1.Apache POI简介
Apache POI是Apache软件基金会的开放源码函式库，POI提供API给Java程式对Microsoft Office格式档案读和写的功能。 .NET的开发人员则可以利用NPOI (POI for .NET) 来存取 POI 的功能。
2.POI结构
HSSF － 提供读写Microsoft Excel XLS格式档案的功能。
XSSF － 提供读写Microsoft Excel OOXML XLSX格式档案的功能。
HWPF － 提供读写Microsoft Word DOC格式档案的功能。
HSLF － 提供读写Microsoft PowerPoint格式档案的功能。
HDGF － 提供读Microsoft Visio格式档案的功能。
HPBF － 提供读Microsoft Publisher格式档案的功能。
HSMF － 提供读Microsoft Outlook格式档案的功能。
参考实例
在web开发中，有一个经典的功能，就是数据的导入导出。特别是数据的导出，在生产管理或者财务系统中用的非常普遍，因为这些系统经常要做一些报表打印的工作。而数据导出的格式一般是EXCEL或者PDF
首先我们来导出EXCEL格式的文件吧。现在主流的操作Excel文件的开源工具有很多,用得比较多的就是Apache的POI及JExcelAPI。这里我们用Apache POI！我们先去Apache的大本营下载POI的jar包：http://poi.apache.org/ 或者从我附件下载
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package org.leno.export.util;
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import java.util.Date;
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public class Student {
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private long id;
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private String name;
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private int age;
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private boolean sex;
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private Date birthday;
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public Student() {
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super();
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}
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public Student(long id, String name, int age, boolean sex, Date birthday) {
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super();
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this.id = id;
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this.name = name;
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this.age = age;
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this.sex = sex;
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this.birthday = birthday;
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}
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public long getId() {
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return id;
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}
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public void setId(long id) {
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this.id = id;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public int getAge() {
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return age;
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}
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public void setAge(int age) {
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this.age = age;
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}
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public boolean getSex() {
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return sex;
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}
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public void setSex(boolean sex) {
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this.sex = sex;
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}
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public Date getBirthday() {
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return birthday;
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}
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public void setBirthday(Date birthday) {
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this.birthday = birthday;
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}
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}
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package org.leno.export.util;
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public class Book {
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private int bookId;
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private String name;
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private String author;
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private float price;
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private String isbn;
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private String pubName;
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private byte[] preface;
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public Book() {
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super();
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}
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public Book(int bookId, String name, String author, float price,
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String isbn, String pubName, byte[] preface) {
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super();
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this.bookId = bookId;
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this.name = name;
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this.author = author;
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this.price = price;
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this.isbn = isbn;
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this.pubName = pubName;
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this.preface = preface;
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}
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public int getBookId() {
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return bookId;
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}
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public void setBookId(int bookId) {
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this.bookId = bookId;
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}
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public String getName() {
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return name;
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}
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public void setName(String name) {
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this.name = name;
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}
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public String getAuthor() {
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return author;
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}
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public void setAuthor(String author) {
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this.author = author;
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}
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public float getPrice() {
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return price;
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}
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public void setPrice(float price) {
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this.price = price;
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}
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public String getIsbn() {
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return isbn;
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}
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public void setIsbn(String isbn) {
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this.isbn = isbn;
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}
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public String getPubName() {
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return pubName;
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}
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public void setPubName(String pubName) {
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this.pubName = pubName;
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}
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public byte[] getPreface() {
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return preface;
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}
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public void setPreface(byte[] preface) {
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this.preface = preface;
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}
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}
上面这两个类一目了然，就是两个简单的javabean风格的类。再看下面真正的重点类：
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package org.leno.export.util;
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import java.io.*;
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import java.lang.reflect.*;
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import java.util.*;
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import java.util.regex.Matcher;
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import java.util.regex.Pattern;
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import java.text.SimpleDateFormat;
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import javax.swing.JOptionPane;
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import org.apache.poi.hssf.usermodel.*;
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import org.apache.poi.hssf.util.HSSFColor;
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public class ExportExcel<T> {
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public void exportExcel(Collection<T> dataset, OutputStream out) {
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exportExcel("测试POI导出EXCEL文档", null, dataset, out, "yyyy-MM-dd");
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}
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public void exportExcel(String[] headers, Collection<T> dataset,
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OutputStream out) {
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exportExcel("测试POI导出EXCEL文档", headers, dataset, out, "yyyy-MM-dd");
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}
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public void exportExcel(String[] headers, Collection<T> dataset,
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OutputStream out, String pattern) {
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exportExcel("测试POI导出EXCEL文档", headers, dataset, out, pattern);
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}
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@SuppressWarnings("unchecked")
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public void exportExcel(String title, String[] headers,
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Collection<T> dataset, OutputStream out, String pattern) {
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HSSFWorkbook workbook = new HSSFWorkbook();
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HSSFSheet sheet = workbook.createSheet(title);
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sheet.setDefaultColumnWidth(15);
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HSSFCellStyle style = workbook.createCellStyle();
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style.setFillForegroundColor(HSSFColor.SKY_BLUE.index);
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style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
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style.setBorderBottom(HSSFCellStyle.BORDER_THIN);
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style.setBorderLeft(HSSFCellStyle.BORDER_THIN);
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style.setBorderRight(HSSFCellStyle.BORDER_THIN);
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style.setBorderTop(HSSFCellStyle.BORDER_THIN);
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style.setAlignment(HSSFCellStyle.ALIGN_CENTER);
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HSSFFont font = workbook.createFont();
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font.setColor(HSSFColor.VIOLET.index);
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font.setFontHeightInPoints((short) 12);
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font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);
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style.setFont(font);
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HSSFCellStyle style2 = workbook.createCellStyle();
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style2.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);
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style2.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);
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style2.setBorderBottom(HSSFCellStyle.BORDER_THIN);
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style2.setBorderLeft(HSSFCellStyle.BORDER_THIN);
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style2.setBorderRight(HSSFCellStyle.BORDER_THIN);
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style2.setBorderTop(HSSFCellStyle.BORDER_THIN);
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style2.setAlignment(HSSFCellStyle.ALIGN_CENTER);
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style2.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);
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HSSFFont font2 = workbook.createFont();
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font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);
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style2.setFont(font2);
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HSSFPatriarch patriarch = sheet.createDrawingPatriarch();
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HSSFComment comment = patriarch.createComment(new HSSFClientAnchor(0,
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0, 0, 0, (short) 4, 2, (short) 6, 5));
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comment.setString(new HSSFRichTextString("可以在POI中添加注释！"));
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comment.setAuthor("leno");
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HSSFRow row = sheet.createRow(0);
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for (int i = 0; i < headers.length; i++) {
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HSSFCell cell = row.createCell(i);
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cell.setCellStyle(style);
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HSSFRichTextString text = new HSSFRichTextString(headers[i]);
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cell.setCellValue(text);
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}
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Iterator<T> it = dataset.iterator();
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int index = 0;
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while (it.hasNext()) {
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index++;
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row = sheet.createRow(index);
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T t = (T) it.next();
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Field[] fields = t.getClass().getDeclaredFields();
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for (int i = 0; i < fields.length; i++) {
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HSSFCell cell = row.createCell(i);
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cell.setCellStyle(style2);
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Field field = fields[i];
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String fieldName = field.getName();
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String getMethodName = "get"
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+ fieldName.substring(0, 1).toUpperCase()
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+ fieldName.substring(1);
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try {
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Class tCls = t.getClass();
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Method getMethod = tCls.getMethod(getMethodName,
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new Class[] {});
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Object value = getMethod.invoke(t, new Object[] {});
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String textValue = null;
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if (value instanceof Boolean) {
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boolean bValue = (Boolean) value;
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textValue = "男";
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if (!bValue) {
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textValue = "女";
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}
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} else if (value instanceof Date) {
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Date date = (Date) value;
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SimpleDateFormat sdf = new SimpleDateFormat(pattern);
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textValue = sdf.format(date);
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} else if (value instanceof byte[]) {
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row.setHeightInPoints(60);
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sheet.setColumnWidth(i, (short) (35.7 * 80));
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byte[] bsValue = (byte[]) value;
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HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0,
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1023, 255, (short) 6, index, (short) 6, index);
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anchor.setAnchorType(2);
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patriarch.createPicture(anchor, workbook.addPicture(
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bsValue, HSSFWorkbook.PICTURE_TYPE_JPEG));
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} else {
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textValue = value.toString();
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}
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if (textValue != null) {
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Pattern p = Pattern.compile("^//d+(//.//d+)?{1}quot;");
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Matcher matcher = p.matcher(textValue);
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if (matcher.matches()) {
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cell.setCellValue(Double.parseDouble(textValue));
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} else {
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HSSFRichTextString richString = new HSSFRichTextString(
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textValue);
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HSSFFont font3 = workbook.createFont();
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font3.setColor(HSSFColor.BLUE.index);
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richString.applyFont(font3);
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cell.setCellValue(richString);
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}
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}
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} catch (SecurityException e) {
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e.printStackTrace();
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} catch (NoSuchMethodException e) {
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e.printStackTrace();
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} catch (IllegalArgumentException e) {
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e.printStackTrace();
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} catch (IllegalAccessException e) {
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e.printStackTrace();
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} catch (InvocationTargetException e) {
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e.printStackTrace();
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} finally {
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}
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}
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}
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try {
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workbook.write(out);
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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public static void main(String[] args) {
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ExportExcel<Student> ex = new ExportExcel<Student>();
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String[] headers = { "学号", "姓名", "年龄", "性别", "出生日期" };
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List<Student> dataset = new ArrayList<Student>();
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dataset.add(new Student(10000001, "张三", 20, true, new Date()));
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dataset.add(new Student(20000002, "李四", 24, false, new Date()));
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dataset.add(new Student(30000003, "王五", 22, true, new Date()));
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ExportExcel<Book> ex2 = new ExportExcel<Book>();
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String[] headers2 = { "图书编号", "图书名称", "图书作者", "图书价格", "图书ISBN",
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"图书出版社", "封面图片" };
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List<Book> dataset2 = new ArrayList<Book>();
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try {
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BufferedInputStream bis = new BufferedInputStream(
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new FileInputStream("book.jpg"));
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byte[] buf = new byte[bis.available()];
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while ((bis.read(buf)) != -1) {
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}
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dataset2.add(new Book(1, "jsp", "leno", 300.33f, "1234567",
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"清华出版社", buf));
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dataset2.add(new Book(2, "java编程思想", "brucl", 300.33f, "1234567",
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"阳光出版社", buf));
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dataset2.add(new Book(3, "DOM艺术", "lenotang", 300.33f, "1234567",
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"清华出版社", buf));
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dataset2.add(new Book(4, "c++经典", "leno", 400.33f, "1234567",
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"清华出版社", buf));
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dataset2.add(new Book(5, "c#入门", "leno", 300.33f, "1234567",
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"汤春秀出版社", buf));
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OutputStream out = new FileOutputStream("D://a.xls");
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OutputStream out2 = new FileOutputStream("D://b.xls");
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ex.exportExcel(headers, dataset, out);
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ex2.exportExcel(headers2, dataset2, out2);
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out.close();
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JOptionPane.showMessageDialog(null, "导出成功!");
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System.out.println("excel导出成功！");
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} catch (FileNotFoundException e) {
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e.printStackTrace();
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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}
不行，头有点晕^_^。呵呵，又是泛型，又是反射，又是正则表达式，又是重载,还有多参数列表和POI API。一下子蹦出来，实在让人吃不消。不管了，顶住看效果先。在本地运行后，我们发现在E://下生成了两份excel文件：学生记录和图书记录，并且中文，数字，颜色，日期，图片等等一且正常。恩，太棒了。有人看到这里开始苦脸了：喂，我怎么一运行就报错啊！呵呵，看看什么错吧！哦，找不到文件，也就是说你没有book.jpg嘛。好，拷贝一张小巧的图书图片命名为book.jpg放置到当前工程下吧。注意，您千万别把张桌面大小的图片丢进去了^_^！看到效果了吧。现在我们再来简单梳理一下代码，实际上上面就做了一个导出excel的方法和一个本地测试main()方法。并且代码的结构也很清晰，只是涉及的知识点稍微多一点。大家细心看看注释，结合要完成的功能，应该没有太大问题的。好啦，吃杯茶，擦把汗，总算把这个类消化掉，你又进步了。咦，你不是说是在WEB环境下导出的吗？别急，因为导出就是一个下载的过程。我们只需要在服务器端写一个Jsp或者Servlet组件完成输出excel到浏览器客户端的工作就好了。我们以Servlet为例，还是看代码吧：
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package org.leno.export.util;
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import java.io.*;
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import java.util.ArrayList;
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import java.util.List;
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import javax.servlet.ServletException;
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import javax.servlet.http.HttpServletRequest;
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import javax.servlet.http.HttpServletResponse;
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public class Export extends javax.servlet.http.HttpServlet {
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static final long serialVersionUID = 1L;
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protected void doGet(HttpServletRequest request,
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HttpServletResponse response) throws ServletException, IOException {
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File file = new File(getServletContext()
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.getRealPath("WEB-INF/book.jpg"));
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response.setContentType("octets/stream");
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response.addHeader("Content-Disposition",
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"attachment;filename=test.xls");
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ExportExcel<Book> ex = new ExportExcel<Book>();
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String[] headers = { "图书编号", "图书名称", "图书作者", "图书价格", "图书ISBN", "图书出版社",
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"封面图片" };
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List<Book> dataset = new ArrayList<Book>();
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try {
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BufferedInputStream bis = new BufferedInputStream(
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new FileInputStream(file));
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byte[] buf = new byte[bis.available()];
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while ((bis.read(buf)) != -1) {
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}
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dataset.add(new Book(1, "jsp", "leno", 300.33f, "1234567", "清华出版社",
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buf));
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dataset.add(new Book(2, "java编程思想", "brucl", 300.33f, "1234567",
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"阳光出版社", buf));
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dataset.add(new Book(3, "DOM艺术", "lenotang", 300.33f, "1234567",
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"清华出版社", buf));
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dataset.add(new Book(4, "c++经典", "leno", 400.33f, "1234567",
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"清华出版社", buf));
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dataset.add(new Book(5, "c#入门", "leno", 300.33f, "1234567",
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"汤春秀出版社", buf));
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OutputStream out = response.getOutputStream();
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ex.exportExcel(headers, dataset, out);
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out.close();
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System.out.println("excel导出成功！");
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} catch (FileNotFoundException e) {
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e.printStackTrace();
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} catch (IOException e) {
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e.printStackTrace();
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}
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}
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protected void doPost(HttpServletRequest request,
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HttpServletResponse response) throws ServletException, IOException {
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doGet(request, response);
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}
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}
写完之后，如果您不是用eclipse工具生成的Servlet,千万别忘了在web.xml上注册这个Servelt。我用的是Eclipse工具生成的servlet，自动注册了servlet，注册内容如下：
<servlet>
<servlet-name>Export</servlet-name>
<servlet-class>org.leno.export.util.Export</servlet-class>
</servlet>
<servlet-mapping>
<servlet-name>Export</servlet-name>
<url-pattern>/servlet/Export</url-pattern>
</servlet-mapping>
我的访问地址是：http://localhost:8080/export/servlet/Export。看看是不是下载成功了。呵呵，您可以将下载到本地的excel报表用打印机打印出来，这样您就大功告成了。完事了我们就思考：我们发现，我们做的方法，不管是本地调用，还是在WEB服务器端用Servlet调用；不管是输出学生列表，还是图书列表信息，代码都几乎一样，而且这些数据我们很容器结合后台的DAO操作数据库动态获取。恩，类和方法的通用性和灵活性开始有点感觉
生成的两个excel文档内容分别如下，第一个是测试学生，第二个是测试图书。
这张有空姐为我们加油，亚麻带
