Java BufferedReader mark()方法

java.io.BufferedReader.mark(int) 用于标记流中的当前位置。调用reset()将重新定位流。

1 语法

public void mark(int readAheadLimit)

2 参数

readAheadLimit：保留标记时要读取的字符数。

3 返回值

无

4 示例 

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * java.io.BufferedReader.mark(int)方法的例子
 */
import java.io.BufferedReader;
import java.io.FileInputStream;
import java.io.InputStream;
import java.io.InputStreamReader;

public class Demo {
    public static void main(String[] args) throws Exception {
        InputStream is = null;
        InputStreamReader isr = null;
        BufferedReader br = null;

        try {
            // open input stream test.txt for reading purpose.
            is = new FileInputStream("d:/test.txt");

            // create new input stream reader
            isr = new InputStreamReader(is);

            // create new buffered reader
            br = new BufferedReader(isr);

            // reads and prints BufferedReader
            System.out.println((char)br.read());
            System.out.println((char)br.read());

            // mark invoked at this position
            br.mark(26);
            System.out.println("mark() invoked");
            System.out.println((char)br.read());
            System.out.println((char)br.read());

            // reset() repositioned the stream to the mark
            br.reset();
            System.out.println("reset() invoked");
            System.out.println((char)br.read());
            System.out.println((char)br.read());

        } catch (Exception e) {
            // exception occurred.
            e.printStackTrace();
        } finally {
            // releases any system resources associated with the stream
            if(is!=null)
                is.close();
            if(isr!=null)
                isr.close();
            if(br!=null)
                br.close();
        }
    }
}

假设test.txt内容如下：

ABCDE

输出结果为：

A
B
mark() invoked
C
D
reset() invoked
C
D