完之后要关闭文件    
      } catch (filenotfoundexception e) {
      // todo auto-generated catch block       
       e.printstacktrace();
    } catch (ioexception e) {
      // todo auto-generated catch block      
     e.printstacktrace();
    }
  }
 
  private static void testoutput() {
    // d盘下有个welcome.java文件，现在按字节读入：    
   int a = 0;
    // 输出流     
   file f21 = new file("d:" + s + "testfile" + s + "test1.txt");
   // 定义一个新的文件f21，然后判断在这一目录下是否存在，如果不存在，则创建之。    
   if (!f21.exists()) {
      f21.getparentfile().mkdirs();
      try {
        f21.createnewfile();
        // 将“welcome.java”的内容复制到f21         
        fileoutputstream fos = new fileoutputstream(f21);
        fileinputstream fis = new fileinputstream("d:" + s + "welcome.java");// 读入“welcome.java”文件         
        while ((a = fis.read()) != -1)
          fos.write(a);// 将读入的内存写到fos中，现在得到的test1.txt就是复制welcome.java的
        // writer类        
        filewriter f22 = new filewriter("d:" + s + "testfile" + s + "test2.txt");
        for (int i = 0; i < 65535; i++)
          f22.write(i);//写入到test2.txt中。由这里也可以看出，上面35-38行判断文件是否存在的语句也可以不要。         
        // 向文件中写入字符串         
        filewriter f23 = new filewriter("d:" + s + "testfile" + s + "test3.txt");
        f23.write("hello, world!");
 
        fos.close();
        fis.close();
        f22.close();
        f23.close();
      } catch (ioexception e) {
        // todo auto-generated catch block
         e.printstacktrace();
      }
    }
  }
 
  private static void testbufferring() {
    // d盘下有个welcome.java文件，现在按字节读入：     
   int a = 0, counter = 0;
    // 缓冲字符，实现高效写入     
   // bufferedwriter f31=new bufferedwriter(newfilewriter("d"+s+"testfile"+s+"test4.txt"));    
   bufferedwriter f31;
    try {
      f31 = new bufferedwriter(new filewriter("d:" + s + "testfile" + s
          + "test4.txt"));
      for (int i = 1; i <= 100; i++) {
        f31.write(string.valueof(new random().nextint(100)) + " ");
        if (i % 10 == 0)
          f31.newline();
      }
      f31.flush();// 刷新缓冲      
      f31.close();
 
      bufferedreader f32 = new bufferedreader(new filereader("d:" + s
          + "testfile" + s + "test4.txt"));
      string s32;
      system.out.println("输出文件f32的内容：");
      while ((s32 = f32.readline()) != null)
        system.out.println(s32);
      f32.close();
      system.out.println("\n--------------------------------------------------\n");
    } catch (ioexception e) {
      // todo auto-generated catch block       
     e.printstacktrace();
    }
  }
 
  private static void testzip() {
    try {
      file f1 = new file("d:/test.zip");
      file f2 = new file("d:/testfile/testzip");
      zipfile zf = new zipfile(f1);
      testziptounzip(zf, f2);
 
    } catch (ioexception e) {
      // todo auto-generated catch block
       e.printstacktrace();
    }
  }
 
  // 将压缩包zipfile解压到file中  
  public static void testziptounzip(zipfile zipfile, file file) {
    zipentry zentry = null;
    file zipout;
    inputstream zis = null;
    fileoutputstream fos = null;
    enumeration e = zipfile.entries();// zipfile的目录
    while (e.hasmoreelements()) {
      zentry = (zipentry) e.nextelement();
      system.out.println(zentry.getname());// zipfile下有哪些文件？可是为什么不按顺序输出？？
      // 将解压后的文件放到file文件夹下：      
      zipout = new file(file + s + zentry.getname());
 
      if (!zentry.isdirectory()) {
        try {
          zis = zipfile.getinputstream(zentry);
          if (!zipout.exists())
            zipout.getparentfile().mkdirs();
          fos = new fileoutputstream(zipout);
          byte[] b = new byte[1024];
          int length;
          while ((length = zis.read(b)) > 0) {
            fos.write(b, 0, length);
          }
          fos.close();
          zis.close();
        } catch (zipexception e1) {
          // todo auto-generated catch block           
         e1.printstacktrace();
        } catch (ioexception e1) {
          // todo auto-generated catch block          
         e1.printstacktrace();
        }
      }
    }
  }
 
  public static void main(string[] args) throws zipexception {
    // todo auto-generated method stub
    testinput();
    testoutput();
    testbufferring();
    testzip();
  }
}