有谁知道如何解析这样的文本文件？

Question

I am developing Android app using JAVA.

I have a text file like this which is on the internet

http://www2.compute.com.tw/~yflin/music.txt

and it shows like this

Name="testMusic1" Uri="http://www2.compute.com.tw/test1.mp3" Author="chali" Length=125 Icon="xxx" Lang="台语"
Name="testMusic2" Uri="http://www2.compute.com.tw/test2.mp3" Author="yflin" Length=123 Icon="xxx" Lang="国语"
Name="testMusic3" Uri="http://www2.compute.com.tw/test3.mp3" Author="kkj" Length=132 Icon="xxx" Lang="英文"

but as far as I know, I know how to parse .csv file and I also know how to parse xml file, using XPath expressing,

but! is there any easier way to parse text file like this/?? is there any good API I can use to parse text file like this??? or using the JAVA Scanner and useDelimiter ???

is there any examples written in JAVA?? 'cause I really cannot look up any more... Have been already search/survey for a long long time. Can someone help me??

Answer 1

Here is a complete tested working program. Just put this file where your music.txt is and run it. Also it uses the Scanner class.

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

public class Program {

    public static void main(String[] args) throws Exception{
        FileReader file = new FileReader("music.txt");
        Scanner scanner = new Scanner(file);
        while(scanner.hasNextLine()){
            String line = scanner.nextLine().trim();
            String[] tokens = line.split("\\s+");
            for(int i = 0; i < tokens.length; i++){
                String[] elements = tokens[i].split("=");
                System.out.println(elements[0] + ": " + elements[1]);
            }
            System.out.println();
        }
        scanner.close();
    }
}

Sample Output

Name: "testMusic1"
Uri: "http://www2.compute.com.tw/test1.mp3"
Author: "chali"
Length: 125
Icon: "xxx"
Lang: "test1"

Name: "testMusic2"
Uri: "http://www2.compute.com.tw/test2.mp3"
Author: "yflin"
Length: 123
Icon: "xxx"
Lang: "test2"

Name: "testMusic3"
Uri: "http://www2.compute.com.tw/test3.mp3"
Author: "kkj"
Length: 132
Icon: "xxx"
Lang: "test3"

VVV

Answer 2

One possibility is String.split().

EXAMPLE:

public class Split {

  static final String s = 
    "Name=\"testMusic1\"   Uri=\"http://www2.compute.com.tw/test1.mp3\"   Author=\"chali\"";

  public static void main (String[] args) {
    String[] nameValuePairs = s.split("\\s+"); // Split each item in string on whitespace (\s+)
    for (int i=0; i < nameValuePairs.length; i++) {
      String[] nv = nameValuePairs[i].split("=");  // Split the resulting name/value pair on "="
      System.out.println ("pair[" + i + "]: (" + nameValuePairs[i] + "), name=" + nv[0] + ", value=" + nv[1] + ".");
    }
  }

}

SAMPLE OUTPUT:

pair[0]: (Name="testMusic1"), name="Name, value="testMusic1".
pair[1]: (Uri="http://www2.compute.com.tw/test1.mp3"), name=Uri, value="http://www2.compute.com.tw/test1.mp3".
pair[2]: (Author="chali"), name=Author, value="chali".

Answer 3

The problem here is that you have not provided a proper syntax for your input, and designing a parser based examples is ... dodgy.

For example, if we assume that all examples will look like that, then String.split("\\\\s+") followed by String.split("=") will do the job. Or you could do the same thing using Scanner .

But if other examples (that you haven't seen yet) were a bit different, this may not work. For instance:

• the key/value pairs might be in a different order,
• the key names might have different casing,
• the key names might contain spaces,
• the values might contain spaces,
• there might be some escaping convention in the quoted strings to deal with embedded quote characters, etcetera,
• there might be no space between the end-quote of a value and the next key name,

On short, it is doubtful that there is sufficient information in those examples for you (or anyone) to implement an parser that will work for all inputs.