Java后台代码实现POI文件的导入导出
前言
工作中常常会用到POI的导入导出功能,今天为大家详细介绍一下平时用到的最多的导入Excel表格数据和导出数据为Excel表格的相关代码操作!本案例是SpringBoot项目,废话不多说上代码!
1.Controller层代码
//相关导包
import java.io.File;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.ResponseBody;
import org.springframework.web.multipart.MultipartFile;
import com.baidu.entity.Student;
import com.baidu.mapper.StudentMapper;
import com.baidu.utils.ExcelUtils;
import com.baidu.utils.FileUtils;
@Controller
public class StudentController {
@Autowired
private StudentMapper studentMapper;
//导出数据到Excel表格内
@RequestMapping("/exportExcel")
public void exportExcel(HttpServletResponse response,Student stu){
//查询要导出数据集合
List<Student> list = studentMapper.getExcelList();
String [] columnNames= {"编号","姓名","性别","生日"};
String [] columns= {"sid","sname","sex","birthday"};
ExcelUtils.exportExcel(response, list, columnNames, columns, "工作簿", "汇总");
}
//将Excel表格信息导入到数据库
@RequestMapping("/uploadFile")
@ResponseBody
public boolean uploadFile(HttpServletRequest request,Student stu,MultipartFile myfile,HttpServletResponse response) {
try {
//调用工具类FileUtils上传,前台传来的文件形参为myfile
String newFileName = FileUtils.upload(myfile, request);
String realPath = request.getSession().getServletContext().getRealPath("file");
//将Excel文件的内容放入到String类型的双层数组中
String[][] strings = ExcelUtils.readexcell(realPath+File.separator+newFileName, 1);
//循环数组,依次拿取数组内的数据放入到实体类的对象里,以便于添加数据到数据库的表单内
for (int i = 0; i < strings.length; i++) {
String [] stuData=strings[i];
Student user=new Student();
//从索引为1的开始拿数据,因为Excel表格内第一行是主键id,添加数据不需要id,不过如果在这写了也无所谓,没影响,添加的sql注意就好了.
user.setSname(stuData[1]);
user.setSex(stuData[2]);
user.setBirthday(stuData[3]);
studentMapper.addStu(user);
}
return true;
} catch (Exception e) {
// TODO: handle exception
return false;
}
}
}
2.用到的几个工具类
总共用到了三个工具类,工具类里面的方法可能不是都有用,不过我记不清楚用的哪几个了,就全部复制过来了,有兴趣可以仔细研究下,不过工具类,粘贴拿过去用就好了,多几个方法也问题不大.
第一个:ExcelUtils
//工具类所在包名
package com.XXX.utils;
//导包
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.UnsupportedEncodingException;
import java.lang.reflect.Method;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.List;
import javax.servlet.http.HttpServletResponse;
import org.apache.poi.hssf.usermodel.HSSFCell;
import org.apache.poi.hssf.usermodel.HSSFCellStyle;
import org.apache.poi.hssf.usermodel.HSSFDateUtil;
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;
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.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
/**
* poi操作excel
* @author Administrator
*/
public class ExcelUtils {
/**
* ***************导入文件,读取导入的文件内容***********
* (3:读取excel数据)读取excel文件的数据信息
* ExcelUtils.readexcell(文件路径+File.separator+newFileName, 1)
* 文件名的拼接:路径+/+新的文件名字,1
* @param filepath 文件路径
* @param startrow 读取的开始行
* @Result 返回一个二维数组（第一维放的是行，第二维放的是列表）
* @throws Exception
*/
public static String[][] readexcell(String filepath,int startrow) throws Exception{
// 判断文件是否存在
File file = new File(filepath);
if (!file.exists()) {
throw new IOException("文件" + filepath + "W不存在！");
}
//获取sheet
Sheet sheet = getSheet(filepath);
// 得到总行数
int rowNum = sheet.getLastRowNum()+1;
// 根据第一行获取列数
Row row = sheet.getRow(0);
//获取总列数
int colNum = row.getPhysicalNumberOfCells();
//根据行列创建二维数组
String[][] content = new String[rowNum-startrow][colNum];
String[] cols = null;
//通过循环，给二维数组赋值
for (int i = startrow; i < rowNum; i++) {
row = sheet.getRow(i);
cols = new String[colNum];
for (int j = 0; j < colNum; j++) {
//获取每个单元格的值
cols[j] = getCellValue(row.getCell(j));
//把单元格的值存入二维数组
content[i - startrow][j] =cols[j];
}
}
return content;
}
/**
* 根据表名获取第一个sheet
* @param path d:\\1213.xml
* @return 2003-HSSFWorkbook 2007-XSSFWorkbook
* @throws Exception
*/
public static Sheet getSheet(String file) throws Exception {
//文件后缀
String extension = file.lastIndexOf(".") == -1 ? "" : file.substring(file.lastIndexOf("."));
//创建输入流
InputStream is = new FileInputStream(file);
if (".xls".equals(extension)) {//2003
//获取工作薄
POIFSFileSystem fs = new POIFSFileSystem(is);
return new HSSFWorkbook(fs).getSheetAt(0);
} else if (".xlsx".equals(extension) || ".xlsm".equals(extension)) {
return new XSSFWorkbook(is).getSheetAt(0);
} else {
throw new IOException("文件（" + file + "）,无法识别！");
}
}
/**
* 功能:获取单元格的值
*/
public static String getCellValue(Cell cell) {
Object result = "";
if (cell != null) {
switch (cell.getCellType()) {
case Cell.CELL_TYPE_STRING:
result = cell.getStringCellValue();
break;
case Cell.CELL_TYPE_NUMERIC:
// 在excel里,日期也是数字,在此要进行判断
if(HSSFDateUtil.isCellDateFormatted(cell)){
SimpleDateFormat sdf = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");
Date date = cell.getDateCellValue();
result = sdf.format(date);
}else{
DecimalFormat df=new DecimalFormat("#");
result=df.format(cell.getNumericCellValue());
}
break;
case Cell.CELL_TYPE_BOOLEAN:
result = cell.getBooleanCellValue();
break;
case Cell.CELL_TYPE_FORMULA:
result = cell.getCellFormula();
break;
case Cell.CELL_TYPE_ERROR:
result = cell.getErrorCellValue();
break;
case Cell.CELL_TYPE_BLANK:
break;
default:
break;
}
}
return result.toString();
}
/**
* 导出
* 根据传入List数据集合导出Excel表格 生成本地excel
* @param file （输出流路径）d:\\123.xml
* @param list 任何对象类型的list（数据库直接查询出的）User（id，name，age，sex)
* @param columnNames（表头名称）(姓名、性别、年龄)
* @param columns （表头对应的列名）（name,sex,age）注意顺序
* @param sheetName（sheet名称）
*/
@SuppressWarnings("rawtypes")
public static void exportExcelByList(String file, List list,String[] columnNames, String[] columns, String sheetName) {
OutputStream fos =null;
try {
//获取输出流
fos= new FileOutputStream(file);
//创建工作薄HSSFWorkbook
HSSFWorkbook wb = new HSSFWorkbook();
//创建表单sheet
HSSFSheet sheet = wb.createSheet(sheetName);
//创建样式对象
HSSFCellStyle style = wb.createCellStyle(); // 样式对象
//style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直
//style.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 水平
//创建行--表头
HSSFRow row = sheet.createRow(0);
for (int i = 0; i < columnNames.length; i++) {
//创建列、单元格
HSSFCell cell = row.createCell(i);
cell.setCellValue(columnNames[i]);
cell.setCellStyle(style);
}
//创建数据列
for (int i = 0; i < list.size(); i++) {
Object o = list.get(i);
//创建行--数据
HSSFRow listRow = sheet.createRow(i + 1);
//循环列字段数组
for (int j = 0; j < columns.length; j++) {
//创建列
HSSFCell listCell = listRow.createCell(j);
//根据反射调用方法
Method m = o.getClass().getMethod("get" + upperStr(columns[j]));
String value = (String) m.invoke(o);
if (value != null) {
listCell.setCellValue(value);
listCell.setCellStyle(style);
} else {
listCell.setCellValue("");
listCell.setCellStyle(style);
}
sheet.autoSizeColumn(j+1, true);//自适应，从1开始
}
}
//把工作薄写入到输出流
wb.write(fos);
System.out.println("生成excel成功："+file);
} catch (Exception e) {
e.printStackTrace();
}finally {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* *************首先此方法作为导出xecel文件的方法**************
* 根据传入List数据集合导出Excel表格 返回页面选择保存路径的excel
* @param response （响应页面）
* @param list 查询的一个数据集合列表
* @param columnNames 导出后的excel文件的表头
* @param columns 对应数据库里的属性名
* @param sheetName 工作簿的名字
* @param filename 导出的文件名
*/
@SuppressWarnings("rawtypes")
public static void exportExcel(HttpServletResponse response,List list, String[] columnNames, String[] columns,String sheetName, String filename) {
OutputStream fos = null;
try {
//响应输出流，让用户自己选择保存路径
fos = getOutputStream(response, filename);
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet(sheetName);
HSSFCellStyle style = wb.createCellStyle(); // 样式对象
//style.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 垂直
//style.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 水平
HSSFRow row = sheet.createRow(0);
for (int i = 0; i < columnNames.length; i++) {
HSSFCell cell = row.createCell(i);
cell.setCellValue(columnNames[i]);
cell.setCellStyle(style);
}
for (int i = 0; i < list.size(); i++) {
HSSFRow listRow = sheet.createRow(i + 1);
Object o = list.get(i);
for (int j = 0; j < columns.length; j++) {
HSSFCell listCell = listRow.createCell(j);
Method m = o.getClass().getMethod("get" + upperStr(columns[j]));
Object value = m.invoke(o);
if (value != null) {
listCell.setCellValue(value + "");
listCell.setCellStyle(style);
} else {
listCell.setCellValue("");
listCell.setCellStyle(style);
}
sheet.autoSizeColumn(j+1, true);//自适应，从1开始
}
}
wb.write(fos);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
fos.close();
} catch (IOException e) {
e.printStackTrace();
}
}
}
/**
* 根据response获取输出流
* 2017年9月14日下午5:19:34
* @param response
* @param filename 生成文件的文件名称
* @return
* @throws UnsupportedEncodingException
* @throws IOException
*/
public static OutputStream getOutputStream(HttpServletResponse response, String filename){
OutputStream fos = null;
response.setCharacterEncoding("UTF-8");
response.reset();//清除缓存
//response.setContentType("octets/stream");
response.setContentType("application/force-download");// 设置强制下载不打开
try {
response.addHeader("Content-Disposition", "attachment;filename="+ new String((filename).getBytes("UTF-8"), "iso8859-1")+ ".xls");
fos = response.getOutputStream();
} catch (IOException e) {
e.printStackTrace();
}
return fos;
}
/**
* 把输入字符串的首字母改成大写
*
* @param str
* @return
*/
private static String upperStr(String str) {
char[] ch = str.toCharArray();
if (ch[0] >= 'a' && ch[0] <= 'z') {
ch[0] = (char) (ch[0] - 32);
}
return new String(ch);
}
public static void exportBigData(HttpServletResponse response,List list, String[] columnNames, String[] columns,String sheetName, String filename){
OutputStream os = null;
try {
response.setContentType("application/force-download"); // 设置下载类型
response.setHeader("Content-Disposition","attachment;filename=" + filename); // 设置文件的名称
os = response.getOutputStream(); // 输出流
SXSSFWorkbook wb = new SXSSFWorkbook(1000);//内存中保留 1000 条数据，以免内存溢出，其余写入 硬盘
//获得该工作区的第一个sheet
Sheet sheet1 = wb.createSheet(sheetName);
int excelRow = 0;
//标题行
Row titleRow = (Row) sheet1.createRow(excelRow++);
for (int i = 0; i < columns.length; i++) {
Cell cell = titleRow.createCell(i);
cell.setCellValue(columns[i]);
}
if (list!= null && list.size() > 0) {
for (int i = 0; i < list.size(); i++) {
//明细行
Row contentRow = (Row) sheet1.createRow(excelRow++);
List<String> reParam = (List<String>) list.get(i);
for (int j = 0; j < reParam.size(); j++) {
Cell cell = contentRow.createCell(j);
cell.setCellValue(reParam.get(j));
}
}
}
wb.write(os);
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
if (os != null) {
os.close();
}
} catch (IOException e) {
e.printStackTrace();
} // 关闭输出流
}
}
}
第二个:FileUtils
//工具类所在包名
package com.XXX.utils;
//导包
import java.io.File;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.util.UUID;
import javax.servlet.ServletOutputStream;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import org.springframework.web.multipart.MultipartFile;
public class FileUtils {
//文件上传功能调用(1:上传文件FileUtils.upload)
public static String upload(MultipartFile myfile,HttpServletRequest request) throws IllegalStateException, IOException {
//获取源文件的名称 和类型 例如 abc.jpg;
String oldname = myfile.getOriginalFilename();
String fileType = oldname.substring(oldname.lastIndexOf("."));
//文件重新命名,定义新文件名
String newName = UUID.randomUUID().toString()+fileType;
//定义文件上传路径
//获取当前项目的根路径
//D:\stsworkspace\fileUpDown\src\main\webapp
//(2:获取文件路径)String path =request.getSession().getServletContext().getRealPath("file");
String path =request.getSession().getServletContext().getRealPath("file");
//String path ="D:\\stsworkspace\\fileUpDown\\src\\main\\webapp\\files";
//创建文件
//(3:路径+/+文件名,1)
File file = new File(path+File.separator+newName);
//完成文件复制
myfile.transferTo(file);
return newName;
}
//文件下载功能
public static void downLoad(String fileName,HttpServletRequest request,HttpServletResponse response) throws IOException {
//设置http传输格式
//设置下载的文件名
response.setContentType("application/force-download");// 设置强制下载不打开
// 设置文件名
response.addHeader("Content-Disposition", "attachment;fileName=" + fileName);
//获取文件路径
String path = request.getServletContext().getRealPath("file/image");
//通过文件名获取文件,更加文件名 加文件的路径 创建文件对象
File file = new File(path+File.separator+fileName);
//获取输入流对象，
InputStream is = new FileInputStream(file);
//获取输出流对象
ServletOutputStream outputStream = response.getOutputStream();
//输入流转换为输出流对象
int b;
while((b=is.read())!=-1) {
outputStream.write(b);
}
outputStream.close();
}
}