读取逗号分隔的配置文件的最佳方法是什么?

如果可以使用x=y而不是x、y,那么可以使用properties类。

如果你确实需要x,y,那么看看 java.util.Scanner 可以将分隔符设置为用作分隔符(JavaDoc显示了这样做的示例)。

import java.io.File;
import java.io.FileNotFoundException;
import java.util.Scanner;

class Main
{
    public static void main(final String[] argv)
    {
        final File file;

        file = new File(argv[0]);

        try
        {
            final Scanner scanner;

            scanner = new Scanner(file);

            while(scanner.hasNextLine())
            {
                if(scanner.hasNext(".*,"))
                {
                    String key;
                    final String value;

                    key = scanner.next(".*,").trim();

                    if(!(scanner.hasNext()))
                    {
                        // pick a better exception to throw
                        throw new Error("Missing value for key: " + key);
                    }

                    key   = key.substring(0, key.length() - 1);
                    value = scanner.next();

                    System.out.println("key = " + key + " value = " + value);
                }
            }
        }
        catch(final FileNotFoundException ex)
        {
            ex.printStackTrace();
        }
    }
}

和属性版本(对于解析来说更简单,因为没有)

import java.io.BufferedReader;
import java.io.FileReader;
import java.io.IOException;
import java.io.Reader;
import java.util.Properties;

class Main
{
    public static void main(final String[] argv)
    {
        Reader reader;

        reader = null;

        try
        {
            final Properties properties;

            reader = new BufferedReader(
                            new FileReader(argv[0]));
            properties = new Properties();
            properties.load(reader);
            System.out.println(properties);
        }
        catch(final IOException ex)
        {
            ex.printStackTrace();
        }
        finally
        {
            if(reader != null)
            {
                try
                {
                    reader.close();
                }
                catch(final IOException ex)
                {
                    ex.printStackTrace();
                }
            }
        }
    }
}

最好使用java.util.scanner类读取配置文件中的值,使用逗号作为分隔符。链接到JavaDoc:

http://java.sun.com/j2se/1.5.0/docs/api/java/util/Scanner.html

例如:

Scanner sc = new Scanner(new File("thing.config"));
sc.useDelimiter(",");
while (sc.hasNext()) {
   String token = sc.next();
}

我个人用的是一个叫斯蒂芬·奥斯特米勒的人的罐子,这是他的 Labeled CSV 语法分析器。这是一些示例代码。

LabeledCSVParser lcsvp = new LabeledCSVParser(
    new CSVParser(
        new StringReader(
            "Name,Phone\n" +
            "Stewart,212-555-3233\n" +
            "Cindy,212-555-8492\n"
        )
    )
);

while(lcsvp.getLine() != null){
    System.out.println(
        "Name: " + lcsvp.getValueByLabel("Name")
    );
    System.out.println(
        "Phone: " + lcsvp.getValueByLabel("Phone")
    );
}

try {
  BufferedReader cfgFile = new BufferedReader(new FileReader(new File("config.file")));
  String line = null;

  // Read the file line by line
  while ((line = cfgFile.readLine()) != null) {
    line.trim();
    // Ignore empty lines
    if (!rec.equals("")) {
       String [] fields = line.split(","); 
       String key = fields[0];
       String value = fields[1];  
       // TODO: Check for more than 2 fields
       // TODO: Add key, value pair to Hashmap  
    } // if
  } // while

  cfgFile.close();
} catch (IOException e) {
  System.out.println("Unexpected File IO Error");
}