Java PushbackReader unread()方法

java.io.PushbackReader.unread(char[] cbuf) 方法推回一个字符将其复制到推回缓冲区前面的数组。此方法返回后，将下一个字符被读取 cbuf[0]，其后的字符cbuf[1]的值，依此类推。

1 语法

public void unread(char[] cbuf)

2 参数

cbuf：返回的字符数组。

3 返回值

无

4 示例 

package com.yiidian;

/**
 * 一点教程网： http://www.yiidian.com
 */
/**
 * java.io.PushbackReader.unread(char[] cbuf)方法的例子
 */
import java.io.*;

public class Demo {
    public static void main(String[] args) {
        String s = "Hello World";

        // create a new StringReader
        StringReader sr = new StringReader(s);

        // create a new PushBack reader based on our string reader
        PushbackReader pr = new PushbackReader(sr, 20);

        try {
            // read the first five chars
            for (int i = 0; i < 5; i++) {
                char c = (char) pr.read();
                System.out.print("" + c);
            }

            // change line
            System.out.println();

            // create a new array to unread
            char cbuf[] = {'w', 'o', 'r', 'l', 'd'};

            // unread into cbuf
            pr.unread(cbuf);

            // read five chars, which is what we unread from cbuf
            for (int i = 0; i < 5; i++) {
                char c = (char) pr.read();
                System.out.print("" + c);
            }

            // close the stream
            pr.close();

        } catch (IOException ex) {
            ex.printStackTrace();
        }
    }
}

输出结果为：

Hello
world