Java中的PushbackReader类的read()方法用于从流中读取单个字符。此方法将流阻塞到:
- 它已从流中获取了一些输入。
- 发生了一些IOException
- 阅读时已到达流的末尾。
用法:
public int read()
参数:此方法不接受任何参数
返回值:此方法返回一个整数值,该整数值是从流中读取的整数值。范围从0到65535。如果未读取任何字符,则返回-1。
异常:如果输入输出时发生某些错误,则此方法将引发IOException。
下面的方法说明了read()方法的用法方式:
示例1:
// Java program to demonstrate
// PushbackReader read() method
import java.io.*;
import java.util.*;
class GFG {
public static void main(String[] args)
{
try {
// Initializing a StringReader
// and PushbackReader
String s = "GeeksForGeeks";
StringReader stringReader
= new StringReader(s);
PushbackReader pushbackReader
= new PushbackReader(stringReader);
// Get the character
// to be read from the stream
int ch;
// Read the first 5 characters
// to this reader using read() method
// This will put the str in the stream
// till it is read by the reader
for (int i = 0; i < 5; i++) {
ch = pushbackReader.read();
System.out.println("\nInteger value "
+ "of character read: "
+ ch);
System.out.println("Actual "
+ "character read: "
+ (char)ch);
}
// Close the stream using read()
pushbackReader.close();
System.out.println("Stream Closed.");
}
catch (Exception e) {
System.out.println(e);
}
}
}
输出:
Integer value of character read: 71 Actual character read: G Integer value of character read: 101 Actual character read: e Integer value of character read: 101 Actual character read: e Integer value of character read: 107 Actual character read: k Integer value of character read: 115 Actual character read: s Stream Closed.
示例2:
// Java program to demonstrate
// PushbackReader read() method
import java.io.*;
import java.util.*;
class GFG {
public static void main(String[] args)
{
try {
// Initializing a StringReader
// and PushbackReader
String s = "GFG";
StringReader stringReader
= new StringReader(s);
PushbackReader pushbackReader
= new PushbackReader(stringReader);
// Get the character
// to be read from the stream
int ch;
// Read the first 2 characters
// to this reader using read() method
// This will put the str in the stream
// till it is read by the reader
for (int i = 0; i < 2; i++) {
ch = pushbackReader.read();
System.out.println("\nInteger value "
+ "of character read: "
+ ch);
System.out.println("Actual "
+ "character read: "
+ (char)ch);
}
// Close the stream
pushbackReader.close();
System.out.println("Stream Closed.");
}
catch (Exception e) {
System.out.println(e);
}
}
}
输出:
Integer value of character read: 71 Actual character read: G Integer value of character read: 70 Actual character read: F Stream Closed.
参考: https://docs.oracle.com/javase/9/docs/api/java/io/PushbackReader.html#read–
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注:本文由纯净天空筛选整理自srinam大神的英文原创作品 PushbackReader read() method in Java with Examples。非经特殊声明,原始代码版权归原作者所有,本译文未经允许或授权,请勿转载或复制。