JavaIO框架

流的概念

• 概念：内存与存储设备之间传输数据的通道

流的分类

按照流向划分

• 输入流（读）：将存储设备中的内容读到内存中因为read需要循环，所以不能直接read = fileInputStream.read()

public class InputStream {
    public static void main(String[] args) throws IOException {
        FileInputStream fileInputStream = new FileInputStream("d:\\\\test.txt");
        int read = 0;
        while ((read=fileInputStream.read())!=-1){
            System.out.print((char)read);
        }
        fileInputStream.close();
    }
}

• 输出流（写）：将内存中的内容写入到存储设备中

public class OutPutStream {
    public static void main(String[] args) throws Exception {
        FileOutputStream fileOutputStream = new FileOutputStream("d:\\\\text.txt",true);
//        fileOutputStream.write(97);
//        fileOutputStream.write('c');
        String str = "是最帅的";
        fileOutputStream.write(str.getBytes(StandardCharsets.UTF_8));
        fileOutputStream.close();
        System.out.println("执行结束");
    }
}

• 复制文件：使用输入输出流实现

public class CopyDemo {
    public static void main(String[] args) throws Exception {
        FileInputStream fileInputStream = new FileInputStream("C:\\\\Users\\\\youya\\\\Desktop\\\\b1f7d58510723aa4326f2009991068a6.jpg");
        FileOutputStream fileOutputStream = new FileOutputStream("C:\\\\Users\\\\youya\\\\Desktop\\\\handsomeboy.jpg");
        byte[] b = new byte[1024];
        int count = 0;
        while ((count = fileInputStream.read(b))!=-1){
            fileOutputStream.write(b,0,count);
        }
        fileInputStream.close();
        fileOutputStream.close();
        System.out.println("执行结束");
    }
}

按照单位划分

• 字节流：以字节为单位，可以读写所有数据
• 字符流：以字符为单位，只能读写文本数据

按照功能划分

• 节点流：具有实际传输数据的读写功能

FileInputStream

• 过滤流：在节点流的基础上增强功能

BufferInputStream

字节流