java缓冲区大小_java – BufferedReader中的缓冲区大小是多少？

构造函数中缓冲区大小的意义是什么？

BufferedReader(Reader in, int size)

正如我写的程序：

import java.io.*;

class bufferedReaderEx{

public static void main(String args[]){

InputStreamReader isr = null;

BufferedReader br = null;

try{

isr = new InputStreamReader(System.in);

// System.out.println("Write data: ");

// int i = isr.read();

// System.out.println("Data read is: " + i);

//Thus the InputStreamReader is useful for reading the character from the stream

System.out.println("Enter the data to be read by the bufferedReader: ");

//here isr is containing the lnefeed already so this is needed to be flushed.

br = new BufferedReader(isr, 2);

String str = br.readLine();

System.out.println("The data is : :" + str);

}catch(IOException e){

System.out.println("Can't read: " + e.getMessage());

}

}

}

输出：

Enter the data to be read by the bufferedReader: Hello world and hello world again

The data is: Hello world and hello world again

那么缓冲区大小意味着什么，因为我打算只读两个字符。但不是这样。