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 { /**  * 读取文件，获取excel保存的根目录  * @return excel保存的根目录  */ 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";    /*String realDir = dir.substring(0, dir.length()-4) + File.separator +"webapps" + File.separator + "generateExcels"       + File.separator + "classes" + File.separator + "META-INF" + File.separator + "config" + File.separator + "filedir.properties"; */  return realDir; }  /**  * 获取filePath路径【properities文件】中key对应的值，  * @param filePath properities文件路径【包含properities文件】  * @param key 要查找的key值  * @return key对应的value  */  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;   }  }  /**  * 查询properities文件中可以对应的存储地点  * @param key 查询主键  * @return key对应的存储地址  */ public String getFileDirFromProperties(String key) {  return GetValueByKey(getFilePath(),key); }  public static void main(String[] args) {  System.out.println(new GetFilePlace().getFileDirFromProperties("filePath")); }}

import java.io.File;import java.text.SimpleDateFormat;import java.util.Calendar;public class GenerateFold{ /**  * 查询当前生成的excel需要存在在哪个路径，如果存在则存储在相应的位置，否则生成改目录， 每天生成一个文件夹，文件夹的命名规则为 年月日的时间戳  * @param foldName 生成excel保存路径  * @return   现在的excel需要保存路径  */ public String getFold(String foldName) {  SimpleDateFormat format = new SimpleDateFormat("yyyyMMdd");    String todayStr = format.format(Calendar.getInstance().getTime());    String foldPath = foldName + File.separator + todayStr;     File file = new File(foldPath);    if(!file.exists() && !file.isDirectory())  {   System.out.println("不存在");   file.mkdirs();  }  else  {   System.out.println("存在");  }  return foldPath; }}

import java.io.File;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.OutputStream;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Calendar;import java.util.List;import java.util.UUID;import org.apache.poi.hssf.usermodel.HSSFCell;import org.apache.poi.hssf.usermodel.HSSFCellStyle;import org.apache.poi.hssf.usermodel.HSSFRow;import org.apache.poi.hssf.usermodel.HSSFSheet;import org.apache.poi.hssf.usermodel.HSSFWorkbook;import org.apache.poi.hssf.util.Region;import org.apache.poi.ss.usermodel.CellStyle;import com.zcr.until.GetFilePlace;import com.zcr.until.User;/** * 生成excel * @author zcr * */public class GenerateExcel{ /**  * 通过关键字查询properties文件相应文件的存储位置，根据表头顺序将数据保存到相应文件路径的xls文件中, 文件的命名规则是时间戳加一串全球唯一编码  * @param fileDir       //查找文件存储根目录  * @param head       //表头  * @param list       //数据  * @return        //文件的保存路径及其名字的字符串  */ public <T> String generateExcels(String fileDir,String [] head,List<T> list)  {  //获得存储的路径  //String savePath = new GetFilePlace().getFileDirFromProperties(key);    //文件存储名字  String saveFileName = "";  SimpleDateFormat format = new SimpleDateFormat("yyyyMMddHHmmssSS");  saveFileName += format.format(Calendar.getInstance().getTime());    UUID uuid = UUID.randomUUID(); //全球唯一编码    saveFileName += "-" + uuid.toString();      HSSFWorkbook workbook = new HSSFWorkbook();  HSSFSheet sheet = workbook.createSheet();  workbook.setSheetName(0,"APP数据"); //设置表格工作簿名称  HSSFCellStyle cellStyle = workbook.createCellStyle();  cellStyle.setAlignment(CellStyle.ALIGN_CENTER);  cellStyle.setVerticalAlignment(CellStyle.VERTICAL_CENTER);    HSSFRow titleRow = sheet.createRow(0);  sheet.addMergedRegion(new Region(0,(short)0,0,(short)(head.length-1)));  HSSFCell titleCell = titleRow.createCell(0);  titleCell.setCellValue("AAP数据____ ");  titleCell.setCellStyle(cellStyle);  HSSFRow row1 = sheet.createRow(1);      //设置表头  for(int i = 0 ; i < head.length ; i++)  {   HSSFCell cell = row1.createCell(i);   cell.setCellValue(head[i]); //设置值   cell.setCellStyle(cellStyle);//设置样式  }      if(null != list && list.size() > 0)  {   int size = list.size();    Class classType = list.get(0).getClass();   for(int i = 0,rowNum=2 ; i < size ; i ++,rowNum++)   {    HSSFRow rows = sheet.createRow(rowNum);    T t = list.get(i);        //添加数据行    for(int j = 0 ; j < head.length ; j++)     {     //获得首字母     String firstLetter = head[j].substring(0,1).toUpperCase();           //获得get方法,getName,getAge等     String getMethodName = "get" + firstLetter + head[j].substring(1);          Method method;     try     {      //通过反射获得相应的get方法，用于获得相应的属性值      method = classType.getMethod(getMethodName, new Class[]{});            HSSFCell dataCell = rows.createCell(j);      try      {        System.out.print(getMethodName +":" + method.invoke(t, new Class[]{}) +",");        dataCell.setCellValue(method.invoke(t, new Class[]{}).toString());      }      catch (IllegalArgumentException e)      {       e.printStackTrace();      }      catch (IllegalAccessException e)      {       e.printStackTrace();      }      catch (InvocationTargetException e)      {       e.printStackTrace();      } //设置值      dataCell.setCellStyle(cellStyle);//设置样式     }     catch (SecurityException e)     {      e.printStackTrace();     }     catch (NoSuchMethodException e)     {      e.printStackTrace();     }         }    System.out.println();   }  }  else  {   System.out.println("没有数据");  }    //获得文件存储路径  //String fileDir = new GetFilePlace().getFileDirFromProperties(key);  saveFileName += ".xls";  String saveFilePathAndName = fileDir + File.separator + saveFileName;  OutputStream out = null;  try  {   out = new FileOutputStream(saveFilePathAndName);   try   {    workbook.write(out);//保存文件   }   catch (IOException e)   {    // TODO Auto-generated catch block    e.printStackTrace();   }  }  catch (FileNotFoundException e)  {   // TODO Auto-generated catch block   e.printStackTrace();  }  finally  {   try   {    out.close();   }   catch (IOException e)   {    // TODO Auto-generated catch block    e.printStackTrace();   }  }    return saveFilePathAndName; }  /**  * 提供外界调用的接口，生成以head为表头，list为数据的excel  * @param head //数据表头  * @param list //数据  * @return  //excel所在的路径  */ public <T> String generateExcel(String [] head,List<T> list) {  final String FilePath = "filePath";  String saveFilePathAndName = "";   //获得存储的根目录  String savePath = new GetFilePlace().getFileDirFromProperties(FilePath);    //获得当天存储的路径  String realSavePath = new GenerateFold().getFold(savePath);    //生成excel并将存储的路径返回（包含文件名）  saveFilePathAndName = generateExcels(realSavePath, head, list);    return saveFilePathAndName; }   public static void main(String[] args) {  String [] head = {"name","sex","adress","height","age","jj"};    List<User> list = new ArrayList<User>();  User user1 = new User("zhangsan",1,1.1f,"北京","男","AA");  User user2 = new User("lisi",22222,3.2f,"上海","女","BB");    list.add(user1);  list.add(user2);    System.out.println(new GenerateExcel().generateExcel(head,list));  //System.out.println(new GenerateExcel().generateExcels("E://appData//20151104",head,list)); }}