PushbackReader类提供了将将字符推回到流的字符流Reader。你可以通过PushbackReader(Reader in, int size)构造方法来构造推回PushbackReader对象，size表示回推字符数组大小。
实例：读取document目录下面的reader01.txt文件，然后将读取的字符数组转换成字符串，查看字符串中是否存在指定的字符串。如果存在指定的字符串，则将本次读取的字符数组推回到输入字符流中，然后再将其读取出来，进行输出（在输出前后追加<<和>>）。
package io.reader;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.PushbackReader;
public class PushbackReaderTest {
public static void main(String[] args) {
PushbackReader reader = null;
try {
// 构建PushbackReader字符流对象
reader = new PushbackReader(
new InputStreamReader(
new FileInputStream("document/reader01.txt")), 64);
char[] buffer = new char[64];
int len = 0;
while ( (len = reader.read(buffer)) != -1 ) {
String tempStr = new String(buffer, 0, len);
System.out.println( tempStr );
// 判断本次读取的字符串中是否存在“you”字符串
if ( tempStr.indexOf("you") != -1 ) {
// 将本次读取的字符数组推回到输入字符流
reader.unread(tempStr.toCharArray());
// 读取推回的字符流，然后输出
if ( (len = reader.read(buffer)) != -1 ) {
System.out.println("<<" + new String(buffer, 0, len) + ">>");
}
}
}
} catch (Exception e) {
e.printStackTrace();
} finally {
if ( null != reader ) {
try {
reader.close();
reader = null;
} catch (IOException e) {
e.printStackTrace();
}
}
}
}
}输出结果：
It’s not my way to love you just when no one’s looking. It’s no <<It’s not my way to love you just when no one’s looking. It’s no>> t my way to take your hand if I’m not sure. It’s not my way to <<t my way to take your hand if I’m not sure. It’s not my way to >> let you see what’s going on inside of me. When it’s a love you’ <<let you see what’s going on inside of me. When it’s a love you’>> ll not be needing you’re not free. Please stop pulling at my sl <<ll not be needing you’re not free. Please stop pulling at my sl>> eeve if you’re just playing. If you’ll not take the things you <<eeve if you’re just playing. If you’ll not take the things you >> make me want to give.
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