[Java] java如何读取Excel简单模板

import java.io.file;
import java.io.fileinputstream;
import java.io.filenotfoundexception;
import java.io.ioexception;
import java.io.inputstream;
import java.io.pushbackinputstream;
import java.util.arraylist;
import java.util.hashmap;
import java.util.map;
import java.util.list;
import org.apache.poi.poixmldocument;
import org.apache.poi.openxml4j.exceptions.invalidformatexception;
import org.apache.poi.openxml4j.opc.opcpackage;
import org.apache.poi.poifs.filesystem.poifsfilesystem;
import org.apache.poi.ss.usermodel.cell;
import org.apache.poi.ss.usermodel.row;
import org.apache.poi.ss.usermodel.sheet;
import org.apache.poi.ss.usermodel.workbook;
import org.apache.poi.xssf.usermodel.xssfworkbook;
import org.apache.poi.hssf.usermodel.hssfcell;
import org.apache.poi.hssf.usermodel.hssfworkbook;
import org.apache.xmlbeans.impl.piccolo.io.fileformatexception;
/**
 *yanbiao 2016.10.25 
 */
public class excelutil {
 
  private static final string extension_xls = "xls";
  private static final string extension_xlsx = "xlsx";
 
/**
* 文件检查
*/
private void prereadcheck(string filepath) throws filenotfoundexception, fileformatexception {
 
file file = new file(filepath);
if (!file.exists()) {
throw new filenotfoundexception("导入的文件不存在：" + filepath);
}
if (!(filepath.endswith(extension_xls) || filepath.endswith(extension_xlsx))) {
throw new fileformatexception("传入的文件不是excel");
}
} 
 /**
   * 取得workbook对象
   * xls:hssfworkbook,03版
   * xlsx:xssfworkbook,07版
  */
 private workbook getworkbook(string filepath) throws ioexception, invalidformatexception { 
  //直接判断后缀来返回相应的workbook对象多数情况没问题，但是这个更保险，第3条已经说明  
  workbook wb = null;
  inputstream is = new fileinputstream(filepath);
  if (!is.marksupported()) {
    is = new pushbackinputstream(is, 8);
  }
  if (poifsfilesystem.haspoifsheader(is)) {
     return new hssfworkbook(is);
  }
  if (poixmldocument.hasooxmlheader(is)) {
    return new xssfworkbook(opcpackage.open(is));
  }
  throw new illegalargumentexception("您的excel版本目前不支持poi解析");
  }
 
  /**
   * 读取excel文件内容
   */
  public map<integer, list<string>> readexcel(string filepath) throws filenotfoundexception, fileformatexception {
  // 检查和获取workbook对象
  this.prereadcheck(filepath);
  workbook wb = null;
  map<integer,list<string>> map = new hashmap<integer, list<string>>();
  try {
    wb = this.getworkbook(filepath);
    // 默认只读取第一个sheet 
    sheet sheet = wb.getsheetat(0);
    int rowcount = sheet.getlastrownum();//逻辑行，包括空行
    int cellcount = sheet.getrow(0).getlastcellnum();//第一行（将来作为字段的行）有多少个单元格
    for (int i=0;i<rowcount;i++) {      //这里用最原始的for循环来保证每行都会被读取
     list<string> list = new arraylist<string>();
     row row = sheet.getrow(i);
     if(null!=row){
      for (int j=0;j<cellcount;j++) {
       list.add(getcellvalue(row.getcell(j)));  //这里也是用for循环，用cell c:row这样的遍历，空单元格就被抛弃了  
      }
      system.out.println("第"+(row.getrownum()+1)+"行数据："+list.tostring());
      map.put(row.getrownum(), list); 
      }else{
      for (int j=0;j<cellcount;j++) {
        list.add("无数据");   
      }
      system.out.println("第"+(i+1)+"行数据："+list.tostring());
      map.put(i, list);
    }   
    }  
  } catch (exception e) {
    system.out.println("读取excel异常："+e.getmessage());
    e.printstacktrace();
    } finally {
     if (wb != null) {
       try {
         wb.close();
      } catch (ioexception e) {
         e.printstacktrace();
       }
     }
     }
  return map;   
  }
  /**
   * 取单元格的值
   */
  private string getcellvalue(cell c) {
  if (c == null) {
    return "无数据";
  }
  string value = "";
  switch (c.getcelltype()){
  case hssfcell.cell_type_numeric://数字
     value = c.getnumericcellvalue()+"";
  break;
  case hssfcell.cell_type_string://字符串
    value = c.getstringcellvalue();
  break;
  case hssfcell.cell_type_boolean://boolean
    value = c.getbooleancellvalue()+"";
  break;
  case hssfcell.cell_type_formula://公式
    value = c.getcellformula()+"";
  break;
  case hssfcell.cell_type_blank://空值
    value= "无数据";
   break;
  case hssfcell.cell_type_error:
    value = "非法字符";
   break;
  default:
    value= "未知类型";
   break;  
  }
  return value;
  }
}