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这篇文章将为大家详细讲解有关Java如何写入写出Excel，小编觉得挺实用的，因此分享给大家做个参考，希望大家阅读完这篇文章后可以有所收获。
数据原来是这样的，不同的实验有一个专门的文件夹，实验名的文件夹下有不同班级的文件夹，班级文件夹下有该班级日期文件夹，存储的是不同时间下该班做实验的数据EXCEL，原来的EXCEL中没有班级和时间，现在需要通过读取EXCEL名以及班级名来将该信息作为一列，加入到EXCEL中。
类ExcelRead：
import java.awt.List;
import java.io.ByteArrayOutputStream;
import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.text.DecimalFormat;
import java.text.SimpleDateFormat;
import java.util.ArrayList;
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;
public class ExcelRead {
String path;
public String getPath() {
return path;
}
public void setPath(String path) {
this.path = path;
}
//默认单元格内容为数字时格式
private static DecimalFormat df = new DecimalFormat("0");
// 默认单元格格式化日期字符串
private static SimpleDateFormat sdf = new SimpleDateFormat( "yyyy-MM-dd HH:mm:ss");
// 格式化数字
private static DecimalFormat nf = new DecimalFormat("0.00");
public static ArrayList<ArrayList<Object>> readExcel(File file){
if(file == null){
return null;
}
if(file.getName().endsWith("xlsx")){
//处理ecxel2007
return readExcel2007(file);
} else{
//处理ecxel2003
return readExcel2003(file);
}
}
/*
* @return 将返回结果存储在ArrayList内，存储结构与二位数组类似
* lists.get(0).get(0)表示过去Excel中0行0列单元格
*/
public static ArrayList<ArrayList<Object>> readExcel2003(File file){
try{
ArrayList<ArrayList<Object>> rowList = new ArrayList<ArrayList<Object>>();
ArrayList<Object> colList;
HSSFWorkbook wb = new HSSFWorkbook(new FileInputStream(file));
HSSFSheet sheet = wb.getSheetAt(0);
HSSFRow row;
HSSFCell cell;
Object value;
for (int i = sheet.getFirstRowNum() , rowCount = 0; rowCount < sheet.getPhysicalNumberOfRows() ; i++ ){
row = sheet.getRow(i);
colList = new ArrayList<Object>();
if(row == null){
//当读取行为空时
if(i != sheet.getPhysicalNumberOfRows()){
//判断是否是最后一行
rowList.add(colList);
}
continue;
} else{
rowCount++;
}
for ( int j = row.getFirstCellNum() ; j <= row.getLastCellNum() ;j++){
cell = row.getCell(j);
if(cell == null || cell.getCellType() == HSSFCell.CELL_TYPE_BLANK){
//当该单元格为空
if(j != row.getLastCellNum()){
//判断是否是该行中最后一个单元格
colList.add("");
}
continue;
}
switch(cell.getCellType()){
case XSSFCell.CELL_TYPE_STRING:
//System.out.println(i + "行" + j + " 列 is String type");
value = cell.getStringCellValue();
break;
case XSSFCell.CELL_TYPE_NUMERIC:
if ("@".equals(cell.getCellStyle().getDataFormatString())) {
value = df.format(cell.getNumericCellValue());
} else if ("General".equals(cell.getCellStyle()
.getDataFormatString())) {
value = nf.format(cell.getNumericCellValue());
} else {
value = sdf.format(HSSFDateUtil.getJavaDate(cell
.getNumericCellValue()));
}
// System.out.println(i + "行" + j
// + " 列 is Number type ; DateFormt:"
// + value.toString());
break;
case XSSFCell.CELL_TYPE_BOOLEAN:
//System.out.println(i + "行" + j + " 列 is Boolean type");
value = Boolean.valueOf(cell.getBooleanCellValue());
break;
case XSSFCell.CELL_TYPE_BLANK:
//System.out.println(i + "行" + j + " 列 is Blank type");
value = "";
break;
default:
//System.out.println(i + "行" + j + " 列 is default type");
value = cell.toString();
}
// end switch
colList.add(value);
}
//end for j
rowList.add(colList);
}
//end for i
return rowList;
}
catch(Exception e){
return null;
}
}
public static ArrayList<ArrayList<Object>> readExcel2007(File file){
try{
ArrayList<ArrayList<Object>> rowList = new ArrayList<ArrayList<Object>>();
ArrayList<Object> colList;
XSSFWorkbook wb = new XSSFWorkbook(new FileInputStream(file));
XSSFSheet sheet = wb.getSheetAt(0);
XSSFRow row;
XSSFCell cell;
Object value;
for (int i = sheet.getFirstRowNum() , rowCount = 0; rowCount < sheet.getPhysicalNumberOfRows() ; i++ ){
row = sheet.getRow(i);
colList = new ArrayList<Object>();
if(row == null){
//当读取行为空时
if(i != sheet.getPhysicalNumberOfRows()){
//判断是否是最后一行
rowList.add(colList);
}
continue;
} else{
rowCount++;
}
for ( int j = row.getFirstCellNum() ; j <= row.getLastCellNum() ;j++){
cell = row.getCell(j);
if(cell == null || cell.getCellType() == HSSFCell.CELL_TYPE_BLANK){
//当该单元格为空
if(j != row.getLastCellNum()){
//判断是否是该行中最后一个单元格
colList.add("");
}
continue;
}
switch(cell.getCellType()){
case XSSFCell.CELL_TYPE_STRING:
//System.out.println(i + "行" + j + " 列 is String type");
value = cell.getStringCellValue();
break;
case XSSFCell.CELL_TYPE_NUMERIC:
if ("@".equals(cell.getCellStyle().getDataFormatString())) {
value = df.format(cell.getNumericCellValue());
} else if ("General".equals(cell.getCellStyle()
.getDataFormatString())) {
value = nf.format(cell.getNumericCellValue());
} else {
value = sdf.format(HSSFDateUtil.getJavaDate(cell
.getNumericCellValue()));
}
// System.out.println(i + "行" + j
// + " 列 is Number type ; DateFormt:"
// + value.toString());
break;
case XSSFCell.CELL_TYPE_BOOLEAN:
//System.out.println(i + "行" + j + " 列 is Boolean type");
value = Boolean.valueOf(cell.getBooleanCellValue());
break;
case XSSFCell.CELL_TYPE_BLANK:
//System.out.println(i + "行" + j + " 列 is Blank type");
value = "";
break;
default:
//System.out.println(i + "行" + j + " 列 is default type");
value = cell.toString();
}
// end switch
colList.add(value);
}
//end for j
rowList.add(colList);
}
//end for i
return rowList;
}
catch(Exception e){
System.out.println("exception");
return null;
}
}
public static ArrayList getFiles(String filePath){
File root = new File(filePath);
File[]files = root.listFiles();
ArrayList filelist = new ArrayList();
for (File file:files){
if(file.isDirectory()){
filelist.addAll(getFiles(file.getAbsolutePath()));
} else{
String newpath = file.getAbsolutePath();
if(newpath.contains("交易记录")){
filelist.add(newpath);
}
}
}
return filelist;
}
public void readBook(String path4) {
String filePath = path4;
ArrayList filelist = getFiles(filePath);
ArrayList<ArrayList>resultAll = new ArrayList<ArrayList>();
for (int i = 0;i<filelist.size();i++){
String path = (String) filelist.get(i);
System.out.println(path);
ArrayList<ArrayList>result = Graph(path);
String[] path3 = path.split("\\\\");
int num = result.get(0).size();
ArrayList result2 = new ArrayList();
for (int j = 0;j<num;j++){
result2.add(path3[path3.length-2]);
}
ArrayList result3 = new ArrayList();
for (int j = 0;j<num;j++){
result3.add(path3[path3.length-3]);
}
result.add(result2);
result.add(result3);
if(resultAll.size()==0){
resultAll = result;
} else{
for (int j = 0;j<result.size();j++){
for (int k = 0;k<result.get(j).size();k++){
resultAll.get(j).add(result.get(j).get(k));
}
}
}
}
writeExcel(resultAll,"D:/a.xls");
}
public static void writeExcel(ArrayList<ArrayList> result,String path){
if(result == null){
return;
}
HSSFWorkbook wb = new HSSFWorkbook();
HSSFSheet sheet = wb.createSheet("sheet1");
for (int i = 0 ;i < result.get(0).size() ; i++){
HSSFRow row = sheet.createRow(i);
for (int j = 0; j < result.size() ; j ++){
HSSFCell cell = row.createCell((short)j);
cell.setCellValue(result.get(j).get(i).toString());
}
}
ByteArrayOutputStream os = new ByteArrayOutputStream();
try
{
wb.write(os);
}
catch (IOException e){
e.printStackTrace();
}
byte[] content = os.toByteArray();
File file = new File(path);
//Excel文件生成后存储的位置。
OutputStream fos = null;
try
{
fos = new FileOutputStream(file);
wb.write(fos);
os.close();
fos.close();
}
catch (Exception e){
e.printStackTrace();
}
}
public static DecimalFormat getDf() {
return df;
}
public static void setDf(DecimalFormat df) {
ExcelRead.df = df;
}
public static SimpleDateFormat getSdf() {
return sdf;
}
public static void setSdf(SimpleDateFormat sdf) {
ExcelRead.sdf = sdf;
}
public static DecimalFormat getNf() {
return nf;
}
public static void setNf(DecimalFormat nf) {
ExcelRead.nf = nf;
}
public static ArrayList<ArrayList> Graph(String path){
File file = new File(path);
ArrayList<ArrayList<Object>> result = ExcelRead.readExcel(file);
ArrayList<double>price = new ArrayList<double>();
//价格序列
ArrayList<String>time = new ArrayList<String>();
//时间序列
ArrayList<String>buyList = new ArrayList<String>();
//买方序列
ArrayList<String>sellList = new ArrayList<String>();
//卖方序列
ArrayList<double>vol = new ArrayList<double>();
//成交量
ArrayList<String>Share = new ArrayList<String>();
//股票名字
ArrayList<String>id = new ArrayList<String>();
ArrayList<String>Shareid = new ArrayList<String>();
for (int i = 2 ;i < result.size() ;i++){
for (int j = 0;j<result.get(i).size(); j++){
//第5列表示价格，第8列表示时间
if(j==0){
String temp = (String) result.get(i).get(j);
id.add(temp);
}
if(j==3){
String temp = (String) result.get(i).get(j);
Shareid.add(temp);
}
if(j==5){
//price.add((String) result.get(i).get(j));
String temp = (String) result.get(i).get(j);
String[] units = temp.split("￥");
price.add(double.valueOf(units[1]));
}
if(j==7){
String temp = (String) result.get(i).get(j);
time.add(temp);
// time.add((String) result.get(i).get(j));
}
if(j==1){
buyList.add((String) result.get(i).get(j));
}
if(j==2){
sellList.add((String) result.get(i).get(j));
}
if(j==6){
vol.add(double.valueOf((String)result.get(i).get(j)));
}
if(j==4){
Share.add((String)result.get(i).get(j));
}
}
}
ArrayList<ArrayList>resultList = new ArrayList<ArrayList>();
resultList.add(Shareid);
resultList.add(id);
resultList.add(buyList);
resultList.add(sellList);
resultList.add(Share);
resultList.add(price);
resultList.add(vol);
resultList.add(time);
return resultList;
}
}readExcelBook（做可视化窗口的）：
import java.awt.EventQueue;
import javax.swing.JFileChooser;
import javax.swing.JFrame;
import javax.swing.GroupLayout;
import javax.swing.JLabel;
import javax.swing.GroupLayout.Alignment;
import javax.swing.JButton;
import javax.swing.JTextField;
import java.awt.event.ActionListener;
import java.awt.event.ActionEvent;
import java.io.File;
public class readExcelBook {
private JFrame frame;
private JTextField textField;
/**
* Launch the application.
*/
public static void main(String[] args) {
EventQueue.invokeLater(new Runnable() {
public void run() {
try {
readExcelBook window = new readExcelBook();
window.frame.setVisible(true);
}
catch (Exception e) {
e.printStackTrace();
}
}
}
);
}
/**
* Create the application.
*/
public readExcelBook() {
initialize();
}
/**
* Initialize the contents of the frame.
*/
private void initialize() {
frame = new JFrame();
frame.setBounds(100, 100, 450, 300);
frame.setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
JButton button = new JButton("\u9009\u62E9\u6587\u4EF6");
button.addActionListener(new ActionListener() {
public void actionPerformed(ActionEvent e) {
JFileChooser jfc=new JFileChooser();
jfc.setFileSelectionMode(JFileChooser.FILES_AND_DIRECTORIES );
jfc.showDialog(new JLabel(), "选择");
File file=jfc.getSelectedFile();
String path = file.getAbsolutePath();
textField.setText(path);
ExcelRead er = new ExcelRead();
er.readBook(path);
}
}
);
textField = new JTextField();
textField.setColumns(10);
JLabel lbldaxls = new JLabel("\u5199\u5165\u4E86D\u76D8\u4E0B\u7684a.xls\u54C8");
GroupLayout groupLayout = new GroupLayout(frame.getContentPane());
groupLayout.setHorizontalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addGap(26)
.addGroup(groupLayout.createParallelGroup(Alignment.LEADING)
.addComponent(lbldaxls)
.addComponent(textField, GroupLayout.PREFERRED_SIZE, 295, GroupLayout.PREFERRED_SIZE)
.addComponent(button))
.addContainerGap(113, short.MAX_VALUE))
);
groupLayout.setVerticalGroup(
groupLayout.createParallelGroup(Alignment.LEADING)
.addGroup(groupLayout.createSequentialGroup()
.addGap(31)
.addComponent(button)
.addGap(18)
.addComponent(textField, GroupLayout.PREFERRED_SIZE, GroupLayout.DEFAULT_SIZE, GroupLayout.PREFERRED_SIZE)
.addGap(35)
.addComponent(lbldaxls)
.addContainerGap(119, short.MAX_VALUE))
);
frame.getContentPane().setLayout(groupLayout);
}
}运行结果：
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