JAVA获取文件绝对路径的方法

本文实例讲述了JAVA获取文件绝对路径的方法。分享给大家供大家参考。具体实现方法如下：

复制代码 代码如下:
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;
   }
  
   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;
}

希望本文所述对大家的Java程序设计有所帮助。