（5）POI读取Excel内容

import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.InputStream;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
import java.util.Date;
import java.util.logging.Level;
import java.util.logging.Logger;
import org.apache.poi.hssf.usermodel.HSSFCell;
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.xssf.usermodel.XSSFCell;
import org.apache.poi.xssf.usermodel.XSSFRow;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;
import writeFileContent.ExcelUtil;

public class ExcelReader {

/**
* 读取excel03内容
* @param file excel03文件
* @return ArrayList<ArrayList<String>>
*/
public static ArrayList<ArrayList<String>> readXLS(String file){
ArrayList<ArrayList<String>> data=new ArrayList<ArrayList<String>>();
try{
InputStream is=new FileInputStream(file);
HSSFWorkbook workbook=new HSSFWorkbook(is);//创建对Excel工作簿文件的引用
//遍历每个sheet表
for (int numSheet = 0; numSheet < workbook.getNumberOfSheets(); numSheet++) {
if (null != workbook.getSheetAt(numSheet)) {
HSSFSheet sheet = workbook.getSheetAt(numSheet); //获得一个sheet
//遍历sheet表的每一行的内容
for (int rowNumOfSheet = 0; rowNumOfSheet <= sheet.getLastRowNum(); rowNumOfSheet++) {
if (null != sheet.getRow(rowNumOfSheet)) {
HSSFRow row = sheet.getRow(rowNumOfSheet); //获得一行
ArrayList<String> rowList=new ArrayList<String>();
//遍历该行每个单元格的内容
for (int cellNumOfRow = 0; cellNumOfRow <= row.getLastCellNum(); cellNumOfRow++) {
if (null != row.getCell(cellNumOfRow)) {
HSSFCell cell = row.getCell(cellNumOfRow); //获得列值
if(cell.getCellType() == HSSFCell.CELL_TYPE_NUMERIC){//数值类型
if(HSSFDateUtil.isCellDateFormatted(cell)){
DateFormat df=new SimpleDateFormat("yyyy/MM/dd");
Date date=cell.getDateCellValue();
rowList.add(df.format(date));
}else{
double value=cell.getNumericCellValue();
rowList.add(String.valueOf(value));
}
}else if(cell.getCellType() == HSSFCell.CELL_TYPE_BOOLEAN){//布尔类型
boolean bool=cell.getBooleanCellValue();
rowList.add(String.valueOf(bool));
}else {
rowList.add(cell.getStringCellValue());
}
}
}
data.add(rowList);
}
}
}
}
} catch (FileNotFoundException ex) {
Logger.getLogger(ExcelUtil.class.getName()).log(Level.SEVERE, null, ex);
} catch (IOException ex) {
Logger.getLogger(ExcelUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return data;
}

/**
* 读取excel07内容
* @param file excel07文件
* @return ArrayList<ArrayList<String>>
*/
public static ArrayList<ArrayList<String>> readXLSX(String file){
ArrayList<ArrayList<String>> data=new ArrayList<ArrayList<String>>();
try{
//构造 XSSFWorkbook 对象，file 传入文件路径
XSSFWorkbook xwb = new XSSFWorkbook(file);
//循环工作表Sheet
for(int numSheet = 0; numSheet < xwb.getNumberOfSheets(); numSheet++){
XSSFSheet sheet = xwb.getSheetAt(numSheet);
if(sheet == null){
continue;
}
//循环行Row
for(int rowNum = 0; rowNum <= sheet.getLastRowNum(); rowNum++){
XSSFRow row = sheet.getRow(rowNum);
if(row == null){
continue;
}
ArrayList<String> rowList=new ArrayList<String>();
//循环列Cell
for(int cellNum = 0; cellNum <= row.getLastCellNum(); cellNum++){
XSSFCell cell = row.getCell(cellNum);
if(cell == null){
continue;
}
if(cell.getCellType() == XSSFCell.CELL_TYPE_BOOLEAN){
boolean bool=cell.getBooleanCellValue();
rowList.add(String.valueOf(bool));
}else if(cell.getCellType() == HSSFCell.CELL_TYPE_NUMERIC){//数值类型
if(HSSFDateUtil.isCellDateFormatted(cell)){
DateFormat df=new SimpleDateFormat("yyyy/MM/dd");
Date date=cell.getDateCellValue();
rowList.add(df.format(date));
}else{
double value=cell.getNumericCellValue();
rowList.add(String.valueOf(value));
}
}else{
rowList.add(cell.getStringCellValue());
}
}
data.add(rowList);
}
}
} catch (IOException ex) {
Logger.getLogger(ExcelUtil.class.getName()).log(Level.SEVERE, null, ex);
}
return data;
}

/**
* 根据文件后缀名来判断是xls还是xlsx，从而决定用哪个方法获取excel内容
* @param file 文件
* @return 内容
*/
public static ArrayList<ArrayList<String>> read(String file){
ArrayList<ArrayList<String>> data=new ArrayList<ArrayList<String>>();
String fileType=file.substring(file.lastIndexOf(".")).toLowerCase();
switch(fileType){
case ".xls":
data=readXLS(file);
break;
case ".xlsx":
data=readXLSX(file);
break;
default:
return null;
}
return data;
}

public static void main(String args[]){
String file="";
ArrayList<ArrayList<String>> data=read(file);
if(data!=null){
for(ArrayList<String> list:data){
System.out.println(list);
}
}
}
}