import java.io.File;

public class Test{
    //递归删除
    public static void deleteDir(File dir){
        if(dir.isDirectory()){
            File[] files = dir.listFiles();
            for(int i=0; i<files.length; i++) {
                deleteDir(files[i]);
            }
        }
        dir.delete();
    }
   
    public static void main(String args[]) {
        deleteDir(new File("c:\\temp\\2"));
    }
    
}

------解决方案--------------------
import java.io.*;
public class Exccmd {

  //Construct the application
  public Exccmd() {
  }
  //Main method
  public static void main(String[] args) {
  String cmd = "del /s"+你的目录;
  try {
    Runtime.getRuntime().exec(cmd);
  }
  catch (IOException ex) {
    ex.printStackTrace();
  }
  }
}