缓冲处理流

1、缓冲处理流：BufferedReader、BufferedWriter、BufferedInputStream、BufferedOutputStream

2、通过构造器，传入节点流

（1）BufferedReader 本类组合

private Reader in;

（2）BufferedWriter 本类组合

private Writer out;

（3）BufferedInputStream 继承父类 FilterInputStream

protected volatile InputStream in;

（4）BufferedOutputStream 继承父类 FilterOutputStream

protected OutputStream out;

3、内部组合缓冲区数组，构造器可以指定缓冲区大小，默认大小 8192

（1）BufferedReader

private char cb[];

（2）BufferedWriter

private char cb[];

（3）BufferedInputStream

protected volatile byte buf[];

（4）BufferedOutputStream

protected byte buf[];

4、输入流的抽象父类：OutputStream、Writer，都定义 flush 方法，所有的输入流都没有 flush 方法

5、Writer 的子类 / 组合缓冲数组的流，需要 flush 才能输出写入

6、调用 close / 缓冲区数组写满时，会自动调用 flush

7、关闭 BufferedReader、BufferedWriter、BufferedInputStream、BufferedOutputStream，只需要关闭外层流即可，底层自动关闭节点流

 

（例）拷贝文本

try (BufferedReader br = new BufferedReader(new FileReader("C://fileRead.txt"));
     BufferedWriter bw = new BufferedWriter(new FileWriter("D://fileWrite.txt"))) {
    String line;
    while ((line = br.readLine()) != null) {//边读边写
        bw.write(line);
        bw.newLine();//写一行分隔符，行分隔符字符串由系统属性line.separator定义，并不一定是单个换行符 \n
    }
} catch (IOException e) {
    e.printStackTrace();
}

 

（例）拷贝文件

try (BufferedInputStream bis = new BufferedInputStream(new FileInputStream("C://fileRead.txt"));
     BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream("D://fileWrite.txt"))) {
    byte[] bytes = new byte[1024];
    int length;
    while ((length = bis.read(bytes)) != -1) {//边读边写
        bos.write(bytes, 0, length);//不调用write(byte b[])，防止写入多余数据
    }
} catch (IOException e) {
    e.printStackTrace();
}