LineNumberReader类的reset()方法 (LineNumberReader Class reset() method)

• reset() method is available in java.io package.

  reset()方法在java.io包中可用。

• reset() method is used to reset this LineNumberReader stream to the position of the most recent mark was set by calling its mark() method.

  reset()方法用于将此LineNumberReader流重置为通过调用其mark()方法设置的最新标记的位置。

• reset() method is a non-static method, it is accessible with the class object only and if we try to access the method with the class name then we will get an error.

  reset()方法是一种非静态方法，只能通过类对象访问，如果尝试使用类名称访问该方法，则会收到错误消息。

• reset() method may throw an exception at the time of resetting the stream.

  reset()方法在重置流时可能会引发异常。

  IOException: This exception may throw when this stream has not been marked or set mark is invalid.

  IOException：如果尚未对此流进行标记或设置标记无效，则可能引发此异常。

Syntax:

句法：

    public void reset();

Parameter(s):

参数：

• It does not accept any parameter.

  它不接受任何参数。

Return value:

返回值：

The return type of the method is void, it returns nothing.

该方法的返回类型为void ，不返回任何内容。

Example:

例：

// Java program to demonstrate the example 
// of void reset() method of LineNumberReader
import java.io.*;
public class ResetOfLNR {
public static void main(String[] args) throws Exception {
FileReader fr_stm = null;
LineNumberReader line_r = null;
int val = 0;
try {
// Instantiates FileReader and LineNumberReader
fr_stm = new FileReader("D:\\includehelp.txt");
line_r = new LineNumberReader(fr_stm);
// By using read() method isto 
// read the character from line_r
char ch1 = (char) line_r.read();
char ch2 = (char) line_r.read();
char ch3 = (char) line_r.read();
System.out.println("ch1: " + ch1);
System.out.println("ch2: " + ch2);
System.out.println("ch3: " + ch3);
// By using mark() method isto
// set the current position in this
// line_r
System.out.println("line_r.mark(0): ");
line_r.mark(0);
char ch4 = (char) line_r.read();
char ch5 = (char) line_r.read();
System.out.println("ch4: " + ch4);
System.out.println("ch5: " + ch5);
// By using reset() method isto
// reset the stream to the position 
// set by the call mark() method
System.out.println("line_r.reset(): ");
line_r.reset();
char ch6 = (char) line_r.read();
char ch7 = (char) line_r.read();
char ch8 = (char) line_r.read();
char ch9 = (char) line_r.read();
char ch10 = (char) line_r.read();
char ch11 = (char) line_r.read();
System.out.println("ch4: " + ch6);
System.out.println("ch5: " + ch7);
System.out.println("ch6: " + ch8);
System.out.println("ch7: " + ch9);
System.out.println("ch8: " + ch10);
System.out.println("ch9: " + ch11);
} catch (Exception ex) {
System.out.println(ex.toString());
} finally {
// with the help of this block is to
// free all necessary resources linked
// with the stream
if (fr_stm != null) {
fr_stm.close();
if (line_r != null) {
line_r.close();
}
}
}
}
}

Output

输出量

ch1: J
ch2: A
ch3: V
line_r.mark(0):
ch4: A
ch5: W
line_r.reset():
ch4: A
ch5: W
ch6: O
ch7: R
ch8: L
ch9: D

翻译自: https://www.includehelp.com/java/linenumberreader-reset-method-with-example.aspx