java - 我收到 "unreported exception ioexception; must be kept or declared to be thrown"

Question

这个问题已经有答案了:

Why am I getting "must be caught or declared to be thrown" on my program? (6 个回答)

已关闭 5 年前。

我收到错误“未报告的异常 ioException；必须保留或声明为抛出”。这是提供的路径或 try - catch block 中的错误。

import java.io.*;
import java.util.regex.*;

class RegexMobileExtractor {

    public static void main(String[] args) {
        try {
            Pattern p = Pattern.compile("(0|9)?[7-9][0-9]{9}");
            PrintWriter pw = new PrintWriter("C:\\Users\\HP\\Desktop\\CODE\\JAVA_EX\\copy\\output.txt");
            BufferedReader br = new BufferedReader(new FileReader("C:\\Users\\HP\\Desktop\\CODE\\JAVA_EX\\copy\\input.txt"));

            //PrintWriter pw = new PrintWriter("output.txt");
            //BufferedReader br = new BufferedReader(new FileReader("input.txt"));

            String line = br.readLine();
            while( line!= null) {
                Matcher m = p.matcher(line);
                while(m.find()) {
                    pw.println(m.group());
                }

                line = br.readLine();
            }

            pw.flush();
            pw.close();
            //br.close();
        } catch (FileNotFoundException obj) {
            System.out.println("errr occured");
        }
    }
}

Answer 1

这行代码:br.readLine();可能会抛出IOException。这是被破解的异常，编译器强制您处理它，这就是为什么您必须添加额外的catch block :

catch (IOException e) {
    e.printStackTrace();
}