如何生成可变表头的excel详解编程语言

filePath=E/:/appData

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)); 
    } 
}