吴裕雄--天生自然 JAVA开发学习：流(Stream)、文件(File)和IO

BufferedReader br = new BufferedReader(new

                      InputStreamReader(System.in));

//使用 BufferedReader 在控制台读取字符

import java.io.*;

public class BRRead {

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

        char c;

        // 使用 System.in 创建 BufferedReader

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

        System.out.println("输入字符, 按下 'q' 键退出。");

        // 读取字符

        do {

            c = (char) br.read();

            System.out.println(c);

        } while (c != 'q');

    }

}

//使用 BufferedReader 在控制台读取字符

import java.io.*;

public class BRReadLines {

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

        // 使用 System.in 创建 BufferedReader

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

        String str;

        System.out.println("Enter lines of text.");

        System.out.println("Enter 'end' to quit.");

        do {

            str = br.readLine();

            System.out.println(str);

        } while (!str.equals("end"));

    }

}

import java.io.*;

//演示 System.out.write().

public class WriteDemo {

    public static void main(String args[]) {

        int b;

        b = 'A';

        System.out.write(b);

        System.out.write('\n');

    }

}

import java.io.*;

public class fileStreamTest {

    public static void main(String args[]) {

        try {

            byte bWrite[] = { 11, 21, 3, 40, 5 };

            OutputStream os = new FileOutputStream("test.txt");

            for (int x = 0; x < bWrite.length; x++) {

                os.write(bWrite[x]); // writes the bytes

            }

            os.close();

            InputStream is = new FileInputStream("test.txt");

            int size = is.available();

            for (int i = 0; i < size; i++) {

                System.out.print((char) is.read() + "  ");

            }

            is.close();

        } catch (IOException e) {

            System.out.print("Exception");

        }

    }

}

//文件名 :fileStreamTest2.java

import java.io.*;

public class fileStreamTest2 {

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

        File f = new File("a.txt");

        FileOutputStream fop = new FileOutputStream(f);

        // 构建FileOutputStream对象,文件不存在会自动新建

        OutputStreamWriter writer = new OutputStreamWriter(fop, "UTF-8");

        // 构建OutputStreamWriter对象,参数可以指定编码,默认为操作系统默认编码,windows上是gbk

        writer.append("中文输入");

        // 写入到缓冲区

        writer.append("\r\n");

        // 换行

        writer.append("English");

        // 刷新缓存冲,写入到文件,如果下面已经没有写入的内容了,直接close也会写入

        writer.close();

        // 关闭写入流,同时会把缓冲区内容写入文件,所以上面的注释掉

        fop.close();

        // 关闭输出流,释放系统资源

        FileInputStream fip = new FileInputStream(f);

        // 构建FileInputStream对象

        InputStreamReader reader = new InputStreamReader(fip, "UTF-8");

        // 构建InputStreamReader对象,编码与写入相同

        StringBuffer sb = new StringBuffer();

        while (reader.ready()) {

            sb.append((char) reader.read());

            // 转成char加到StringBuffer对象中

        }

        System.out.println(sb.toString());

        reader.close();

        // 关闭读取流

        fip.close();

        // 关闭输入流,释放系统资源

    }

}

import java.io.File;

public class CreateDir {

    public static void main(String args[]) {

        String dirname = "/tmp/user/java/bin";

        File d = new File(dirname);

        // 现在创建目录

        d.mkdirs();

    }

}

import java.io.File;

public class DirList {

    public static void main(String args[]) {

        String dirname = "/tmp";

        File f1 = new File(dirname);

        if (f1.isDirectory()) {

            System.out.println("目录 " + dirname);

            String s[] = f1.list();

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

                File f = new File(dirname + "/" + s[i]);

                if (f.isDirectory()) {

                    System.out.println(s[i] + " 是一个目录");

                } else {

                    System.out.println(s[i] + " 是一个文件");

                }

            }

        } else {

            System.out.println(dirname + " 不是一个目录");

        }

    }

}

import java.io.File;

public class DeleteFileDemo {

    public static void main(String args[]) {

        // 这里修改为自己的测试目录

        File folder = new File("/tmp/java/");

        deleteFolder(folder);

    }

    // 删除文件及目录

    public static void deleteFolder(File folder) {

        File[] files = folder.listFiles();

        if (files != null) {

            for (File f : files) {

                if (f.isDirectory()) {

                    deleteFolder(f);

                } else {

                    f.delete();

                }

            }

        }

        folder.delete();

    }

}