java如何生成可变表头的excel

import java.io.BufferedInputStream;import java.io.File;import java.io.FileInputStream;import java.io.IOException;import java.io.InputStream;import java.util.Properties;public class GetFilePlace {  public String getFilePath() {  String dir = System.getProperty("user.dir"); //获得tomcat所在的工作路径     //获取到存储了文件存储位置的filedir.properties 文件路径  String realDir = dir + File.separator + "src" + File.separator +"META-INF" + File.separator + "filedir.properties";      return realDir; }    public String GetValueByKey(String filePath, String key)   {   Properties pps = new Properties();   try {    InputStream in = new BufferedInputStream (new FileInputStream(filePath));     pps.load(in);    String value = pps.getProperty(key);    in.close();    return value;       }catch (IOException e) {    e.printStackTrace();    return null;   }  }   public String getFileDirFromProperties(String key) {  return GetValueByKey(getFilePath(),key); }  public static void main(String[] args) {  System.out.println(new GetFilePlace().getFileDirFromProperties("filePath")); }}