Kann kein Objekt (AudioFile in diesem Beispiel) für ein leeren String erzeugen

[mueller91]

hallo,
ich wollte fragen, warum er, wenn er ein Leerzeichen als String übergeben kriegt, immer die Fehlermeldung schreibt:
Kann kein AudioFile erzeugen für:
Ich hab schon so ziemlich alles rumprobiert, aber nichts geht.

Das wäre mein Code:

public class AudioFile {
	private String pathname = "", filename = "", interpret = "",  titel = "" , autor = "", song = "";
	
	public AudioFile(String s){
		parsePathname(s);
		parseFilename(getFilename());
	}
	
	public AudioFile(){}

	public void parsePathname(String s){

		
		if (s.equals("")) {
            pathname = "";
            filename = "";
        }

        if (s.trim().equals("")) {
            pathname = s;
            filename = s;
        } 
        
		if(s.trim().equals("-") || s.trim().equals("")){
			filename = s;
			pathname = s;
		}
		
		if(s.trim() != "" && !s.trim().equals("-")){
			if(s.contains(":") && java.io.File.separatorChar == '/'){
				s = s.replaceAll(":", "");
				pathname = java.io.File.separatorChar + s;
			}
			if(s.contains("\\")){
				s = s.replace('\\', '/');
			}
			s = s.replaceAll("/+", "/");
			s = s.replace('/', java.io.File.separatorChar);
			pathname = s;
			filename = s.substring(s.lastIndexOf(java.io.File.separatorChar)+ 1, s.length());	
		}	
		
		if(((!s.contains("\\") || !s.contains("/")) && !s.contains("-") && s.trim() == "")){
			pathname = "";
			filename = "";
		}
	}
	
	public String getPathname(){return pathname;}
	public String getFilename(){return filename;}
	
	public void parseFilename(String filename){
		
		if(filename.equals(" - ") || filename.equals(".mp3")){
			interpret = "";
			titel = "";
		}
		if((!filename.contains(" - ") || !filename.equals("-") || !(filename.equals("")))){
			interpret = "";
			titel = filename.substring(0, filename.lastIndexOf("."));
		}
		if(filename.equals("-")){
			interpret = "";
			titel = "-";
		}
		
		if(filename.trim().equals("-")){
			interpret = "";
			titel = "";
		}
		
		if (filename.contains(" - ") && filename.contains(".") && !(filename.trim().equals(""))){
			autor = filename.substring(0, filename.lastIndexOf(" - "));
			interpret = autor.trim();
			song = filename.substring(filename.lastIndexOf(" - ")+ 2, filename.lastIndexOf("."));
			titel = song.trim();
		}
		if (filename.length() > 4 && filename.contains(".") && !filename.contains(" - ")){
			interpret = "";
			titel = filename.substring(0, filename.lastIndexOf("."));
		}	
	
	}
	
	public String getAuthor(){return interpret;}
	public String getTitle(){return titel;}

	public String toString(){
		if (getAuthor().trim() == "" && getTitle().trim() == ""){
			return "";
		}
		if (getAuthor() == "") {
			return titel;
		}
		else {
			return getAuthor() + " - " + getTitle();
		}
	}
}

Ich sag schon mal dankeschön im voraus 🙂

 

[Ralph-Uwe]

Hallo,

ist doch klar, Du versuchst einen leerten String zu zerlegen...
aber wo nichts ist, kann man nicht zerlegen.

Wie rufst Du deine Klasse auf?

 

[mueller91]

über ne testklasse.
des ist die testklasse:

import junit.framework.TestCase; 

public class AudioFileTest extends TestCase {

    private static char sep;

    private static String root = "/";

    private static String pathNames[];

    private static String expectedPathNames[];

    private static String expectedFileNames[];

    private static String authors[];

    private static String titles[];

    private static String toStrings[];

    public void setUp() {
        try {
            EmulateOtherOs.reset(); // no emulation
            // EmulateOtherOs.emulateWindows();
            // EmulateOtherOs.emulateLinux();
            // EmulateOtherOs.emulateMac();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
        sep = java.io.File.separatorChar;
        String osname = System.getProperty("os.name");
        if (osname.toLowerCase().indexOf("win") >= 0)
            root = "C:" + sep;

        pathNames = new String[] {
                root + "home" + sep + "meier" + sep + "Musik" + sep
                        + "Falco - Rock Me Amadeus.mp3",
                root + "home" + sep + "db-admin" + sep
                        + "Frankie Goes To Hollywood - The Power Of Love.ogg",
                root + "tmp" + sep + "Deep Purple - Smoke On The Water.wav",
                root + "my-tmp" + sep + "file.mp3",
                "Falco - Rock Me Amadeus.mp3",
                "file.mp3",
                ".." + sep + "music" + sep + "audiofile.au",
                "   A.U.T.O.R   -   T.I.T.E.L   .EXTENSION",
                "Hans-Georg Sonstwas - Blue-eyed boy-friend.mp3",
                // some more ugly test cases
                "", " ", "//your-tmp/part1//file.mp3/",
                "../your-tmp/..//part1//file.mp3/", "\\file.mp3",
                "\\part1\\\\file.mp3\\", "\\part1\\/file.mp3",
                "/MP3-Archiv/.nox", "/MP3-Archiv/Falco - Rock me Amadeus.",
                "-", " -  " };

        expectedPathNames = new String[] {
                root + "home" + sep + "meier" + sep + "Musik" + sep
                        + "Falco - Rock Me Amadeus.mp3",
                root + "home" + sep + "db-admin" + sep
                        + "Frankie Goes To Hollywood - The Power Of Love.ogg",
                root + "tmp" + sep + "Deep Purple - Smoke On The Water.wav",
                root + "my-tmp" + sep + "file.mp3",
                "Falco - Rock Me Amadeus.mp3",
                "file.mp3",
                ".." + sep + "music" + sep + "audiofile.au",
                "   A.U.T.O.R   -   T.I.T.E.L   .EXTENSION",
                "Hans-Georg Sonstwas - Blue-eyed boy-friend.mp3",
                // some more ugly test cases
                "",
                " ",
                sep + "your-tmp" + sep + "part1" + sep + "file.mp3" + sep,
                ".." + sep + "your-tmp" + sep + ".." + sep + "part1" + sep
                        + "file.mp3" + sep, sep + "file.mp3",
                sep + "part1" + sep + "file.mp3" + sep,
                sep + "part1" + sep + "file.mp3",
                sep + "MP3-Archiv" + sep + ".nox",
                sep + "MP3-Archiv" + sep + "Falco - Rock me Amadeus.", "-",
                " -  " };

        expectedFileNames = new String[] { "Falco - Rock Me Amadeus.mp3",
                "Frankie Goes To Hollywood - The Power Of Love.ogg",
                "Deep Purple - Smoke On The Water.wav", "file.mp3",
                "Falco - Rock Me Amadeus.mp3", "file.mp3", "audiofile.au",
                "   A.U.T.O.R   -   T.I.T.E.L   .EXTENSION",
                "Hans-Georg Sonstwas - Blue-eyed boy-friend.mp3",
                // some more ugly test cases
                "", " ", "", "", "file.mp3", "", "file.mp3", ".nox",
                "Falco - Rock me Amadeus.", "-", " -  " };

        authors = new String[] { "Falco", "Frankie Goes To Hollywood",
                "Deep Purple", "", "Falco", "", "", "A.U.T.O.R",
                "Hans-Georg Sonstwas",
                // some more ugly test cases
                "", "", "", "", "", "", "", "", "Falco", "", "" };

        titles = new String[] { "Rock Me Amadeus", "The Power Of Love",
                "Smoke On The Water", "file", "Rock Me Amadeus", "file",
                "audiofile", "T.I.T.E.L", "Blue-eyed boy-friend",
                // some more ugly test cases
                "", "", "", "", "file", "", "file", "", "Rock me Amadeus", "-",
                "" };

        toStrings = new String[] { "Falco - Rock Me Amadeus",
                "Frankie Goes To Hollywood - The Power Of Love",
                "Deep Purple - Smoke On The Water", "file",
                "Falco - Rock Me Amadeus", "file", "audiofile",
                "A.U.T.O.R - T.I.T.E.L",
                "Hans-Georg Sonstwas - Blue-eyed boy-friend",
                // some more ugly test cases
                "", "", "", "", "file", "", "file", "",
                "Falco - Rock me Amadeus", "-", "" };
    }

    public void tearDown() {
        try {
            EmulateOtherOs.reset();
        } catch (Exception e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        }
    }

    public void testSettersAndGetters() {
        // Use the constructor without arguments
        String current = null;
        try {
            for (int i = 0; i < pathNames.length; i++) {
                String p = pathNames[i];
                current = p;

                AudioFile af = new AudioFile();
                af.parsePathname(p);
                af.parseFilename(af.getFilename());

                assertEquals("getPathname() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", expectedPathNames[i],
                        af.getPathname());
                assertEquals("getFilename() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", expectedFileNames[i],
                        af.getFilename());
                assertEquals("getAuthor() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", authors[i], af.getAuthor());
                assertEquals("getTitle() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", titles[i], af.getTitle());
                assertEquals("toString() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", toStrings[i], af.toString());
            }
        } catch (Exception e) {
            fail("Kann kein AudioFile erzeugen fuer: " + current);
        }
    }

    public void testCtor() {
        // Perform the same getter and setter tests by using the ctor with one
        // argument for construction
        String current = null;
        try {
            for (int i = 0; i < pathNames.length; i++) {
                String p = pathNames[i];
                current = p;

                AudioFile af = new AudioFile(p);
                assertEquals("getPathname() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", expectedPathNames[i],
                        af.getPathname());
                assertEquals("getFilename() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", expectedFileNames[i],
                        af.getFilename());
                assertEquals("getAuthor() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", authors[i], af.getAuthor());
                assertEquals("getTitle() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", titles[i], af.getTitle());
                assertEquals("toString() fuer Testfall [" + i + "]: " + p
                        + " nicht korrekt", toStrings[i], af.toString());
            }
        } catch (Exception e) {
            fail("Kann kein AudioFile erzeugen fuer: " + current);
        }
    }

    // A test case for the treatment of drive letters
    public void test_TreatmentOfDriveLetters_01() {
        AudioFile af = new AudioFile();
        af.parsePathname("Z:\\part1\\\\file.mp3\\");

        char sepchar = java.io.File.separatorChar;

        if (isWindows()) {
            // On Windows we expect "Z:\part1\file.mp3\"
            assertEquals("Pathname stored incorrectly", "Z:" + sepchar
                    + "part1" + sepchar + "file.mp3" + sepchar,
                    af.getPathname());
        } else {
            // On Unix we expect "/Z/part1/file.mp3/"
            assertEquals("Pathname stored incorrectly", sepchar + "Z" + sepchar
                    + "part1" + sepchar + "file.mp3" + sepchar,
                    af.getPathname());
        }
        assertEquals("Returned filename is incorrect", "", af.getFilename());
    }

    // A test case for the treatment of drive letters
    public void test_TreatmentOfDriveLetters_02() {
        AudioFile af = new AudioFile();
        af.parsePathname("Z:part1\\\\file.mp3\\");

        char sepchar = java.io.File.separatorChar;

        if (isWindows()) {
            // On Windows we expect "Z:part1\file.mp3\"
            assertEquals("Pathname stored incorrectly", "Z:" + "part1"
                    + sepchar + "file.mp3" + sepchar, af.getPathname());
        } else {
            // On Unix we expect "/Z/part1/file.mp3/"
            assertEquals("Pathname stored incorrectly", sepchar + "Z" + sepchar
                    + "part1" + sepchar + "file.mp3" + sepchar,
                    af.getPathname());
        }
        assertEquals("Returned filename is incorrect", "", af.getFilename());
    }

    /*--------------------------------------------------------------------------
     * Auxiliary methods 
     */

    private boolean isWindows() {
        return System.getProperty("os.name").toLowerCase().indexOf("win") >= 0;
    }
}

der Test SetterAndGetters ruft die Methode parsePathname auf

 

[Murray]

Hier

        } catch (Exception e) {
            fail("Kann kein AudioFile erzeugen fuer: " + current);
        }

ist im Exception-Objekt noch die exakte Information enthalten, a) was nicht klappt und b) an welcher Stelle im Code das passiert. Lass dir doch mal die Exception mit

e.printStackTrace();

ausgeben.