JSP动态输出Excel及中文乱码的解决

  最近在网上看到一个用Java来操纵excel的open source,在weblogic上试用了一下,觉得很不错,特此向大家推荐一下。

  首先去http://www.andykhan.com/jexcelapi/index.html下载最新的JExcelApi,把jxl.jar置于你的classpath中。

  写一个JavaBean,利用JExcelApi来动态生成excel文档,我这里写一个最简单的,示意性的。复杂的你可能还要查询数据库什么的。

///////////////////////////Test.Java///////////////////////////////////////////
package com.jagie.test;
import Java.io.*;
import jxl.*;
import jxl.write.*;
import jxl.format.*;
import Java.util.*;
import Java.awt.Color;

public class Test{
 public static void writeExcel(OutputStream os) throws Exception {
  jxl.write.WritableWorkbook wwb = Workbook.createWorkbook(os);
  jxl.write.WritableSheet ws = wwb.createSheet("TestSheet1", 0);
  jxl.write.Label labelC = new jxl.write.Label(0, 0, "我爱中国");
  ws.addCell(labelC);
  jxl.write.WritableFont wfc = new jxl.write.WritableFont(WritableFont.ARIAL,20, WritableFont.BOLD, false,
  UnderlineStyle.NO_UNDERLINE, jxl.format.Colour.GREEN);
  jxl.write.WritableCellFormat wcfFC = new jxl.write.WritableCellFormat(wfc);
  wcfFC.setBackground(jxl.format.Colour.RED);
  labelC = new jxl.write.Label(6, 0, "中国爱我",wcfFC);
  ws.addCell(labelC);
  //写入Exel工作表
  wwb.write();
  //关闭Excel工作薄对象
  wwb.close();
 }

 //最好写一个这样的main方法来测试一下你的这个class是否写好了。
 public static void main(String[] args)throws Exception{
  File f=new File("kk.xls");
  f.createNewFile();
  writeExcel(new FileOutputStream(f));
 }
}

  写一个jsp,来利用Test这个Javabean输出excel文档。

///////////////////////////test_excel.jsp//////////////////////////

<%@page import="com.jagie.test.Test" %>
<%
 response.reset();
 response.setContentType("application/vnd.ms-excel");
 Test.writeExcel(response.getOutputStream());
%>

  这样就大功告成了,你用ie访问test_excel.jsp就能在ie里面打开动态生成的excel文档了。一点乱码也没有。

  也许有人会问:response.reset();可不可以不要这一句,我的建议是一定要写,除非你能保证response的buffer里面没有别的东西。

  还有人也许会问:我在jsp开头加上<%@page contentType="application/vnd.ms-excel;charset=GBK" %>这一句,去掉response.setContentType("application/vnd.ms-excel");行不行?回答这个问题很简单,就是查看jsp服务器编译jsp后生成的Java代码,如果改成这样,我的welogic7编译test_excel.jsp后生成的Java文件的示意性代码是这样的:

public void _jspService(Javax.servlet.http.HttpServletRequest request,
Javax.servlet.http.HttpServletResponse response) throws Java.io.IOException,
Javax.servlet.ServletException {

 // declare and set well-known variables:
 Javax.servlet.ServletConfig config = getServletConfig();
 Javax.servlet.ServletContext application = config.getServletContext();
 Javax.servlet.jsp.tagext.Tag _activeTag = null;
 // variables for Tag extension protocol

 Object page = this;
 Javax.servlet.jsp.JspWriter out;
 Javax.servlet.jsp.PageContext pageContext =
 Javax.servlet.jsp.JspFactory.getDefaultFactory().getPageContext(this,
 request, response, null, true, 8192, true);

 response.setHeader("Content-Type", "application/vnd.ms-excel; charset=GBK");
 out = pageContext.getOut();
 JspWriter _originalOut = out;

 Javax.servlet.http.HttpSession session = request.getSession(true);

 try { // error page try block
  response.setContentType("application/vnd.ms-excel;charset=GBK");
  out.print("/r/n/r/n/r/n/r/n");
  out.print("/r/n");
  //[ /test_excel.jsp; Line: 6]
  response.reset(); //[ /test_excel.jsp; Line: 7]
  //response.setContentType("application/vnd.ms-excel");
  //[ /test_excel.jsp; Line: 8]
  Test.writeExcel(response.getOutputStream()); //[ /test_excel.jsp; Line: 9]
  } catch (Throwable __ee) {
   while (out != null && out != _originalOut) out = pageContext.popBody();
  ((weblogic.servlet.jsp.PageContextImpl)pageContext).handlePageException((Throwable)__ee);
 }

 //before final close brace...
}

  很明显,屏蔽response.setContentType("application/vnd.ms-excel");后,在Test.writeExcel(response.getOutputStream());之前,response.reset(); 之后没有设置response contenttype的正确类型,当然输出为乱码了。而正确输出excel的jsp的编译后源码是这样的:

public void _jspService(Javax.servlet.http.HttpServletRequest request,
Javax.servlet.http.HttpServletResponse response) throws Java.io.IOException,
Javax.servlet.ServletException
{
 // declare and set well-known variables:
 Javax.servlet.ServletConfig config = getServletConfig();
 Javax.servlet.ServletContext application = config.getServletContext();
 Javax.servlet.jsp.tagext.Tag _activeTag = null;
 // variables for Tag extension protocol

 Object page = this;
 Javax.servlet.jsp.JspWriter out;
 Javax.servlet.jsp.PageContext pageContext =
  Javax.servlet.jsp.JspFactory.getDefaultFactory().getPageContext(this, request, response, null, true, 8192, true);

 out = pageContext.getOut();
 JspWriter _originalOut = out;

 Javax.servlet.http.HttpSession session = request.getSession(true);

 try { // error page try block
  out.print("/r/n");
  //[ /test_excel.jsp; Line: 2]
  response.reset(); //[ /test_excel.jsp; Line: 3]
  response.setContentType("application/vnd.ms-excel"); //[ /test_excel.jsp; Line: 4]
  Test.writeExcel(response.getOutputStream()); //[ /test_excel.jsp; Line: 5]
 } catch (Throwable __ee) {
  while (out != null && out != _originalOut) out = pageContext.popBody();
  ((weblogic.servlet.jsp.PageContextImpl)pageContext).handlePageException((Throwable)__ee);
 }

  //before final close brace...
}

  大家可以看到在response.reset();之后,Test.writeExcel(response.getOutputStream());之前正确的设置了response的输出内容。所以输出就正常了。

  最后,希望这篇文章能对你有所启发,如有错误之处,敬请批评指正!

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