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:http://poi.apache.org/ ,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!
将ExportExcel类的main方法改成public void test(),OutputStream out = new FileOutputStream("E://a.xls");这边可以对应Servlet适当改下路径,Servlet代码如下:
public class ExcelServlet extends HttpServlet { public void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException { (new ExportExcel()).test(); String str = "a.xls"; //String path = request.getSession().getServletContext().getRealPath(str); download("E://a.xls", response); } private void download(String path, HttpServletResponse response) { try { // path是指欲下载的文件的路径。 File file = new File(path); // 取得文件名。 String filename = file.getName(); // 以流的形式下载文件。 InputStream fis = new BufferedInputStream(new FileInputStream(path)); byte[] buffer = new byte[fis.available()]; fis.read(buffer); fis.close(); // 清空response response.reset(); // 设置response的Header response.addHeader("Content-Disposition", "attachment;filename=" + new String(filename.getBytes())); response.addHeader("Content-Length", "" + file.length()); OutputStream toClient = new BufferedOutputStream( response.getOutputStream()); response.setContentType("application/vnd.ms-excel;charset=gb2312"); toClient.write(buffer); toClient.flush(); toClient.close(); } catch (IOException ex) { ex.printStackTrace(); } } }