迷失北京

package review;

import java.io.File;

public class TestFile {
	public static void main(String[] args) {
		File file = new File("D://test.txt");
		System.out.println(file);
		System.out.println(file.isFile());
	}
}

Result：
D:\test.txt
true

public class File
    implements Serializable, Comparable<File>
{

   ...
	private String path;
	...
/**
     * Creates a new <code>File</code> instance by converting the given
     * pathname string into an abstract pathname.  If the given string is
     * the empty string, then the result is the empty abstract pathname.
     *
     * @param   pathname  A pathname string
     * @throws  NullPointerException
     *          If the <code>pathname</code> argument is <code>null</code>
     */
    public File(String pathname) {
	if (pathname == null) {
	    throw new NullPointerException();
	}
	this.path = fs.normalize(pathname);
	this.prefixLength = fs.prefixLength(this.path);
    }
	
	
/**
     * Converts this abstract pathname into a pathname string.  The resulting
     * string uses the {@link #separator default name-separator character} to
     * separate the names in the name sequence.
     *
     * @return  The string form of this abstract pathname
     */
    public String getPath() {
	return path;
	    }
	
/**
     * Returns the pathname string of this abstract pathname.  This is just the
     * string returned by the <code>{@link #getPath}</code> method.
     *
     * @return  The string form of this abstract pathname
     */
    public String toString() {
	return getPath();
	    }

package org.wk.io;

import java.io.File;
import java.io.FilenameFilter;
import java.util.Arrays;
import java.util.regex.Pattern;

/**
 * 作用：初探File类，获取文件名称的小工具类，并检查某个文件名称是否在此文件集合中
 */

public class DirectoryList {
	public static void main(String[] args) {
		File path = new File(".");
		String list[] = null;
		if (args.length == 0) {
			list = path.list();
		} else
			list = path.list(new DirFilter(args[0]));
		Arrays.sort(list, String.CASE_INSENSITIVE_ORDER);
		
		for(String str : list) {
			System.out.println("File Name: " + str);
		}
	}
}

class DirFilter implements FilenameFilter {
	private Pattern pattern;

	public DirFilter(String regex) {
		this.pattern = Pattern.compile(regex);
	}

	@Override
	public boolean accept(File dir, String name) {
		return pattern.matcher(name).matches();
	}

}

BufferedInputStream b = new BufferedInputStream(new DataInputStream(new FileInputStream("xxx")));  

DataOutputStream d = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("...")));

BufferedInputStream b = new BufferedInputStream(new DataInputStream(new FileInputStream("xxx")));
BufferedReader reader = new BufferedReader(new FileReader("..."));
		
DataOutputStream d = new DataOutputStream(new BufferedOutputStream(new FileOutputStream("...")));
BufferedWriter writer = new BufferedWriter(new FileWriter("..."));

package typical.usage;

import java.io.BufferedReader;
import java.io.File;
import java.io.FileNotFoundException;
import java.io.FileReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.util.ArrayList;
import java.util.Arrays;

/**
 * @author Administrator 一个读写文件的小工具
 */
public class TextFile extends ArrayList<String> {
	private static final long serialVersionUID = 1L;

	// 读文件
	public static String read(String file) {
		StringBuilder builder = new StringBuilder();
		try {
			BufferedReader bf = new BufferedReader(new FileReader(
					new File(file).getAbsoluteFile()));

			try {
				String s = null;
				while ((s = bf.readLine()) != null) {
					builder = builder.append(s);
					builder.append("\n");
				}
			} catch (IOException e) {
				e.printStackTrace();
			} finally {
				try {
					bf.close();
				} catch (IOException e) {
					e.printStackTrace();
				}
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
		return builder.toString();
	}

	// 写文件
	public static void write(String file, String content) {
		try {
			PrintWriter pr = new PrintWriter(new File(file).getAbsoluteFile());

			try {
				pr.print(content);
			} finally {
				pr.close();
			}

		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}

	// 根据指定的正则表达式拆分文件
	public TextFile(String file, String regex) {
		super(Arrays.asList(read(file).split(regex)));
		if (get(0).equals(""))
			remove(0);
	}

	// 读文件
	public TextFile(String file) {
		this(file, "\n");
	}

	// 写文件
	public void write(String file) {
		try {
			PrintWriter pw = new PrintWriter(new File(file).getAbsoluteFile());

			try {
				for (String item : this) {
					pw.print(item);
				}
			} finally {
				pw.close();
			}
		} catch (FileNotFoundException e) {
			e.printStackTrace();
		}
	}
	
	public static void main(String[] args) {
		String file = read("D://IAReg.txt");
		System.out.println(file);
		
		write("D://b.txt", file);
		
		TextFile tf = new TextFile("D://b.txt");
		
		tf.write("D://c.txt");
		
		TextFile tf2 = new TextFile("D://b.txt", "\\W+");
		System.out.println(tf2);
	}
}

package typical.usage;

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
/**
 * 
 * @author wangkang
 * 打开一个文件用于字符输入，同时为了提高速度运用了缓冲。
 */
public class BufferedInputFile {
	public static String read(String fileName) throws IOException {
		BufferedReader bf = new BufferedReader(new FileReader(fileName));

		String s = null;
		StringBuilder bs = new StringBuilder();

		while ((s = bf.readLine()) != null) {
			bs = bs.append(s + "\n");
		}
		
		//关闭文件输入流
		bf.close();
		
		return bs.toString();
	}

	public static void main(String[] args) {
		try {
			System.out.println(read("D:\\IAReg.txt"));
		} catch (IOException e) {
			e.printStackTrace();
		}
	}
}

package typical.usage;

import java.io.ByteArrayInputStream;
import java.io.DataInputStream;
import java.io.IOException;

public class FormattedMemoryInputStream2 {
	public static void main(String[] args) throws IOException {
		DataInputStream in = new DataInputStream(new ByteArrayInputStream(
				BufferedInputFile.read("D:\\IAReg.txt").getBytes()));
		while (in.available() != 0) {
			System.out.println(in.readByte());

		}
	}
}

//基本的本件输出
package typical.usage;

import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.FileWriter;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringReader;

public class BasicFileOutput {
	public static void main(String[] args) throws IOException {
		String file = "D:\\test.out";
		BufferedReader in = new BufferedReader(new StringReader(
				BufferedInputFile.read("D:\\IAReg.txt")));
		PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(
				file)));
		int lineNum = 1;
		String s = null;
		while ((s = in.readLine()) != null) {
			lineNum++;
			System.out.println(lineNum + ":" + s);
			//将字符串的内容写进文件
			out.write(s);
		}
		in.close();
		out.close();
	}
}

//文件输出的快捷方式
package typical.usage;

import java.io.BufferedReader;
import java.io.IOException;
import java.io.PrintWriter;
import java.io.StringReader;

public class ShortCutFileOutput {
	public static void main(String[] args) throws IOException {
		String file = "D:\\test.out";
		BufferedReader in = new BufferedReader(new StringReader(
				BufferedInputFile.read("D:\\IAReg.txt")));
		PrintWriter out = new PrintWriter(file);
		int lineNum = 1;
		String s = null;
		while ((s = in.readLine()) != null) {
			lineNum++;
			// 将字符串的内容写进文件
			out.write(lineNum + ":" + s);
		}
		in.close();
		out.close();
		System.out.println(BufferedInputFile.read("D:\\test.out"));
	}
}

package typical.usage;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.DataInputStream;
import java.io.DataOutputStream;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;

public class StoringAndRecoveringData {
	public static void main(String[] args) throws IOException {
		DataOutputStream out = new DataOutputStream(new BufferedOutputStream(
				new FileOutputStream("D://a.java")));
		out.writeInt(12345);
		out.writeDouble(12345.000);
		out.writeUTF("上面的是一个整数和一个浮点数！！");
		out.writeChars("上面的是一个整数和一个浮点数！！");
		out.close();
		DataInputStream in = new DataInputStream(new BufferedInputStream(
				new FileInputStream("D://a.java")));

		System.out.println(in.readInt());
		System.out.println(in.readDouble());
		System.out.println(in.readUTF());
		System.out.println(in.readChar());
		in.close();
	}
}

package typical.usage;

import java.io.IOException;
import java.io.RandomAccessFile;

public class UsingRandomAccessingFile {
	static String file = "D://IAReg.txt";
	
	static void play() throws IOException {
		RandomAccessFile rf = new RandomAccessFile(file, "r");
		for(int i = 0; i < 11; i ++) {
			System.out.println(rf.readLine());
		}
		rf.close();
	}

	public static void main(String[] args) throws IOException {
		//读取数据
		play();
		RandomAccessFile rf = new RandomAccessFile(file, "rw");
		for(int i = 0; i < 3; i ++) {
			rf.writeUTF("哈哈哈");
		}
		rf.close();
		//测试修改结果
		play();
	}
}