Java Reader reset()方法及实例

Java中阅读器类的reset()方法是用来重置流的。重置后，如果流已经被标记，那么该方法将尝试在标记处重新定位，否则它将尝试将其定位到起始位置。

语法。

public void reset()

参数。此方法不接受任何参数。

返回值。此方法不返回任何值。

异常。该方法会抛出IOException。

如果在输入输出时发生一些错误
如果流还没有被标记
如果标记已被废止
如果reset()方法不被支持。

下面的方法说明了reset()方法的工作。

程序1:

// Java program to demonstrate
// Reader reset() method
  
import java.io.*;
import java.util.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        try {
  
            String str = "GeeksForGeeks";
  
            // Create a Reader instance
            Reader reader
                = new StringReader(str);
  
            // Get the character
            // to be read from the stream
            int ch;
  
            // Read the first 10 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 < 10; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }
  
            System.out.println();
  
            // mark the stream for
            // 5 characters using reset()
            reader.mark(5);
  
            // reset the stream position
            reader.reset();
  
            // Read the 5 characters from marked position
            // to this reader using read() method
            for (int i = 0; i < 5; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出:

GeeksForGe
eks??

程序2。

// Java program to demonstrate
// Reader reset() method
  
import java.io.*;
import java.util.*;
  
class GFG {
    public static void main(String[] args)
    {
  
        try {
            String str = "GeeksForGeeks";
  
            // Create a Reader instance
            Reader reader
                = new StringReader(str);
  
            // Get the character
            // to be read from the stream
            int ch;
  
            // Read the first 10 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 < 10; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }
  
            System.out.println();
  
            // reset the stream position
            reader.reset();
  
            // Read the 5 characters from marked position
            // to this reader using read() method
            for (int i = 0; i < 5; i++) {
                ch = reader.read();
                System.out.print((char)ch);
            }
        }
        catch (Exception e) {
            System.out.println(e);
        }
    }
}

输出: