import java.io.File;

import java.io.FilenameFilter;

import java.util.Arrays;

import java.util.regex.Pattern;

public class DirList {

    public static void main(String[] args) {

        File path = new File("./data/baiduvideo/");

        String[] list;

        if (args.length == 0)

            list = path.list();

        else {

            list = path.list(new DirFilter(args[0]));

        }

        Arrays.sort(list,String.CASE_INSENSITIVE_ORDER);//按字母排序

        for(String dirItem : list)

            System.out.println(dirItem);

    }

}

class DirFilter implements FilenameFilter {

    private Pattern pattern;

    public DirFilter(String regex){

        pattern = Pattern.compile(regex);

    }

    @Override

    public boolean accept(File dir, String name) {

        return pattern.matcher(name).matches();

    }

}

//这是list方法的内部实现,策略设计模式

/*public String[] list(FilenameFilter filter) {

    String names[] = list();

    if ((names == null) || (filter == null)) {

        return names;

    }

    ArrayList v = new ArrayList();

    for (int i = 0 ; i < names.length ; i++) {

        if (filter.accept(this, names[i])) {

        v.add(names[i]);

    }

}

    return (String[])(v.toArray(new String[v.size()]));

}*/

//匿名内部类改写，可读性不好

public class DirList {

    public static void main(final String[] args) {

        File path = new File("./data/baiduvideo/");

        String[] list;

        if (args.length == 0)

            list = path.list();

        else {

            list = path.list(new FilenameFilter() {

                private Pattern pattern = Pattern.compile(args[0]);

                @Override

                public boolean accept(File dir, String name) {

                    return pattern.matcher(name).matches();

                }

            });

        }

        Arrays.sort(list,String.CASE_INSENSITIVE_ORDER);//按字母排序

        for(String dirItem : list)

            System.out.println(dirItem);

    }

}

package testio;

import java.io.BufferedReader;

import java.io.BufferedWriter;

import java.io.ByteArrayInputStream;

import java.io.DataInputStream;

import java.io.FileReader;

import java.io.FileWriter;

import java.io.IOException;

import java.io.PrintWriter;

import java.io.StringReader;

public class BufferedInputFile {

    //1、缓冲输入文件

    public static String read(String filename) throws IOException{

        //BufferedReader目的是为了提高性能

        BufferedReader in = new BufferedReader(new FileReader(filename));

        String s;

        StringBuilder sb = new StringBuilder();

        while((s=in.readLine())!=null)

            sb.append(s);

            sb.append("\n");//readLine已经将换行符删了

        in.close();

        return sb.toString();

    }

    public static void main(String[] args) throws IOException {

        System.out.println(read("E:/eclipse/testnginx/src/testio/BufferedInputFile.java"));

    }

}

public class MemoryInput {

    //2、从内存输入

    public static void main(String[] args) throws IOException {

        StringReader in = new StringReader(

                BufferedInputFile

                        .read("E:/eclipse/testnginx/src/testio/MemoryInput.java"));

        int c;

        while ((c = in.read()) != -1)

            System.out.print((char) c);

    }

}

public class FormattedMemoryInput {

    //3、格式化内存输入--按字节读取字符，防止出现乱码

    public static void main(String[] args) throws IOException {

        DataInputStream in = new DataInputStream(new ByteArrayInputStream(

                BufferedInputFile.read(

                        "E:/eclipse/testnginx/src/testio/MemoryInput.java")

                        .getBytes()));

        while(true)

            System.out.print((char)in.readByte());

    }

}

public class BasicFileOutput {

    //1、基本文本输出，为了提供格式化机制，使用PrintWriter

    /*static String file = "BasicFileOutput.out";

    public static void main(String[] args) throws IOException {

        BufferedReader in = new BufferedReader(new FileReader(

                "E://eclipse//testnginx//src//testio//BasicFileOutput.java"));

        PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(

                file)));

        String s;

        int lineCount = 1;

        while ((s = in.readLine()) != null)

            out.println(lineCount++ + ":" + s);

        out.close();

        in.close();

    }*/

    //方式2从内存输入

    static String file = "BasicFileOutput.out";

    public static void main(String[] args) throws IOException {

        BufferedReader in = new BufferedReader(new StringReader(

                BufferedInputFile.read("E:/eclipse/testnginx/src/testio/BasicFileOutput.java")));

        PrintWriter out = new PrintWriter(new BufferedWriter(new FileWriter(

                file)));

        //PrintWriter out = new PrintWriter(file); //PrintWriter的一种快捷方式

        String s;

        int lineCount = 1;

        while ((s = in.readLine()) != null)

            out.println(lineCount++ + ":" + s);

        out.close();

        in.close();

    }

}