java实现文件读写与压缩实例

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();  }}