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("nn--------------------------------------------------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("nn--------------------------------------------------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(); } }
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