poi是Apache基金會的開放源碼函式庫,提供API給Java程式對Microsoft Office格式檔案讀和寫的功能。這里是對Excel的讀取下載/上傳實現;在一些需要導入導出數據時感覺比較有用;曾經在CRM中實現下載/上傳聯系人信息,不過當時不是自己負責的,總體來說下載比較容易實現,上傳由於格式必須與數據庫字段對應,顯得有些麻煩;這里為了demo方便,沒有與數據庫交互,使用的是Servlet實現;
依賴包:
1.commons-fileupload
2.commons-io
3.poi
下載地址http://poi.apache.org/ http://commons.apache.org/
下面是代碼實現
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.5"
xmlns="http://java.sun.com/xml/ns/javaee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/javaee
http://java.sun.com/xml/ns/javaee/web-app_2_5.xsd">
<servlet>
<servlet-name>PoiServlet</servlet-name>
<servlet-class>com.wf.web.PoiServlet</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>PoiServlet</servlet-name>
<url-pattern>/poitest.jspx</url-pattern>
</servlet-mapping>
<welcome-file-list>
<welcome-file>index.jsp</welcome-file>
</welcome-file-list>
</web-app>
顯示頁面
index.jsp
<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
<head>
<title>POI測試</title>
</head>
<body>
<a href="poitest.jspx?_m=poi_down">下載</a><br>
<form action="poitest.jspx?_m=poi_upload" method="post" enctype="multipart/form-data">
<input type="file" name="file">
<input type="submit" value="submit">
</form>
</body>
</html>
Servlet端Java代碼
PoiServlet.java
package com.wf.web;
import java.io.BufferedInputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import javax.servlet.ServletException;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.apache.commons.fileupload.FileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.servlet.ServletFileUpload;
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.poifs.filesystem.POIFSFileSystem;
public class PoiServlet extends HttpServlet {
private static final long serialVersionUID = 1L;
public void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
String method = request.getParameter("_m");
if("poi_down".equals(method)){
poi_down(request,response);
}else if("poi_upload".equals(method)){
poi_upload(request,response);
}
}
private void poi_upload(HttpServletRequest request,
HttpServletResponse response) {
if(ServletFileUpload.isMultipartContent(request)){
DiskFileItemFactory factory = new DiskFileItemFactory();
factory.setSizeThreshold(1024*512);
factory.setRepository(new File("D:/tempload"));
ServletFileUpload fileUpload=new ServletFileUpload(factory);
fileUpload.setFileSizeMax(10*1024*1024);//設置最大文件大小
try {
@SuppressWarnings("unchecked")
List<FileItem> items=fileUpload.parseRequest(request);//獲取所有表單
for(FileItem item:items){
//判斷當前的表單控件是否是一個普通控件
if(!item.isFormField()){
//是一個文件控件時
String excelFileName = new String(item.getName().getBytes(), "utf-8"); //獲取上傳文件的名稱
//上傳文件必須為excel類型,根據后綴判斷(xls)
String excelContentType = excelFileName.substring(excelFileName.lastIndexOf(".")); //獲取上傳文件的類型
System.out.println("上傳文件名:"+excelFileName);
System.out.println("文件大小:"+item.getSize());
System.out.println("\n---------------------------------------");
if(".xls".equals(excelContentType)){
POIFSFileSystem fileSystem = new POIFSFileSystem(item.getInputStream());
HSSFWorkbook workbook = new HSSFWorkbook(fileSystem);
HSSFSheet sheet = workbook.getSheetAt(0);
int rows = sheet.getPhysicalNumberOfRows();
for (int i = 0; i < rows; i++) {
HSSFRow row = sheet.getRow(i);
int columns = row.getPhysicalNumberOfCells();
for (int j = 0; j < columns; j++) {
HSSFCell cell = row.getCell(j);
String value = this.getCellStringValue(cell);
System.out.print(value + "|");
}
System.out.println("\n---------------------------------------");
}
System.out.println("success！");
}else{
System.out.println("必須為excel類型");
}
//順便把文件保存到硬盤,防止重名
// String newName=new SimpleDateFormat("yyyyMMDDHHmmssms").format(new Date());
// File file = new File("d:/upload");
// if(!file.exists()){
// file.mkdir();
// }
// item.write(new File("d:/upload/"+newName+excelContentType));
response.sendRedirect("index.jsp");
}
}
}catch (Exception e) {
e.printStackTrace();
}
}
}
private void poi_down(HttpServletRequest request,
HttpServletResponse response) {
response.setContentType("application/vnd.ms-excel;charset=UTF-8");
response.setHeader("Content-Disposition", "attachment;filename=data.xls");
ServletOutputStream stream = null;
try {
stream = response.getOutputStream();
} catch (IOException e1) {
e1.printStackTrace();
}
HSSFWorkbook workbook = new HSSFWorkbook();
HSSFCellStyle style = workbook.createCellStyle();
style.setAlignment(HSSFCellStyle.ALIGN_CENTER);//左右居中樣式
HSSFSheet sheet = workbook.createSheet("我的聯系人");
sheet.setColumnWidth(0, 2000);
sheet.setColumnWidth(1, 5000);
//創建表頭(第一行)
HSSFRow row = sheet.createRow(0);
//列
HSSFCell cell = row.createCell(0);
cell.setCellValue("姓名");
cell.setCellStyle(style);
HSSFCell cell2 = row.createCell(1);
cell2.setCellValue("電話");
cell2.setCellStyle(style);
//創建數據行
for(int i =1;i<=20;i++) {
HSSFRow newrow = sheet.createRow(i);
newrow.createCell(0).setCellValue("tom"+i);
newrow.createCell(1).setCellValue("135816****"+i);
}
try {
workbook.write(stream);
System.out.println("下載成功");
stream.flush();
stream.close();
} catch (Exception e) {
e.printStackTrace();
}
}
public void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
doGet(request, response);
}
//獲取單元格內不同類型值
public String getCellStringValue(HSSFCell cell) {
String cellValue = "";
switch (cell.getCellType()) {
case HSSFCell.CELL_TYPE_STRING:
cellValue = cell.getStringCellValue();
if(cellValue.trim().equals("")||cellValue.trim().length()<=0)
cellValue=" ";
break;
case HSSFCell.CELL_TYPE_NUMERIC:
cellValue = String.valueOf(cell.getNumericCellValue());
break;
case HSSFCell.CELL_TYPE_FORMULA:
cell.setCellType(HSSFCell.CELL_TYPE_NUMERIC);
cellValue = String.valueOf(cell.getNumericCellValue());
break;
case HSSFCell.CELL_TYPE_BLANK:
cellValue=" ";
break;
case HSSFCell.CELL_TYPE_BOOLEAN:
break;
case HSSFCell.CELL_TYPE_ERROR:
break;
default:
break;
}
return cellValue;
}
}
上傳后的Excel已經讀入內存,可以與數據庫交互,上傳字段與數據庫字段必須一致,否則會報錯;實際項目一般都是先下載Excel模板之后,用戶填寫模板上傳,模板中定義好數據格式;當然避免不了隨便把一個文件后綴改為xls了