JAVA method to get the absolute path to a file
- 2020-04-01 03:40:09
- OfStack
This article illustrates a JAVA method for obtaining the absolute path to a file. Share with you for your reference. The specific implementation method is as follows:
/**
* Gets the value of a class class The absolute path to the file. This class could be JDK Its own class, also can be a user - defined class, or a third - party development package in the class.
* As long as the class can be loaded in this program, it can be located class The absolute path to the file.
*
* @param cls
* Of an object Class attribute
* @return This class of class The absolute path to the file location. Returns if there is no definition of the class null .
*/
private String getPathFromClass(Class cls) throws IOException {
String path = null;
if (cls == null) {
throw new NullPointerException();
}
URL url = getClassLocationURL(cls);
if (url != null) {
path = url.getPath();
if ("jar".equalsIgnoreCase(url.getProtocol())) {
try {
path = new URL(path).getPath();
}
catch (MalformedURLException e) {
}
int location = path.indexOf("!/");
if (location != -1) {
path = path.substring(0, location);
}
}
File file = new File(path.replaceAll("%20"," "));
path = file.getCanonicalPath();
}
return path;
}
/**
* For class class File location URL . This method is the most basic method of the class and can be called by other methods.
*/
private URL getClassLocationURL(final Class cls) {
if (cls == null) {
throw new IllegalArgumentException("class that input is null");
}
URL result = null;
final String clsAsResource = cls.getName().replace('.', '/').concat(".class");
final ProtectionDomain pd = cls.getProtectionDomain();
if (pd != null) {
final CodeSource cs = pd.getCodeSource();
if (cs != null) {
result = cs.getLocation();
}
if (result != null) {
if ("file".equals(result.getProtocol())) {
try {
if (result.toExternalForm().endsWith(".jar")|| result.toExternalForm().endsWith(".zip")) {
result = new URL("jar:".concat(result.toExternalForm()).concat("!/").concat(clsAsResource));
}
else if (new File(result.getFile()).isDirectory()) {
result = new URL(result, clsAsResource);
}
}
catch (MalformedURLException ignore) {
}
}
}
}
if (result == null) {
final ClassLoader clsLoader = cls.getClassLoader();
result = clsLoader != null ? clsLoader.getResource(clsAsResource): ClassLoader.getSystemResource(clsAsResource);
}
return result;
}I hope this article has been helpful to your Java programming.