Excel,Pdf,Xml 文件操作（一）

        在实际项目中，经常需要将数据库读出的数据导入到 文件中，而现在用得最多的就是ORM工具，得出的就是一个个对象，而将这些对象中的数据写入文件还需要很多操作.   这里结合java放射技术直接将对象作为参数，然后经过反射解析得出数据然后写入文件。

1。 类设计图（运用工厂设计模式）。

Download

PdfExport

XmlExport

ExcelExport

IExport

ExportFactory

Extends

Extends

Extends

implements

implements

implements

 

 

2 。类实现

Download类提供了通用的文件下载方法并在IExport接口中声明。

/**
  * 文件下载方法
  * @param outfileName，输出显示文件名
  * @param outfile，需要下载的文件名
  * @param response
  */
     public int download(String outfileName,String outfile,HttpServletResponse response);
     /**
   * 文件下载方法
   * @param outfileName，输出显示文件名
   * @param outfile，需要下载的文件名
   * @param response
   */
     public int download(String outfileName,String outfile,WebResponse response);

Download实现：

package org.xiaohongli.common.export;

import java.io.BufferedInputStream;
import java.io.BufferedOutputStream;
import java.io.FileInputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.net.URLEncoder;

import javax.servlet.http.HttpServletResponse;

import org.apache.tapestry.util.ContentType;
import org.apache.tapestry.web.WebResponse;
import org.xiaohongli.common.Contenttype;

public class Download {
 public  int download(String outfileName, String outfile, HttpServletResponse response) {
  BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        OutputStream fos = null;
        InputStream fis = null;
        try {
            response.setContentType(Contenttype.getContentType(outfileName));
            response.setHeader("Content-disposition", "attachment;filename="
                    + URLEncoder.encode(outfileName, "utf-8"));
            java.io.File file = new java.io.File(outfile);
            fis = new FileInputStream(file);
            bis = new BufferedInputStream(fis);
            fos = response.getOutputStream();
            bos = new BufferedOutputStream(fos);
            int bytesRead = 0;
            byte[] buffer = new byte[5*1024];
            while ((bytesRead = bis.read(buffer,0,5*1024)) != -1) {
             bos.write(buffer, 0, bytesRead);//将文件发送到客户端
            }
            bos.flush() ;
        }
        catch (IOException e) {
            response.reset();
            return Util.ERROR ;
        }
        finally {
            try {
                if (fos != null) {
                    fos.close();
                }
                if (bos != null) {
                    bos.close();
                }
                if (fis != null) {
                    fis.close();
                }
                if (bis != null) {
                    bis.close();
                }
            }
            catch (IOException e) {
             return Util.ERROR ;
            }
        }
        return Util.SUCCESS ;
 }

 public  int download(String outfileName, String outfile, WebResponse response) {
  BufferedInputStream bis = null;
        BufferedOutputStream bos = null;
        OutputStream fos = null;
        InputStream fis = null;
        try {
          ContentType contentType = new ContentType(Contenttype.getContentType(outfileName));
          response.setHeader("Content-disposition", "attachment;filename="
                     + URLEncoder.encode(outfileName, "utf-8"));
          fos = response.getOutputStream(contentType) ;
            java.io.File file = new java.io.File(outfile);
            fis = new FileInputStream(file);
            bis = new BufferedInputStream(fis);
            bos = new BufferedOutputStream(fos);
            int bytesRead = 0;
            byte[] buffer = new byte[5*1024];
            while ((bytesRead = bis.read(buffer,0,5*1024)) != -1) {
             bos.write(buffer, 0, bytesRead);//将文件发送到客户端
            }
            bos.flush() ;
        }
        catch (IOException e) {
            response.reset();
            return Util.ERROR ;
        }
        finally {
            try {
                if (fos != null) {
                    fos.close();
                }
                if (bos != null) {
                    bos.close();
                }
                if (fis != null) {
                    fis.close();
                }
                if (bis != null) {
                    bis.close();
                }
            }
            catch (IOException e) {
             return Util.ERROR ;
            }
        }
        return Util.SUCCESS ;
 }
}
Contenttype类提供了解析文件类型，并获得正确的ContentType，实现

package org.xiaohongli.common;

public class Contenttype {
 public static String getContentType(String fileName) {
        String fileNameTmp = fileName.toLowerCase();
        String ret = "";
        if (fileNameTmp.endsWith("txt")) {
            ret = "text/plain";
        }
        if (fileNameTmp.endsWith("gif")) {
            ret = "image/gif";
        }
        if (fileNameTmp.endsWith("jpg")) {
            ret = "image/jpeg";
        }
        if (fileNameTmp.endsWith("jpeg")) {
            ret = "image/jpeg";
        }
        if (fileNameTmp.endsWith("jpe")) {
            ret = "image/jpeg";
        }
        if (fileNameTmp.endsWith("zip")) {
            ret = "application/zip";
        }
        if (fileNameTmp.endsWith("rar")) {
            ret = "application/rar";
        }
        if (fileNameTmp.endsWith("doc")) {
            ret = "application/msword";
        }
        if (fileNameTmp.endsWith("ppt")) {
            ret = "application/vnd.ms-powerpoint";
        }
        if (fileNameTmp.endsWith("xls")) {
            ret = "application/vnd.ms-excel";
        }
        if (fileNameTmp.endsWith("html")) {
            ret = "text/html";
        }
        if (fileNameTmp.endsWith("htm")) {
            ret = "text/html";
        }
        if (fileNameTmp.endsWith("tif")) {
            ret = "image/tiff";
        }
        if (fileNameTmp.endsWith("tiff")) {
            ret = "image/tiff";
        }
        if (fileNameTmp.endsWith("pdf")) {
            ret = "application/pdf";
        }
        return ret;
    }
}
Util.SUCCESS 和Util.ERROR是定义的两个静态常量。标识操作成功和失败。

 

未完待续。。。。。。。。。。。