Java学习 IO流 作业02

 1.将前面作业中关于文件拷贝的操作，替换为高效流

package work;
/*
 * 1.将前面作业中关于文件拷贝的操作，替换为高效流
 */
import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class Work01 {
	public static void main(String[] args) throws IOException{
		File file = new File("C:\\Users\\ZYX'sDay\\Desktop\\FileDemo");
		File file1 = new File(file,"ss");
		File file2 = new File(file,"sfsdf");
		
		fileCopy(file1,file2);
	}

	private static void fileCopy(File file1, File file2) throws IOException{
		FileInputStream fis = null;
		FileOutputStream fos = null;
		
		File[] files = file1.listFiles();
		for (File file : files) {
			if(file.isDirectory()){
				fileCopy(file, file2);
			}else {
				//转换高效 缓冲流
				fis = new FileInputStream(file);
				BufferedInputStream bis = new BufferedInputStream(fis);
				
				fos = new FileOutputStream(new File( file2, file.getName() ) );
				BufferedOutputStream bos = new BufferedOutputStream(fos);
				
				byte[] bytes = new byte[1024];
				int len = 0;
				
				while( (len = bis.read(bytes)) != -1 ){
					bos.write(bytes, 0, len);
				}
				bis.close();
				bos.close();
			}
		}
		
	}

}

 2. 用代码实现以下需求
    (1)有如下字符串"If you want to change your fate I think you must come to the dark horse to learn java"(用空格间隔)
    (2)打印格式：
        to=3
        think=1
        you=2
        //........
    (3)按照上面的打印格式将内容写入到D:\\count.txt文件中(要求用高效流)

package work;

import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.util.Arrays;
import java.util.HashMap;

/*
 * 2. 用代码实现以下需求
	(1)有如下字符串"If you want to change your fate I think you must come to the dark horse to learn java"(用空格间隔)
	(2)打印格式：
		to=3
		think=1
		you=2
		//........
	(3)按照上面的打印格式将内容写入到D:\\count.txt文件中(要求用高效流)
 */
public class Work02 {
	public static void main(String[] args) throws IOException{
		String str = "If you want to change your fate I think you must come to the dark horse to learn java";
		FileWriter fw = new FileWriter("D:\\day23worktest\\buffer\\count.txt");
		BufferedWriter bw = new BufferedWriter(fw);
		//用正则表达式拆分字符串 空格为标志
		String[] strings = str.split(" ");
		HashMap<String, Integer> hMap = new HashMap<>();
		Object[] key_arr = null;
		
		//双层循环 遍历匹配
		for (int i = 0; i < strings.length-1; i++) {
			int count = 0;
			for(int j = 1 ; j < strings.length-1 ;j++){
				if( strings[i].equals(strings[j]) ){
					count++;
				}
			}
			hMap.put(strings[i], count);
		}
		
		//整理顺序
		key_arr = hMap.keySet().toArray();
		Arrays.sort(key_arr);
		
		for(Object key : key_arr){
			bw.append(key.toString());
			bw.append('=');
			bw.append(hMap.get(key).toString());
			bw.newLine();
			bw.flush();
		}
		bw.close();
	}

}

 3.利用转换流将GBK格式文件以UTF-8输出

package work;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStreamWriter;

//3.利用转换流将GBK格式文件以UTF-8输出
public class Work03 {
	public static void main(String[] args) throws IOException{
		File file = new File("C:\\Users\\ZYX'sDay\\Desktop\\FileDemo");
		File file1 = new File(file, "GBK.txt");
		File file2 = new File(file,"utfs8.txt");
		FileInputStream fis = new FileInputStream(file1);
		FileOutputStream fos = new FileOutputStream(file2);
		//创建转换流
		InputStreamReader isr = new InputStreamReader(fis, "GBK");
		OutputStreamWriter osw = new OutputStreamWriter(fos,"utf-8");
		
		char[] ch = new char[1024];
		int len = isr.read(ch);
		System.out.println(new String(ch,0,len));
		osw.write(ch, 0, len);
		isr.close();
		osw.close();
	}

}

 4.java写一个程序，实现从文件中读出文件内容，并将其打印在屏幕当中，并标注上行号

package work;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileReader;
import java.io.IOException;
import java.io.LineNumberReader;

//4.java写一个程序，实现从文件中读出文件内容，
//并将其打印在屏幕当中，并标注上行号
public class Work04 {
	public static void main(String[] args) throws IOException{
		File file = new File("D:\\day23worktest\\buffer\\count.txt");
		FileReader fr = new FileReader(file);
		BufferedReader br = new BufferedReader(fr);
		//建读行方法
		LineNumberReader lnr = new LineNumberReader(br);
		
		String line = null;
		while( (line = lnr.readLine()) != null ){
			System.out.println(lnr.getLineNumber()+". "+line);
		}
		br.close();
	}

}