Java IO基础总结

BufferedReader br = new BufferedReader(new 
                      InputStreamReader(System.in));

public int read(char[] cbuf,
                int off,
                int len)

InputStream f = new FileInputStream("C:/java/hello");

File f = new File("C:/java/hello");
InputStream out = new FileInputStream(f);

OutputStream f = new FileOutputStream("C:/java/hello")

File f = new File("C:/java/hello");
OutputStream f = new FileOutputStream(f);

package cn.csuftacm.poorguy.io.reader;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.File;
import java.io.FileFilter;
import java.io.FileReader;
import java.io.FileWriter;
import java.io.IOException;
import java.nio.channels.FileLock;

import javax.management.ListenerNotFoundException;
public class HomeWork {
	
	/**
	 * 测试最多可以创建多少个文件夹
	 * @param path
	 * @return
	 * 能嵌套创建多少个文件夹取决于文件的名字所占字符有关
	 * 文件的全名大小在不同的系统中有限制
	 */
	public static int maxFolderNumber(File path,String name) {
		int cnt = 0;
		while(path.mkdir()) {
			cnt++;
			path = new File(path.getPath()+"/"+name);
		}
		return cnt;
	}
	
	private static void TextMaxFolderNumber() {
		System.out.println("测试最大可嵌套文件夹个数：");
		File file1 = new File("Text1");//创建了255个文件夹 文件名new
		File file2 = new File("Text2");//创建了510个文件夹 文件名n
		File file3 = new File("Text3");//创建了510个文件夹 文件名1
		File file4 = new File("Text4"); //创建了146个文件夹 文件名newnew
		System.out.print("文件名new："+maxFolderNumber(file1,"new"));
		System.out.print("   文件名n："+maxFolderNumber(file2,"n"));
		System.out.print("   文件名1："+maxFolderNumber(file3,"1"));
		System.out.println("   文件名newnew："+maxFolderNumber(file4,"newnew"));
		
		//删除文件夹操作
		deleteFolder(file1);
		deleteFolder(file2);
		deleteFolder(file3);
		deleteFolder(file4);
	}
	
	public static class Filter implements FileFilter{
		@Override
		public boolean accept(File pathname){
			return pathname.getName().endsWith(".c")
					||pathname.getName().endsWith(".h")
					||pathname.isDirectory();
		}
	}
	
	/**
	 * 用来处理文件，挑选出代码的文件，进行计算
	 * @param file
	 */
	public static Fileinfo processfile(File file) {
		long codetemp = 0;
		long nodetemp = 0;
		long blanktemp = 0;
		Fileinfo info = new Fileinfo();
		if(file.isFile()&&(file.getName().endsWith(".h")
				||file.getName().endsWith(".c"))) {
			return caculateCode(file);
		}else if(file.isDirectory()){
			File []files = file.listFiles(new Filter());
			for (File f : files) {
				codetemp+=processfile(f).getCode();
				nodetemp+=processfile(f).getNode();
				blanktemp+=processfile(f).getBlank();
			}
		}
		info.setBlank(blanktemp);
		info.setCode(codetemp);
		info.setNode(nodetemp);
		return info;
	}
	
	/**
	 * 用来计算代码中代码行数，空行行数和注释行数
	 * @param file
	 */
	private static Fileinfo caculateCode(File file) {
		Fileinfo info = new Fileinfo();
		try (BufferedReader in = new BufferedReader(new FileReader(file))){
			String string;
			int cnt = 0;
			int blank = 0;
			int node = 0;
			while(null!=(string = in.readLine())){
				String temp = string.trim();
				//空行行数
				if(temp.length()==0) {
					blank++;
				//两种注释的行数
				}else if(temp.startsWith("/**")||temp.startsWith("*")
						||temp.startsWith("*/")||temp.startsWith("//")){
							node++;
				}
				cnt++;
			}
			info.setNode(node);
			info.setBlank(blank);
			info.setCode(cnt-node-blank);
		} catch (IOException e) {
			e.printStackTrace();
		}
		return info;
	}
	
	/**
	 * 统计文件的个数
	 * @param folder
	 * @return
	 */
	public static int fileNumber(File folder) {
		int cnt = 0;
		if(folder.isFile()) {
			return 1;
		}
		File []file = folder.listFiles();
		for (File f : file) {
			cnt+=fileNumber(f);
		}
		return cnt;
	}
	
	/**
	 * 统计文件夹的个数
	 * @param folder
	 * @return
	 */
	public static int folderNumber(File folder) {
		if(folder.isFile()) {
			return 0;
		}
		int cnt = 0;
		cnt++;
		File []files = folder.listFiles();
		for (File f : files) {
				cnt+=folderNumber(f);
		}
		return cnt;
	}
	
	/**
	 * 统计文件的大小（字节）
	 * 
	 * @param file 文件或文件夹
	 * @return
	 */
	public static long length(File file) {
		if (file.isFile())
			return file.length();
		// 文件夹
		long size = 0;
		// 遍历文件夹
		File[] files = file.listFiles();
		for (File f : files) {
				size += length(f);
		}
		return size;
	}
	
	/**
	 * 删除一个文件夹
	 * @param args
	 */
	public static void deleteFolder(File file) {
		if(file.isFile()) {
			file.delete();
		}else {
			File[] files = file.listFiles();
			for (File f : files) {
				deleteFolder(f);
			}
		}
		file.delete();
	}
	
	/**
	 * 一次性计算文件和文件夹的个数
	 * @param file
	 * @return
	 */
	public static Fileinfomation Fileinfo(File file) {
		Fileinfomation info = new Fileinfomation();
		long length = 0;
		long filecnt = 0;
		long foldercnt = 0;
		if(file.isFile()) {
			info.setFilecnt(1);
			info.setLength(file.length());
			return info;
		}
		foldercnt++;
		File []files = file.listFiles();
		for (File f : files) {
			Fileinfomation info1 = Fileinfo(f);
			length+=info1.getLength();
			filecnt+=info1.getFilecnt();
			foldercnt+=info1.getFoldercnt();
		}
		info.setLength(length);
		info.setFilecnt(filecnt);
		info.setFoldercnt(foldercnt);
		return info;
	}

	/**
	 * 文件复制操作
	 * copyfile
	 * @param args
	 */
	public static void copyfile(File file1,File file2) {
		if(!file2.exists()) {
			try {
				file2.createNewFile();
			} catch (IOException e) {
				// TODO Auto-generated catch block
				e.printStackTrace();
			}
		}
		String string;
		try (BufferedReader in = new BufferedReader(new FileReader(file1))){
			while(null!=(string=in.readLine())) {
				try (BufferedWriter out = new BufferedWriter(new FileWriter(file2,true))){
					out.write(string);
					out.write("\n");
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args) {
		//测试最大可以迭代的文件夹层次
		TextMaxFolderNumber();
		
		//计算linux文件夹内文件的数量，文件夹数量和文件夹大小
		File file1 = new File("/Users/poorguy/linux-4.19.8");
		TextLinuxCnt(file1);
		
		//代码分析，分析注释，空行和代码行的行数
		System.out.println("\nlinux-4.19.8  中 lib目录下，代码信息统计");
		File file2 = new File("/Users/poorguy/linux-4.19.8/lib");
		//CaculateProcess(file2);
		
		//测试文件复制操作
		File f1 = new File("Text/abc.txt");
		File f2 = new File("bcd.txt");
		//copyfile(f1, f2);
		//System.out.println("文件复制完毕");
		deleteFolder(new File("bcd"));
	}

	private static void CaculateProcess(File file) {
		Fileinfo info = processfile(file);
		System.out.println("代码行数："+info.getCode());
		System.out.println("注释行数："+info.getNode());
		System.out.println("空行行数："+info.getBlank());
	}

	private static void TextLinuxCnt(File file) {
		//分开计算部分
		long t1 = System.currentTimeMillis();
		System.out.print("文件个数："+fileNumber(file)+"\t");
		System.out.print("文件夹个数："+folderNumber(file)+"\t");
		System.out.print("文件大小："+length(file)+"\t");
		t1 = System.currentTimeMillis()-t1;
		System.out.println("运行时间："+t1);
		
		//合并计算
		long t2 = System.currentTimeMillis();
		Fileinfomation f = Fileinfo(file);
		System.out.print("文件个数："+f.getFilecnt()+"\t");
		System.out.print("文件夹个数："+f.getFoldercnt()+"\t");
		System.out.print("文件大小："+f.getLength()+"\t");
		t2 = System.currentTimeMillis()-t2;
		System.out.println("运行时间："+t2);
	}
}

package cn.csuftacm.poorguy.io.reader;

public class Fileinfomation {
	private long length = 0;
	private long filecnt = 0;
	private long foldercnt = 0;
	public long getLength() {
		return length;
	}
	public void setLength(long length) {
		this.length = length;
	}
	public long getFilecnt() {
		return filecnt;
	}
	public void setFilecnt(long filecnt) {
		this.filecnt = filecnt;
	}
	public long getFoldercnt() {
		return foldercnt;
	}
	public void setFoldercnt(long foldercnt) {
		this.foldercnt = foldercnt;
	}
}