Java学习笔记——I/O流

朝辞白帝彩云间，千里江陵一日还。
两岸猿声啼不尽，轻舟已过万重山。

　　　　　　　　　　　　　　——早发白帝城

我们老师写代码有个特点，就是简洁。每一句的意图都十分明确。所以他讲课的速度也比较快。

跑题了，说说I/O流:

1、字节输入流

2、字符输入流

3、字节输出流

4、字符输出流

上代码：

public class FileInputStreamAndFileoutputSteamDemo {

    public static void main(String[] args) throws IOException {
        FileOutputStream fos = new FileOutputStream("/home/yanshaochen/public/abc.txt");
        byte[] bytes = new byte[1024];
        bytes = "金麟岂是池中物,一遇风云变化龙".getBytes();
        fos.write(bytes);
        fos.close();
        FileInputStream fis = new FileInputStream("/home/yanshaochen/public/abc.txt");
        String str = "";
        int data;
        while ((data = fis.read(bytes)) != -1) {
            str += new String(bytes, 0, data);
        }
        System.out.println(str);
        fis.close();
    }
}

public class WriterAndReader {

    public static void main(String[] args) throws IOException {
        String path = "/home/yanshaochen/public/abc.txt";
        Writer wt = new FileWriter(path);
        String str = "AAAAA";
        wt.write(str);
        wt.close();
        Reader rd = new FileReader(path);
        char[] chars = new char[16];
        int data;
        str = "";
        while ((data = rd.read(chars))!=-1) {
            str += new String(chars, 0, data);
        }
        System.out.println(str);
        rd.close();
    }
}

带缓冲区的字符输入输出流

public class BufferedReaderAndBufferedWriter {

    public static void main(String[] args) throws IOException {
        Writer fw = new FileWriter("/home/yanshaochen/public/abc.txt");
        BufferedWriter bw = new BufferedWriter(fw);
        String str = "AAAAAAAA";
        bw.write(str);
        bw.newLine();
        bw.close();
        Reader fr =new FileReader("/home/yanshaochen/public/abc.txt");
        BufferedReader br = new BufferedReader(fr);
        while ((str = br.readLine())!= null) {
            System.out.println(str);
        }
        br.close();
    }
}

字节流读写二进制

public class DataInputStreamDemo {

    public static void main(String[] args) throws IOException {
        //原始地址
        InputStream is = new FileInputStream("/home/yanshaochen/图片/2017-05-06 15-12-02屏幕截图.png");
        DataInputStream dis = new DataInputStream(is);
        //目标地址
        OutputStream os = new FileOutputStream("/home/yanshaochen/public/2017-05-06 15-12-02屏幕截图.png");
        DataOutputStream dos = new DataOutputStream(os);
        byte[] bytes = new byte[1024];
        int data;
        while((data = dis.read(bytes)) != -1){
            dos.write(bytes,0,data);
        }
        System.out.println("copy ok!");
        dos.close();
        dis.close();
    }
}