Java ClassLoader locateFile(String name)

Description

Return the location of the specified resource by searching the current directory, user home directory, the current classpath and the system classpath.

License

Apache License

Parameter

Parameter	Description
name	the name of the resource - usually a file name (absolute or relative)

Return

a URL of the resource location

Declaration

public static URL locateFile(String name) throws FileNotFoundException 

Method Source Code

//package com.java2s;
// Licensed under the Apache License, Version 2.0 (the "License");

import java.net.URL;
import java.io.File;
import java.io.IOException;
import java.io.FileNotFoundException;

public class Main {
    /*********************************************************************
     * Return the location of the specified resource by searching the
     * current directory, user home directory, the current classpath
     * and the system classpath. <p>
     */*from  ww w .  j  ava2 s  .c  o m*/
     * The code was inspired by Apache Commons class
     * <tt>ConfigurationUtils</tt> (authors Herve Quiroz, Oliver
     * Heger, and Emmanuel Bourg). <p>
     *
     * @param name the name of the resource - usually a file name
     * (absolute or relative)
     *
     * @return a URL of the resource location
     *
     * @throw FileNotFoundException if the resource cannot be found;
     * or if the 'name' is null or otherwise invalid
     ********************************************************************/
    public static URL locateFile(String name) throws FileNotFoundException {

        if (name == null)
            throw new FileNotFoundException("Null file name.");

        // attempt to create a URL directly
        try {
            return new URL(name);
        } catch (IOException e) {
            // let's make another attempt
        }

        // attempt to load from an absolute path, or from the current directory
        File file = new File(name);
        if (file.isAbsolute() || file.exists()) {
            try {
                return file.toURI().toURL();
            } catch (IOException e) {
                throw new FileNotFoundException("Malformed path: " + name);
            }
        }

        // attempt to load from the user home directory
        try {
            StringBuilder fName = new StringBuilder();
            fName.append(System.getProperty("user.home"));
            fName.append(File.separator);
            fName.append(name);
            file = new File(fName.toString());
            if (file.exists())
                return file.toURI().toURL();
        } catch (IOException e) {
            // let's make another attempt
        }

        // attempt to load from the context classpath
        ClassLoader loader = Thread.currentThread().getContextClassLoader();
        URL url = loader.getResource(name);
        if (url != null)
            return url;

        // attempt to load from the system classpath
        url = ClassLoader.getSystemResource(name);
        if (url != null)
            return url;

        throw new FileNotFoundException(name);
    }
}

Related

1. loadProperties(final String location)
2. loadProperties(String propFile)
3. loadPropertiesFromFile(File parent)
4. loadTextFile(final String location)
5. loadXml()
6. read(String fileName)
7. readFromFile(Object obj, String fileName)
8. readSampleJson(String name)
9. saveProperties(Properties properties, String name)