这段时间在牛客上做题发现了很多有意思的题，这一篇主要来实现IO流的有关程序题。

• 遍历输出指定路径下的所有文件
  1.定义一个工具类，该类要求用户运行时输入一个路径。该工具类会将该路径下（及其子目录）的所有文件列出来。

import java.io.File;
import java.util.Scanner;

import com.sun.org.apache.bcel.internal.generic.F2D;
//遍历并输出文件
public class Tool1 {

	public static void main(String[] args) {
		System.out.println("please enter a path:");
		String path;
		Scanner sc = new Scanner(System.in);
		path = sc.next();
		File file = new File(path);
		Dir(file);

	}

	public static void Dir(File file) {

		File[] file1 = file.listFiles();
		for (File f : file1) {
			if (f.isDirectory()) {
				Dir(f);
			}
			System.out.println(f.getName());

		}
	}

}

• 遍历并输出文件及文件夹个数
  2.定义一个工具类，该类要求用户运行该程序时输入一个路径。该工具类会将该路径下的文件，文件夹的数量统计出来。

import java.io.File;
import java.util.Scanner;

import com.sun.org.apache.bcel.internal.generic.F2D;
//遍历并输出文件文件夹个数
public class Tool {
	private static int n = 0;
	private static int n1 = 0;

	public static void main(String[] args) {
		System.out.println("please enter a path:");
		String path;
		Scanner sc = new Scanner(System.in);
		path = sc.next();
		File file = new File(path);
		Dir(file);

		System.out.println(n-n1);
		System.out.println(n1);
	}

	public static void Dir(File file) {

		File[] file1 = file.listFiles();
		for (File f : file1) {
			if (f.isDirectory()) {
				n1++;
				Dir(f);
			}
			n++;

		}
	}
	
}

• 控制台以字符流保存文件及读取
  3.控制台输入的仿记事本小程序

import java.io.BufferedInputStream;
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PrintWriter;
import java.util.Scanner;

import org.junit.Test;

public class Tool2 {
	static String path ;
	
//控制台输入的仿记事本小程序
	public static void main(String[] args) {

	}

	@Test
	public void out() {
		Scanner sc = new Scanner(System.in);
		System.out.println("please enter the note path:");
		path = sc.next();
		BufferedReader br = null;
		PrintWriter pw = null;
		try {
			br = new BufferedReader(new InputStreamReader(System.in));
			pw = new PrintWriter(path);
			System.out.println("-------------------记事本----------------------");
			String str = null;

			while (!(str = br.readLine()).equals("exit")) {
				pw.write(str+"\n");
			}

		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		} finally {
			if (br != null) {
				try {
					br.close();
				} catch (IOException e2) {
					e2.printStackTrace();
				}
			}
			if (pw != null) {
				pw.close();
			}
		}

	}

	@Test
	public void in() {
		Scanner sc = new Scanner(System.in);
		System.out.println("please enter the note which you want to open:");
		path = sc.next();
		BufferedReader br = null;
		try {
			br = new BufferedReader(new InputStreamReader(new FileInputStream(path)));
			String str = null;
			while((str = br.readLine()) != null) {
				System.out.println(str);
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}