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/poi-user@jakarta.apache.org/msg02800.html