import java.io.File;
import java.io.FileFilter;

public class MyFileTree {

 public static void main(String[] args) {

  MyFileTree tree = new MyFileTree();
  tree.printFile(new File("c:/windows/system32"), 0);

 }

 
 public void printFile(File f, int indent) {

  if (f.isFile()) {
   for (int i = 0; i < indent; i++) {
    System.out.print("    ");
   }
   System.out.print(f.getName());
   System.out.println();
  } else if (f.isDirectory()) {
   for (int i = 0; i < indent; i++) {
    System.out.print("    ");
   }
   System.out.print("[" + f.getName() + "]");
   System.out.println();

   File[] listFiles = f.listFiles(new FileFilter() {
    public boolean accept(File f) {
     if (f.isDirectory())
      return true;
     if (f.getName().length() > 4
       && f.getName().substring(f.getName().length() - 4)
         .equalsIgnoreCase(".dll")) {
      return true;
     }
     return false;
    }
   });
   for (int i = 0; i < listFiles.length; i++) {
    printFile(listFiles[i], indent + 1);
   }

  } else {
   System.out.println("ERROR!");
  }

 }

}

------解决方案--------------------
File f = new File(path);
Files[] files = f.listFiles();
for(int i = 0, l = files.length; i < l; i++){
   File f1 = files[i];
}