java-io

摘要：包几乎包含了所有操作输入输出需要的类。所有这些流类代表了输入源和输出目标。输入流表示从一个源读取数据，输出流表示向一个目标写数据。但本节讲述最基本的和流与相关的功能。读取控制台输入的控制台输入由完成。有多种构造方法可用来创建对象。

package com.learn;

import org.omg.CORBA.PUBLIC_MEMBER;

import java.io.*;


/**
 * Created by fiz on 7/10/17.
 * 

 * Java.io 包几乎包含了所有操作输入、输出需要的类。所有这些流类代表了输入源和输出目标。
 * Java.io 包中的流支持很多种格式，比如：基本类型、对象、本地化字符集等等。
 * 一个流可以理解为一个数据的序列。输入流表示从一个源读取数据，输出流表示向一个目标写数据。
 * Java 为 I/O 提供了强大的而灵活的支持，使其更广泛地应用到文件传输和网络编程中。
 * 但本节讲述最基本的和流与 I/O 相关的功能。我们将通过一个个例子来学习这些功能。
 * 

 * 

 * 

 * 读取控制台输入:
 * 

 * Java 的控制台输入由 System.in 完成。
 * 为了获得一个绑定到控制台的字符流，你可以把 System.in 包装在一个 BufferedReader 对象中来创建一个字符流。
 * 下面是创建 BufferedReader 的基本语法：
 */


public class FileStreamTest {


    public static void readDir(String dir) {
        /**
         *   读取指定目录下的文件夹，并只返回文件，
         */
        File file = new File(dir);
        if (file.isDirectory()) {
            System.out.println("这个是个文件夹");
        } else {
            System.out.println();
        }

    }

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

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

        System.out.println("请输入你的要输入的内容");
        String input = bufferedReader.readLine();
        System.out.println(input);


        /**
         * FileInputStream
         *该流用于从文件读取数据，它的对象可以用关键字 new 来创建。
         *有多种构造方法可用来创建对象。
         *可以使用字符串类型的文件名来创建一个输入流对象来读取文件
         */
        InputStream inputStream = new FileInputStream("/Users/fiz/Documents/JavaProject/JavaProject.iml");
        byte[] buffer = new byte[1000];
        while (inputStream.read(buffer) > 0) {
            System.out.println(inputStream.read(buffer));
        }


        /**
         *  输出文件
         */


        File f = new File("/Users/fiz/Documents/JavaProject/demo.txt");
        FileOutputStream fop = new FileOutputStream(f);
        // 构建FileOutputStream对象,文件不存在会自动新建
        OutputStreamWriter outputStreamWriter = new OutputStreamWriter(fop);
        outputStreamWriter.write("demo");
        outputStreamWriter.close();


        /**
         * PipedOutputStream/PipedInputStream
         * 不能用于同一个线程中，主要是要去不同线程获取
         */

        final PipedOutputStream pipedOutputStream = new PipedOutputStream();
        final PipedInputStream pipedInputStream = new PipedInputStream(pipedOutputStream);


        Thread thread1 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    pipedOutputStream.write("Hello world, pipe!".getBytes());
                } catch (IOException e) {
                }
            }
        });

        Thread thread2 = new Thread(new Runnable() {
            @Override
            public void run() {
                try {
                    int data = pipedInputStream.read();
                    while (data != -1) {
                        System.out.print((char) data);
                        data = pipedInputStream.read();
                    }

                } catch (IOException e) {

                }
            }
        });
        thread1.start();
        thread2.start();


        /**
         * InputStream
         */
        InputStream inputStream1 = new FileInputStream("/Users/fiz/Documents/JavaProject/JavaProject.iml");
        byte[] bytesRead = new byte[1024];
        int data = inputStream1.read(bytesRead);
        while (data != -1) {
            //do something with data...
            System.out.println((char) data);
            data = inputStream1.read();
        }
        inputStream1.close();


        /**
         * FileOutputStream
         */
        File file = new File("demo.txt");
        FileOutputStream fileOutputStream = new FileOutputStream(file);
        int num = 10;
        while (num > 0) {
            fileOutputStream.write("deno+
".getBytes());
            num = num - 1;
        }
        fileOutputStream.close();


        /**
         *FileInputStream 读取文件
         */


        FileInputStream fileInputStream = new FileInputStream(file);
        int read = fileInputStream.read();
        while (read != -1) {

            System.out.println((char) fileInputStream.read());
            read = fileInputStream.read();
        }


        /**
         * inputStreamReader
         */


        InputStream inputStream2 = new FileInputStream("demo.txt");
        Reader inputStreamReader = new InputStreamReader(inputStream2);

        int data2 = inputStreamReader.read();
        while (data2 != -1) {
            char theChar = (char) data2;
            System.out.println("inputStreamReader");
            System.out.println(theChar);
            data2 = inputStreamReader.read();
        }


        /**
         *
         */
        OutputStream outputStream = new FileOutputStream("demo.txt");
        Writer outputStreamWriter1 = new OutputStreamWriter(outputStream);

        outputStreamWriter1.write("Hello World");

        outputStreamWriter1.close();


        /**
         * FileWriter
         */

        FileWriter fileWriter = new FileWriter(file);
        fileWriter.write("This
 is
 an
 example
");
        fileWriter.flush();// 刷掉缓冲区的内容
        fileWriter.close();


        /**
         * FileReader
         */
        FileReader fileReader = new FileReader(file);
        int fileReader_data = fileReader.read();
        while (fileReader_data != -1) {
            fileReader_data = fileReader.read();
            System.out.println((char) fileReader_data);
        }


        /**
         *BufferedReader
         */

        BufferedReader bufferedReader1 = new BufferedReader(new FileReader(file));
        String line = bufferedReader1.readLine();
        System.out.println("BufferedReader" + line);
        bufferedReader1.close();

        // 循环读取
//        while (line != null) {
//            // process line
//        }


        /**
         *BufferedWriter
         */
        BufferedWriter bufferedWriter = new BufferedWriter(new FileWriter("demo.txt", true));
        bufferedWriter.write("this is a demo process");
        int count = 10;
        while (count > 0) {
            bufferedWriter.write("this is a demo process
");
            count = count - 1;
        }
        bufferedWriter.close();

        File file1 = new File("test.txt");
        FileWriter fw = new FileWriter(file1);
        BufferedWriter bw = new BufferedWriter(fw);
        bw.write("demo");
        System.out.println("File written Successfully");


        /**
         *FilterWriter  虚拟类
         */


        /**
         *
         */
        LineNumberReader lineNumberReader = new LineNumberReader(new FileReader(file1));
        String line1 = lineNumberReader.readLine();
        while (line != null) {


            line = lineNumberReader.readLine();
            System.out.println(line + lineNumberReader.getLineNumber());
        }

    }


}

做个记录