How to load files on multiple platforms properly using Java?

Question

I have a java swing database application which needs to be run on Windows and Linux. My database connection details are stored in a XML file and I load them.

This application can load this properties on Linux properly but it is not working on Windows.

How do I load files on multiple platforms properly using Java?

This is the code:

PropertyHandler propertyWriter = new PropertyHandler();

List keys = new ArrayList();
keys.add("ip");
keys.add("database");
Map localProps = propertyWriter.read(keys, "conf" + File.separatorChar + "properties.xml", true);//if false load from the local properties

//get properties from the xml in the internal package
List seKeys = new ArrayList();
seKeys.add("driver");
seKeys.add("username");
seKeys.add("password");

Map seProps = propertyWriter.read(seKeys, "conf" + File.separatorChar + "properties.xml", true);

String dsn = "jdbc:mysql://" + (String) localProps.get("ip") + ":3306/" + (String) localProps.get("database");
jDBCConnectionPool = new JDBCConnectionPool((String) seProps.get("driver"), dsn, (String) seProps.get("username"), (String) seProps.get("password"));

File reader method:

public Map read(List properties, String path, boolean isConfFromClassPath)
{
    Properties prop = new Properties();
    Map props = new HashMap();
    try {

        if (isConfFromClassPath) {
            InputStream in = this.getClass().getClassLoader().getResourceAsStream(path);
            prop.loadFromXML(in);

            for (Iterator i = properties.iterator(); i.hasNext();) {
                String key = (String) i.next();
                props.put(key, prop.getProperty(key));
            }
            in.close();

        } else {
            FileInputStream in = new FileInputStream(path);
            prop.loadFromXML(in);

            for (Iterator i = properties.iterator(); i.hasNext();) {
                String key = (String) i.next();
                props.put(key, prop.getProperty(key));
            }
            in.close();
        }

    } catch (Exception ex) {
        ex.printStackTrace();
    }
    return props;
}

Usually you can go with the `/`, this works in most cases: `"conf/properties.xml"` (even on Windows). — Abdullah Jibaly, May 15 '12 at 04:55
@AbdullahJibaly It works in *all* cases. I never use backslash in filenames. — user207421, May 15 '12 at 23:51
Possible duplicate of [Platform independent paths in Java](https://stackoverflow.com/q/3548775/608639) — jww, Jul 29 '19 at 23:46

yiannis · Accepted Answer · 2012-05-15T05:16:01.217

5

If the file is in a jar file and accessed by the classpath then you should always use /.

The JavaDocs for the ClassLoader.getResource say that "The name of a resource is a '/'-separated path name that identifies the resource."

http://docs.oracle.com/javase/1.5.0/docs/api/java/lang/ClassLoader.html#getResource(java.lang.String)

edited May 15 '12 at 05:16

answered May 15 '12 at 05:06

yiannis

1,421
12
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score 1 · Answer 2 · answered May 15 '12 at 05:07

1

I'm not sure if there is the proper way, but one way is:

File confDir = new File("conf");
File propFile = new File(confDir, "properties.xml");

But in a scenario as simple as yours, I would just use /

answered May 15 '12 at 05:07

Cephalopod

14,632
7
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70

Not what I would have recommended, but still a nice and creative workaround. :) – Bananeweizen May 15 '12 at 05:15
1

I would not recommend this approach for this scenario as well, but there are others, for instance reading multiple files in a directory that was passed as an argument. – Cephalopod May 15 '12 at 10:58

score 0 · Answer 3 · answered May 15 '12 at 05:05

0

If it's a resource located in classpath, we can load it with following snippet:

getClass().getClassLoader().getResourceAsStream(
    "/META-INF/SqlQueryFile.sql")));

answered May 15 '12 at 05:05

James Gan

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score 0 · Answer 4 · answered Mar 13 '18 at 17:59

You can load all files on multiple platforms without any trouble.

Kindly use Matcher.quoteReplacement(File.separator) for replacing the slash.

It will works for every platform.

String fileLocation = "/src/service/files";

fileLocation  = fileLocation.replaceAll("/",Matcher.quoteReplacement(File.separator));

score -1 · Answer 5 · answered May 15 '12 at 04:58

-1

assuming that your file is in conf/properties.xml on Linux and conf\properties.xml on Windows, use File.pathSeparator instead of File.separator

answered May 15 '12 at 04:58

GreyBeardedGeek

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2
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Why? Path separators are used to to separate different paths (the colon in Unix or semi-colon in Windows). – Abdullah Jibaly May 15 '12 at 05:00
Noup, it is not working here I am getting an error when reading the file. – Harsha May 15 '12 at 05:02
1

That's incorrect. pathSeparator is ";" or ":". – James Gan May 15 '12 at 05:02
Yup, you're correct - got it backwards :-( – GreyBeardedGeek May 16 '12 at 11:22

How to load files on multiple platforms properly using Java?

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