content: package com.ctrip.framework.apollo.core.utils;
  
  import com.google.common.base.Strings;
  
  import org.slf4j.Logger;
  import org.slf4j.LoggerFactory;
  
  import java.net.URL;
  import java.net.URLDecoder;
  
  /**
   * @author Jason Song(song_s@ctrip.com)
   */
  public class ClassLoaderUtil {
    private static final Logger logger = LoggerFactory.getLogger(ClassLoaderUtil.class);
  
    private static ClassLoader loader = Thread.currentThread().getContextClassLoader();
    private static String classPath = "";
  
    static {
      if (loader == null) {
        logger.warn("Using system class loader");
        loader = ClassLoader.getSystemClassLoader();
      }
  
      try {
        URL url = loader.getResource("");
        // get class path
        if (url != null) {
          classPath = url.getPath();
          classPath = URLDecoder.decode(classPath, "utf-8");
        }
  
        // 如果是jar包内的，则返回当前路径
        if (Strings.isNullOrEmpty(classPath) || classPath.contains(".jar!")) {
          classPath = System.getProperty("user.dir");
        }
      } catch (Throwable ex) {
        classPath = System.getProperty("user.dir");
        logger.warn("Failed to locate class path, fallback to user.dir: {}", classPath, ex);
      }
    }
  
    public static ClassLoader getLoader() {
      return loader;
    }
  
  
    public static String getClassPath() {
      return classPath;
    }
  
    public static boolean isClassPresent(String className) {
      try {
        Class.forName(className);
        return true;
      } catch (ClassNotFoundException ex) {
        return false;
      }
    }
  }
  