java IO流练习:文件复制、遍历子目录、复制所有子目录

import org.junit.Test;

import java.awt.*;
import java.io.*;
import java.net.URI;
import java.net.URISyntaxException;
import java.text.SimpleDateFormat;

/**
 * @author king
 *         Created by king on 2017/5/19.
 */
public class IOTrain {
    //    @Test
    public void testTime() {//测试函数运行时间
        long start = System.currentTimeMillis();
        for (int i = 0; i < 1; i++) {
            try {
                Thread.sleep(1000);
            } catch (InterruptedException e) {
                e.printStackTrace();
            }
        }
        long end = System.currentTimeMillis();
        SimpleDateFormat sdf = new SimpleDateFormat("s");
        System.out.println(sdf.format(end - start));
    }

    //    @Test
    public void createFile() {//创建a.txt
        File file = new File("D:\\file\\a.txt");
        try {
            file.createNewFile();
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //    @Test
    public void fileList() {//列出D盘下的所有文件、文件夹
        File file = new File("D:");
        String[] ss = file.list();
        for (String s : ss) System.out.println(s);
    }

    //    @Test
    public void fileList2() {//列出D盘下的所有文件、文件夹
        File file = new File("D:");
        File[] files = file.listFiles();
        for (File f : files) System.out.println(f.getPath());
    }

    //    @Test
    public void makeDir() {//创建文件夹
        File file = new File("D:\\file\\44");
        file.mkdir();
    }


    //    @Test
    public void testShowAllDir() {//显示D盘下所有的子文件
        String path = "D:";
        showAllDir(path);
    }

    public void showAllDir(String path) {
        File file = new File(path);
        File fs[] = file.listFiles();
        for (int i = 0; i < fs.length; i++) {
            if (fs[i].isDirectory()) {
                try {
                    showAllDir(fs[i].getAbsolutePath());
                } catch (Exception e) {
                }
            } else {
                System.out.println(fs[i].getAbsolutePath());
            }
        }
    }

    //    @Test
    public void browseBaidu1() {//用浏览器打开百度
        try {
            URI uri = new URI("http://www.baidu.com");
            Desktop.getDesktop().browse(uri);
        } catch (Exception e) {
        }
    }

    //    @Test
    public void browseBaidu2() {//用浏览器打开百度，完整版
        String webSite = "http://www.baidu.com";
        Desktop desktop = Desktop.getDesktop();
        if (Desktop.isDesktopSupported() && desktop.isSupported(Desktop.Action.BROWSE)) {
            URI uri = null;
            try {
                uri = new URI(webSite);
            } catch (URISyntaxException e) {
                e.printStackTrace();
            }
            try {
                desktop.browse(uri);
            } catch (IOException e) {
                e.printStackTrace();
            }
        }
    }

    //    @Test
    public void readByte() {// 从文件系统中的某个文件中获得输入字节
        try (FileInputStream fs = new FileInputStream("D:\\file\\1.txt")) {
            byte[] buffer = new byte[1024];
            int n = 0;
            while ((n = fs.read(buffer)) != -1) {
                System.out.println(new String(buffer));
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Test
    public void writeByte() {//FileOutputStream，意为文件输出流，是用于将数据写入File或 FileDescriptor的输出流。
        try (FileOutputStream fs = new FileOutputStream("D:\\file\\3.txt")) {
            fs.write("哈尔滨".getBytes());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }


    //    @Test
    public void copyByte() {//将1.txt拷贝到2.txt
        try (FileOutputStream w = new FileOutputStream("D:\\file\\2.txt");
             FileInputStream r = new FileInputStream("D:\\file\\1.txt")) {
            byte[] buffer = new byte[1024];
            int n = 0;
            while ((n = r.read(buffer)) != -1) {
                w.write(buffer, 0, n);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //    @Test
    public void readChar() {//FileReader类从InputStreamReader类继承而来。该类按字符读取流中数据。
        try (Reader reader = new FileReader("D:\\file\\1.txt")) {
            char[] buffer = new char[20];
            int n = 0;
            while ((n = reader.read(buffer)) != -1) {
                System.out.println(buffer);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //    @Test
    public void writeChar() {//FileWriter类从OutputStreamReader类继承而来。该类按字符向流中写入数据。
        try (Writer writer = new FileWriter("D:\\file\\1.txt")) {
            writer.write("哈尔滨");
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //    @Test
    public void copyChar() {//按字符流将1.txt复制给2.txt
        try (FileReader reader = new FileReader("D:\\file\\1.txt");
             FileWriter writer = new FileWriter("D:\\file\\2.txt")) {
            int n = 0;
            char[] buffer = new char[20];
            while ((n = reader.read(buffer)) != -1) {
                writer.write(buffer, 0, n);
            }
        } catch (IOException e) {
            e.printStackTrace();
        }
    }

    //    @Test
    public void FindFileByType() {//查找 *.bat
        File file = new File("D:");
        File[] find = file.listFiles(new FilenameFilter() {
            @Override
            public boolean accept(File dir, String name) {
                return name.endsWith(".bat");
            }
        });
        for (File f : find) System.out.println(f.getName());
    }

    //    @Test
    public void testCopyAllDir1() {
        String readPath = "D:\\file";//源地址
        String writePath = "D:\\file2";//目标地址
        new File(writePath).mkdirs();
        copyAllDir1(readPath, writePath);
    }

    public void copyAllDir1(String readPath, String writePath) {
        File file = new File(readPath);
        File[] fs = file.listFiles();
        for (int i = 0; i < fs.length; i++) {
            try {
                if (fs[i].isDirectory()) {
                    fs[i].mkdir();
                    copyAllDir1(fs[i].getAbsolutePath(), writePath + "\\" + fs[i].getName());
                } else {
                    System.out.println(fs[i].getAbsolutePath());
                }
            } catch (Exception e) {
            }
        }
    }

    //    @Test
    public void testCopyAllDir2() {
        String readPath = "D:\\file";//源地址
        String writePath = "D:\\file2";//目标地址
        new File(writePath).mkdir();
        copyAllDir2(readPath, writePath);
    }

    public void copyAllDir2(String readPath, String writePath) {//将readPath中的所有子文件拷贝到writePath目录下。
        //获取当前readPath目录下所有文件、文件夹，并存在fs[] 中
        File file = new File(readPath);
        File fs[] = file.listFiles();

        //fs!=null 排除空指针异常
        if (fs != null) {
            //遍历当前目录
            for (int i = 0; i < fs.length; i++) {
                //如果当前对象fs[i]是文件夹，则在目标地址中创建同名的文件夹。
                if (fs[i].isDirectory()) {
                    new File(writePath + "\\" + fs[i].getName()).mkdir();
                    copyAllDir2(fs[i].getPath(), writePath + "\\" + fs[i].getName());
                }

                //如果当前对象fs[i]是文件，那么按字节拷贝到目标地址。
                else {
                    try (FileInputStream readFile = new FileInputStream(fs[i].getPath());/*从这里读数据*/
                         FileOutputStream writeFile = new FileOutputStream(writePath + "\\" + fs[i].getName()))/*往这里写数据*/ {
                        byte[] buffer = new byte[1024];
                        int n = 0;
                        while ((n = readFile.read(buffer)) != -1) {
                            writeFile.write(buffer, 0, n);
                        }
                    } catch (IOException e) {
                        e.printStackTrace();
                    }
                }
            }
        }
    }


//    @Test
    public void mergeRandomAccessFile() {//将两个mp3文件合并。RandomAccessFile的唯一父类是Object
        try (RandomAccessFile r = new RandomAccessFile("c://1.mp3", "r");
             RandomAccessFile w = new RandomAccessFile("c://2.mp3", "rw")) {
            byte[] buffer = new byte[1024 * 1024];
            w.seek(1024 * 1024);//定位到末尾，MP3 avi
            int n = 0;
            while ((n = r.read(buffer)) != -1) {
                w.write(buffer, 0, n);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

//    @Test
    public void copyRandomAccessFile() {//复制文件。RandomAccessFile已经被JDK1.4的nio的"内存映射文件(memory-mapped files)"给取代了。
        try (RandomAccessFile r = new RandomAccessFile("c://1.wmv", "r");
             RandomAccessFile w = new RandomAccessFile("d://2.wmv", "rw")) {
            byte[] buffer = new byte[1024 * 1024];
            int n = 0;
            while ((n = r.read(buffer)) != -1) {
                w.write(buffer, 0, n);
            }
        } catch (Exception e) {
            e.printStackTrace();
        }
    }

//    @Test
    public void divideRandomAccessFile(){//将1.txt分割为多个
        try(RandomAccessFile r=new RandomAccessFile("D:\\file\\1.txt","r")){
            byte[] buffer=new byte[2];
            int n=0;
            int i=1;
            while((n=r.read(buffer))!=-1){
                RandomAccessFile w=new RandomAccessFile("D:\\file\\1_"+(i++)+".txt","rw");
                w.write(buffer,0,n);
            }
        }catch (IOException e) {
            e.printStackTrace();
        }
    }

    @Test
    public void mergeFile(){//将多个1_?.txt文件合并为一个1.txt文件
        File file=null;
        try(RandomAccessFile w=new RandomAccessFile("D:\\file\\1.txt","rw")){
            int i=1;
            while((file=new File("D:\\file\\1_"+(i++)+".txt")).exists()){
                RandomAccessFile r=new RandomAccessFile(file,"r");
                copyTo(r,w);
            }
        }catch(IOException e){e.printStackTrace();}
    }

    private void copyTo(RandomAccessFile r, RandomAccessFile w) throws IOException {
        byte[] buffer=new byte[8];
        int n=0;
        while((n=r.read(buffer))!=-1){
            w.write(buffer,0,n);
        }
    }
}