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，我这里就用两篇文章分别给大家介绍下。（注意，我们这里说的数据导出可不是数据库中的数据导出！么误会啦^_^）
呵呵，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： ，我这里使用的是3.0.2版本。
将3个jar包导入到classpath下，什么？忘了怎么导包？不会吧！好，我们来写一个导出Excel的实用类（所谓实用，是指基本不用怎么修改就可以在实际项目中直接使用的！）。我一直强调做类也好，做方法也好，一定要通用性和灵活性强。下面这个类就算基本贯彻了我的这种思想。那么，熟悉许老师风格的人应该知道，这时候该要甩出一长串代码了。没错，大伙请看：
import java.util.Date;public class Student{private long id;private String name;private int age;private boolean sex;private Date birthday;public Student(){}public Student(long id, String name, int age, boolean sex, Date birthday){this.id = id;this.name = name;this.age = age;this.sex = sex;this.birthday = birthday;}public long getId(){return id;}public void setId(long id){this.id = id;}public String getName(){return name;}public void setName(String name){this.name = name;}public int getAge(){return age;}public void setAge(int age){this.age = age;}public boolean getSex(){return sex;}public void setSex(boolean sex){this.sex = sex;}public Date getBirthday(){return birthday;}public void setBirthday(Date birthday){this.birthday = birthday;}}public class Book{private int bookId;private String name;private String author;private float price;private String isbn;private String pubName;private byte[] preface;public Book(){}public Book(int bookId, String name, String author, float price,String isbn, String pubName, byte[] preface){this.bookId = bookId;this.name = name;this.author = author;this.price = price;this.isbn = isbn;this.pubName = pubName;this.preface = preface;}public int getBookId(){return bookId;}public void setBookId(int bookId){this.bookId = bookId;}public String getName(){return name;}public void setName(String name){this.name = name;}public String getAuthor(){return author;}public void setAuthor(String author){this.author = author;}public float getPrice(){return price;}public void setPrice(float price){this.price = price;}public String getIsbn(){return isbn;}public void setIsbn(String isbn){this.isbn = isbn;}public String getPubName(){return pubName;}public void setPubName(String pubName){this.pubName = pubName;}public byte[] getPreface(){return preface;}public void setPreface(byte[] preface){this.preface = preface;}}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：import java.io.BufferedInputStream;import java.io.FileInputStream;import java.io.FileNotFoundException;import java.io.FileOutputStream;import java.io.IOException;import java.io.OutputStream;import java.lang.reflect.Field;import java.lang.reflect.InvocationTargetException;import java.lang.reflect.Method;import java.text.SimpleDateFormat;import java.util.ArrayList;import java.util.Collection;import java.util.Date;import java.util.Iterator;import java.util.List;import java.util.regex.Matcher;import java.util.regex.Pattern;import javax.swing.JOptionPane;import org.apache.poi.hssf.usermodel.HSSFCell;import org.apache.poi.hssf.usermodel.HSSFCellStyle;import org.apache.poi.hssf.usermodel.HSSFClientAnchor;import org.apache.poi.hssf.usermodel.HSSFComment;import org.apache.poi.hssf.usermodel.HSSFFont;import org.apache.poi.hssf.usermodel.HSSFPatriarch;import org.apache.poi.hssf.usermodel.HSSFRichTextString;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.hssf.util.HSSFColor;/** * 利用开源组件POI3.0.2动态导出EXCEL文档 转载时请保留以下信息，注明出处！ * * @author leno * @version v1.0 * @param <T> *应用泛型，代表任意一个符合javabean风格的类 *注意这里为了简单起见，boolean型的属性xxx的get器方式为getXxx(),而不是isXxx() *byte[]表jpg格式的图片数据 */public class ExportExcel<T>{public void exportExcel(Collection<T> dataset, OutputStream out){exportExcel("测试POI导出EXCEL文档", null, dataset, out, "yyyy-MM-dd");}public void exportExcel(String[] headers, Collection<T> dataset,OutputStream out){exportExcel("测试POI导出EXCEL文档", headers, dataset, out, "yyyy-MM-dd");}public void exportExcel(String[] headers, Collection<T> dataset,OutputStream out, String pattern){exportExcel("测试POI导出EXCEL文档", headers, dataset, out, pattern);}/** * 这是一个通用的方法，利用了JAVA的反射机制，可以将放置在JAVA集合中并且符号一定条件的数据以EXCEL 的形式输出到指定IO设备上 * * @param title *表格标题名 * @param headers *表格属性列名数组 * @param dataset *需要显示的数据集合,集合中一定要放置符合javabean风格的类的对象。此方法支持的 *javabean属性的数据类型有基本数据类型及String,Date,byte[](图片数据) * @param out *与输出设备关联的流对象，可以将EXCEL文档导出到本地文件或者网络中 * @param pattern *如果有时间数据，设定输出格式。默认为"yyy-MM-dd" */@SuppressWarnings("unchecked")public void exportExcel(String title, String[] headers,Collection<T> dataset, OutputStream out, String pattern){// 声明一个工作薄HSSFWorkbook workbook = new HSSFWorkbook();// 生成一个表格HSSFSheet sheet = workbook.createSheet(title);// 设置表格默认列宽度为15个字节sheet.setDefaultColumnWidth((short) 15);// 生成一个样式HSSFCellStyle style = workbook.createCellStyle();// 设置这些样式style.setFillForegroundColor(HSSFColor.SKY_BLUE.index);style.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);style.setBorderBottom(HSSFCellStyle.BORDER_THIN);style.setBorderLeft(HSSFCellStyle.BORDER_THIN);style.setBorderRight(HSSFCellStyle.BORDER_THIN);style.setBorderTop(HSSFCellStyle.BORDER_THIN);style.setAlignment(HSSFCellStyle.ALIGN_CENTER);// 生成一个字体HSSFFont font = workbook.createFont();font.setColor(HSSFColor.VIOLET.index);font.setFontHeightInPoints((short) 12);font.setBoldweight(HSSFFont.BOLDWEIGHT_BOLD);// 把字体应用到当前的样式style.setFont(font);// 生成并设置另一个样式HSSFCellStyle style2 = workbook.createCellStyle();style2.setFillForegroundColor(HSSFColor.LIGHT_YELLOW.index);style2.setFillPattern(HSSFCellStyle.SOLID_FOREGROUND);style2.setBorderBottom(HSSFCellStyle.BORDER_THIN);style2.setBorderLeft(HSSFCellStyle.BORDER_THIN);style2.setBorderRight(HSSFCellStyle.BORDER_THIN);style2.setBorderTop(HSSFCellStyle.BORDER_THIN);style2.setAlignment(HSSFCellStyle.ALIGN_CENTER);style2.setVerticalAlignment(HSSFCellStyle.VERTICAL_CENTER);// 生成另一个字体HSSFFont font2 = workbook.createFont();font2.setBoldweight(HSSFFont.BOLDWEIGHT_NORMAL);// 把字体应用到当前的样式style2.setFont(font2);// 声明一个画图的顶级管理器HSSFPatriarch patriarch = sheet.createDrawingPatriarch();// 定义注释的大小和位置,详见文档HSSFComment comment = patriarch.createComment(new HSSFClientAnchor(0,0, 0, 0, (short) 4, 2, (short) 6, 5));// 设置注释内容comment.setString(new HSSFRichTextString("可以在POI中添加注释！"));// 设置注释作者，当鼠标移动到单元格上是可以在状态栏中看到该内容.comment.setAuthor("leno");// 产生表格标题行HSSFRow row = sheet.createRow(0);for (short i = 0; i < headers.length; i++){HSSFCell cell = row.createCell(i);cell.setCellStyle(style);HSSFRichTextString text = new HSSFRichTextString(headers[i]);cell.setCellValue(text);}// 遍历集合数据，产生数据行Iterator<T> it = dataset.iterator();int index = 0;while (it.hasNext()){index++;row = sheet.createRow(index);T t = (T) it.next();// 利用反射，根据javabean属性的先后顺序，动态调用getXxx()方法得到属性值Field[] fields = t.getClass().getDeclaredFields();for (short i = 0; i < fields.length; i++){HSSFCell cell = row.createCell(i);cell.setCellStyle(style2);Field field = fields[i];String fieldName = field.getName();String getMethodName = "get"+ fieldName.substring(0, 1).toUpperCase()+ fieldName.substring(1);try{Class tCls = t.getClass();Method getMethod = tCls.getMethod(getMethodName,new Class[]{});Object value = getMethod.invoke(t, new Object[]{});// 判断值的类型后进行强制类型转换String textValue = null;// if (value instanceof Integer) {// int intValue = (Integer) value;// cell.setCellValue(intValue);// } else if (value instanceof Float) {// float fValue = (Float) value;// textValue = new HSSFRichTextString(// String.valueOf(fValue));// cell.setCellValue(textValue);// } else if (value instanceof Double) {// double dValue = (Double) value;// textValue = new HSSFRichTextString(// String.valueOf(dValue));// cell.setCellValue(textValue);// } else if (value instanceof Long) {// long longValue = (Long) value;// cell.setCellValue(longValue);// }if (value instanceof Boolean){boolean bValue = (Boolean) value;textValue = "男";if (!bValue){textValue = "女";}}else if (value instanceof Date){Date date = (Date) value;SimpleDateFormat sdf = new SimpleDateFormat(pattern);textValue = sdf.format(date);}else if (value instanceof byte[]){// 有图片时，设置行高为60px;row.setHeightInPoints(60);// 设置图片所在列宽度为80px,注意这里单位的一个换算sheet.setColumnWidth(i, (short) (35.7 * 80));// sheet.autoSizeColumn(i);byte[] bsValue = (byte[]) value;HSSFClientAnchor anchor = new HSSFClientAnchor(0, 0,1023, 255, (short) 6, index, (short) 6, index);anchor.setAnchorType(2);patriarch.createPicture(anchor, workbook.addPicture(bsValue, HSSFWorkbook.PICTURE_TYPE_JPEG));}else{// 其它数据类型都当作字符串简单处理textValue = value.toString();}// 如果不是图片数据，就利用正则表达式判断textValue是否全部由数字组成if (textValue != null){Pattern p = Pattern.compile("^//d+(//.//d+)?$");Matcher matcher = p.matcher(textValue);if (matcher.matches()){// 是数字当作double处理cell.setCellValue(Double.parseDouble(textValue));}else{HSSFRichTextString richString = new HSSFRichTextString(textValue);HSSFFont font3 = workbook.createFont();font3.setColor(HSSFColor.BLUE.index);richString.applyFont(font3);cell.setCellValue(richString);}}}catch (SecurityException e){e.printStackTrace();}catch (NoSuchMethodException e){e.printStackTrace();}catch (IllegalArgumentException e){e.printStackTrace();}catch (IllegalAccessException e){e.printStackTrace();}catch (InvocationTargetException e){e.printStackTrace();}finally{// 清理资源}}}try{workbook.write(out);}catch (IOException e){e.printStackTrace();}}public static void main(String[] args){// 测试学生ExportExcel<Student> ex = new ExportExcel<Student>();String[] headers ={ "学号", "姓名", "年龄", "性别", "出生日期" };List<Student> dataset = new ArrayList<Student>();dataset.add(new Student(10000001, "张三", 20, true, new Date()));dataset.add(new Student(20000002, "李四", 24, false, new Date()));dataset.add(new Student(30000003, "王五", 22, true, new Date()));// 测试图书ExportExcel<Book> ex2 = new ExportExcel<Book>();String[] headers2 ={ "图书编号", "图书名称", "图书作者", "图书价格", "图书ISBN", "图书出版社", "封面图片" };List<Book> dataset2 = new ArrayList<Book>();try{BufferedInputStream bis = new BufferedInputStream(new FileInputStream("V://book.bmp"));byte[] buf = new byte[bis.available()];while ((bis.read(buf)) != -1){//}dataset2.add(new Book(1, "jsp", "leno", 300.33f, "1234567","清华出版社", buf));dataset2.add(new Book(2, "java编程思想", "brucl", 300.33f, "1234567","阳光出版社", buf));dataset2.add(new Book(3, "DOM艺术", "lenotang", 300.33f, "1234567","清华出版社", buf));dataset2.add(new Book(4, "c++经典", "leno", 400.33f, "1234567","清华出版社", buf));dataset2.add(new Book(5, "c#入门", "leno", 300.33f, "1234567","汤春秀出版社", buf));OutputStream out = new FileOutputStream("E://a.xls");OutputStream out2 = new FileOutputStream("E://b.xls");ex.exportExcel(headers, dataset, out);ex2.exportExcel(headers2, dataset2, out2);out.close();JOptionPane.showMessageDialog(null, "导出成功!");System.out.println("excel导出成功！");}catch (FileNotFoundException e){e.printStackTrace();}catch (IOException e){e.printStackTrace();}}} 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。而且同样的，拷贝一张小巧的图书图片命名为book.jpg放置到当前WEB根目录的/WEB-INF/下。部署好web工程，用浏览器访问Servlet看下效果吧！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了。好啦，祝您学习愉快！Java导出Excel弹出下载框人生就像一杯没有加糖的咖啡，喝起来是苦涩的，
