用jsp动态输出excel文档和中文乱码问题的解决

用jsp动态输出excel文档和中文乱码问题的解决

作者：陈万飞

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。

1. 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。
   
   
2. 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));  }}

3. 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!

参考资料

http://www.mail-archive.com/[e-mail]/msg02800.html