Question

我试图返回方法的值但是循环抛出错误，因为返回必须在方法体中而不是在循环中。我正在使用system.out.println，它是有效的，但我想使用返回。

package AnimeAid;

import java.io.*;
import java.nio.charset.Charset;
import java.nio.file.Files;
import java.nio.file.Path;
import java.nio.file.Paths;

public class ReadFile {


    public void getFileInformation() throws IOException {   
        try{
            String file;
            file = "tra.srt";
            Charset charset = Charset.defaultCharset();
            Path path = Paths.get(file);
            BufferedReader reader = Files.newBufferedReader(path, charset);
            System.out.printf("Lines from %s:%n",file);
            String line;

            while((line = reader.readLine()) != null) {
                if (line.indexOf(':') != -1 && line.indexOf(',') != -1 && line.indexOf('0') != -1) { 
                    System.out.println(line.substring(0, 12)); 
                }
            }
        }catch(FileNotFoundException ex){
            System.err.println(ex);
        }

    }
}

Answer 1

你显然可以从for循环返回。

public String getFileInformation() throws IOException {   
 try{
    String file;
    file = "tra.srt";
    Charset charset = Charset.defaultCharset();
    Path path = Paths.get(file);
    BufferedReader reader = Files.newBufferedReader(path, charset);
    System.out.printf("Lines from %s:%n",file);
    String line;

    while((line = reader.readLine()) != null) {
    if (line.indexOf(':') != -1 && line.indexOf(',') != -1 && line.indexOf('0') != -1) { 
    return line.substring(0, 12); 
    }
    }
    }catch(FileNotFoundException ex){
    System.err.println(ex);
    }

    return "";
}

使用return inside循环和方法

1 个答案: