Java FilterReader reset()方法及示例
FilterReader类reset()方法
reset()方法在java.io包中可用。
reset()方法用于将流重置到mark()方法的最新调用所设置的位置。
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()方法在重置流时可能会引发异常。
IOException：如果给定参数无效，则可能引发此异常。
语法：
public void reset();
参数：
它不接受任何参数。
返回值：
该方法的返回类型为void，不返回任何内容。
示例
//Java程序演示示例
//reset()FilterReader的void方法的说明
import java.io.*;
public class ResetOfFR {
public static void main(String[] args) throws Exception {
Reader r_stm = null;
FilterReader fr_stm = null;
try {
//实例化StringReader和
//FilterReader-
r_stm = new StringReader("JavaWorld!!!!");
fr_stm = new FilterReader(r_stm) {};
//通过使用read()方法isto-
//从fr_stm读取字符
char ch1 = (char) fr_stm.read();
char ch2 = (char) fr_stm.read();
char ch3 = (char) fr_stm.read();
System.out.println("ch1: " + ch1);
System.out.println("ch2: " + ch2);
System.out.println("ch3: " + ch3);
//通过使用mark()方法isto-
//在此设置当前位置
//fr_stm-
System.out.println("fr_stm.mark(1): ");
fr_stm.mark(1);
char ch4 = (char) fr_stm.read();
char ch5 = (char) fr_stm.read();
System.out.println("ch4: " + ch4);
System.out.println("ch5: " + ch5);
//通过使用reset()方法isto-
//将流重置到位置
//通过调用mark()方法设置
System.out.println("fr_stm.reset(): ");
fr_stm.reset();
char ch6 = (char) fr_stm.read();
char ch7 = (char) fr_stm.read();
char ch8 = (char) fr_stm.read();
char ch9 = (char) fr_stm.read();
char ch10 = (char) fr_stm.read();
char ch11 = (char) fr_stm.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 {
//借助此块可以
//释放所有链接的必要资源
//与流
if (fr_stm != null) {
fr_stm.close();
}
}
}
}输出结果
ch1: J ch2: a ch3: v fr_stm.mark(1): ch4: a ch5: W fr_stm.reset(): ch4: a ch5: W ch6: o ch7: r ch8: l ch9: d