利用数据流实现复制文件

2019-11-10 22:08:31

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package com.mashensoft;import java.io.BufferedInputStream;import java.io.BufferedOutputStream;import java.io.BufferedWriter;import java.io.ByteArrayInputStream;import java.io.File;import java.io.FileFilter;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.InputStream;import java.io.InputStreamReader;import java.io.OutputStreamWriter;import java.io.PRintWriter;import java.io.Reader;import java.io.Writer;import java.util.Scanner;/** * 读取文本文件，读取图片，读取视频 * * @author PeicongHe * */public class Homework { /** * 实现复制文件运用FileInputStream,FileOutputStream对文件进行读取写入只能一个一个字符复制（速度慢） */ public static void copyFile(String sourceName, String dest) { // 1:读取一个文件 // 2:写入一个文件 try { FileInputStream fis = new FileInputStream(sourceName);// 源文件地址 FileOutputStream fos = new FileOutputStream(dest);// 目的文件地址 int a = 0; while ((a = fis.read()) != -1) { fos.write(a); } fos.flush(); fos.close(); fis.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test2 * 实现复制文件（提速）运用FileInputStream,FileOutputStream对文件进行读取写入引用数组byte[] 缺点： * 当使用数组的时候，如果文件里的字符的长度不是数组的倍数的时候，拿到的数据会重复 */ public static void test2() { byte[] myArray = new byte[3]; try { InputStream fis = new FileInputStream("src/a.txx"); while (fis.read(myArray) != -1) { // 如果达到文件尾，跳出循环 for (int i = 0; i < myArray.length; i++) { System.out.print((char) myArray[i]); } } fis.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test3 * 实现复制文件（提速）（改进）运用FileInputStream,FileOutputStream对文件进行读取写入引用数组byte[] 缺点： * 当文件的内容是中的时候会出现乱码 */ public static void test3() { byte[] myArray = new byte[3]; int len;// 长度 try { FileInputStream is = new FileInputStream("src/a.txt"); while ((len = is.read(myArray)) != -1) { // 定义一个新的数组，防止有多余的数据 for (int i = 0; i < len; i++) { System.out.print((char) myArray[i]); } } is.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test4 * 实现复制文件（速度快）运用FileInputStream,FileOutputStream对文件进行读取写入只能一个一个字符复制（速度快） * write */ public static void test4() { byte[] myArray = new byte[32]; int len; try { InputStream is = new FileInputStream("src/BangBang.flac"); FileOutputStream os = new FileOutputStream("src/BangBangx.flac"); // 如果到达文件尾，无法满足while的条件，不会执行while语句的内容 while ((len = is.read(myArray)) != -1) { // 定义一个新的数组，防止有多余的数据 byte descArray[] = new byte[len]; for (int i = 0; i < len; i++) { descArray[i] = myArray[i]; } os.write(descArray); } is.close(); os.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test5 * 实现复制文件（速度快）(jdk) */ public static void test4x(String sourceName, String targetName) { byte myArray[] = new byte[1024]; int len; try { InputStream fis = new FileInputStream(sourceName); FileOutputStream fos = new FileOutputStream(targetName); while ((len = fis.read(myArray)) != -1) { /** * os.write JDK系统是已经直接封装好的，可以直接用，速度会更快一些 os.write(数字长度，起始，末尾) */ fos.write(myArray, 0, len); } fis.close(); fos.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } public static void test4xx() { try { FileInputStream fis = new FileInputStream("src/a.txt"); FileOutputStream fos = new FileOutputStream("src/axx.txt"); int len; byte[] myArray = new byte[1024]; while ((len = fis.read(myArray)) != -1) { fos.write(myArray, 0, len); } fis.close(); fos.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } System.out.println("执行成功"); } /** * test6 * 使用缓冲区，提高速率 * 用到FileInputStream,FileOutputStream,BufferedInputStream,BufferedOutputStream * 用缓冲区的好处 * 没有缓存区，那么每read一次，就会发送一次IO操作；有缓存区，第一次read时，会一下读取x个字节放入缓存区，然后后续的read都会从缓存中读取，当read到缓存区末尾时，会再次读取x个字节放入缓存区。很明显，第二种方式，会减少IO操作，效率更高，缺点就是，内存占用的多。 */ public static void test6() { InputStream is; try { is = new FileInputStream("src/BangBang.flac"); FileOutputStream os = new FileOutputStream("src/BangBangxx.flac"); BufferedInputStream bis = new BufferedInputStream(is); BufferedOutputStream bos = new BufferedOutputStream(os); byte myArrat[] = new byte[1024]; int len; while ((len = bis.read(myArrat)) != -1) { bos.write(myArrat, 0, len); } bos.flush(); bis.close(); bos.close(); os.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test8 * 当我们没有文件的时候，如何使用流 * 这里用到的是字节数组输出流和字节数组输入流 * ByteArrayOutputStream类是在创建它的实例时，程序内部创建一个byte型别数组的缓冲区，然后利用ByteArrayOutputStream和ByteArrayInputStream的实例向数组中写入或读出byte型数据。在网络传输中我们往往要传输很多变量，我们可以利用ByteArrayOutputStream把所有的变量收集到一起，然后一次性把数据发送出去。 */ public static void test8() { String content = "hepeicongshidashuaige"; ByteArrayInputStream is = new ByteArrayInputStream(content.getBytes()); int a = 0; byte[] myArray = new byte[3]; try { while ((a = is.read(myArray)) != -1) { for(int i=0;i<a;i++){ System.out.print((char)myArray[i]); } } } catch (IOException e) { e.printStackTrace(); } } /** * test9 * 问题：当有中文的时候，可能会出现乱码 */ public static void test9() { String content = "你"; byte myArray[] = content.getBytes(); for(int i = 0;i<myArray.length;i++){ System.out.println((char)myArray[i]); } } /** * test10 * 问题：当有中文的时候，可能出现乱码，当有了流的时候 * 出现乱码的原因是：字符的是字节是2个长度，而read（byte[]）以一个字节扫描。将字符的两个字节拆分开了，所以出现乱码 */ public static void test10() { String content = "你"; ByteArrayInputStream is = new ByteArrayInputStream(content.getBytes()); byte a = 0; while ((a = (byte) is.read()) != -1) { System.out.print((char) a); } } /** * test11 * 解决方法：利用数组Array[2],和ByteArrayInputeStream，ByteArrayOutputStream，将字符的数据存储在一起（以二的倍数存储）最后一起输出就可以避免出现乱码 */ public static void test11() { String content = "你"; ByteArrayInputStream bis = new ByteArrayInputStream(content.getBytes()); byte a[] = new byte[2]; try { bis.read(a); System.out.println(new String(a)); } catch (IOException e) { e.printStackTrace(); } } /** * text12 * 同理输出一串中文 */ public static void test12() { String content = "杨晓怡"; ByteArrayInputStream bis = new ByteArrayInputStream(content.getBytes()); byte a[] = new byte[2]; int len; try { while((len=bis.read(a))!=-1){ for(int i=0;i<len-1;i++){ System.out.println(new String(a)); } } } catch (IOException e) { e.printStackTrace(); } } public static void test12x() { try { FileInputStream is = new FileInputStream("src/a.txt"); byte myArray[] = new byte[2]; int a = 0; try { while ((a = is.read(myArray)) != -1) { System.out.println(new String(myArray)); } } catch (IOException e) { e.printStackTrace(); } } catch (FileNotFoundException e) { e.printStackTrace(); } } /** * test13 * 引用字符流解决中文问题 Reader 抽象类，InputStreamReader实现类 * 只能输出一个中文(一个字符) */ public static void test13() { try { Reader reader = new InputStreamReader(new FileInputStream("src/a.txt")); int a = reader.read(); System.out.print((char)a); reader.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test14 * 引用字符流解决中文的问题 Reader抽象类，InputStreamReader实现类读取到的数组中，一次可以读取多个字符 * */ public static void test14() { Reader reader; try { reader = new InputStreamReader(new FileInputStream("src/a.txt")); char myArray[] = new char[3]; int a = 0; while ((a = reader.read(myArray)) != -1) { System.out.println(new String(myArray)); } reader.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test15 * 用字符流写入数据到文件里 * 这里用到Writer,OutputStreamWriter，FileOutputStream */ public static void test15() { try { Writer writer = new OutputStreamWriter(new FileOutputStream("src/a.txt", true)); //指向操作对象 //true表示可以在文件的原有内用上写入内容 writer.write("jiajia"); writer.flush(); writer.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } System.out.println("写入成功"); } /** * test16 * 复制文件 * 利用Reader,Writer,InputStreamReader,OutputStreamReader */ public static void test15x() { try { Reader reader = new InputStreamReader(new FileInputStream("src/a.txt")); Writer writer = new OutputStreamWriter(new FileOutputStream("src/a15x.txt")); char myArray[] = new char[3]; int a = 0;//长度 while ((a = reader.read(myArray)) != -1) { System.out.println(new String(myArray)); writer.write(myArray); } writer.flush(); reader.close(); writer.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } System.out.println("复制成功"); } public static void test15xx(){ try { Reader reader = new InputStreamReader(new FileInputStream("src/a.txt")); Writer writer = new OutputStreamWriter(new FileOutputStream("src/axxx.txt")); char[] myArray=new char[32]; int len; while((len=reader.read(myArray))!=-1){ System.out.println(new String(myArray)); writer.write(myArray); } } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * 利用缓冲，使写入字符流更高效 * 用到BufferedWriter * BufferedWriter(new OutputStreamWriter(new FileOutputStream(where))) */ public static void test17() { try { BufferedWriter bw = new BufferedWriter(new OutputStreamWriter(new FileOutputStream("src/d.txt"))); bw.write("hello,何沛聪"); bw.flush(); bw.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } } /** * test18 * 为了能够写入数据的时候更加方便，我们要引入printWriter * 用到PrintWriter */ public static void test18() { try { PrintWriter pw = new PrintWriter("src/e.txt"); pw.print("回车/n"); pw.print("新行/r"); pw.print(18); pw.flush(); pw.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } System.out.println("执行成功"); } /** * 读取文件的时候更加简单 scanner */ public static void test19() { Scanner sc; try { sc = new Scanner(new FileInputStream("src/a15x.txt")); while (sc.hasNextLine()) { System.out.println(sc.nextLine()); } } catch (FileNotFoundException e) { e.printStackTrace(); } } /** * 复制利用print - sanner */ public static void test19x() { try { Scanner sc=new Scanner(new FileInputStream("src/a.txt")); PrintWriter pw = new PrintWriter("src/acp.txt"); while(sc.hasNextLine()){// System.out.println(sc.nextLine()); pw.print(sc.nextLine()); } sc.close(); pw.close(); } catch (FileNotFoundException e) { e.printStackTrace(); } System.out.println("执行成功"); } /** * 复制利用BufferedWriter - Scanner */ public static void test19xx(){ try { Scanner sc=new Scanner(new FileInputStream("src/a.txt")); BufferedWriter bfw=new BufferedWriter(new OutputStreamWriter(new FileOutputStream("src/acpx.txt"))); while(sc.hasNextLine()){ bfw.write(sc.nextLine()); } //将缓存区的数据强制写入到目标文件 bfw.flush(); bfw.close(); sc.close(); System.out.println("执行成功"); } catch (FileNotFoundException e) { e.printStackTrace(); } catch (IOException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public static void main(String[] args) { long a = System.currentTimeMillis(); // copyFile("a.txt","b.txt"); // test4(); // test4x("BangBang.flac","BangBangtx.flac"); test19xx(); System.out.println("/r<br>执行耗时 : " + (System.currentTimeMillis() - a) / 1000f + " 秒 "); }}

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