java使用poi实现大数据量导出为EXCEL
总体的实现思想为：
每次查询出2w数据，并写入到临时文件
然后把这些文件写入到一个EXCEL里边，或者把这些文件压缩为zip文件，然后把Zip文件提供给下载(这里使用zip打包是因为，在Linux上也能进行Zip打包)。
//这个zip打包工具类
package net.szh.zip;
import java.io.File;
import org.apache.tools.ant.Project;
import org.apache.tools.ant.taskdefs.Zip;
import org.apache.tools.ant.types.FileSet;
public class ZipCompressorByAnt {
private File zipFile;
public ZipCompressorByAnt(String pathName) {
zipFile = new File(pathName);
}
public void compress(String srcPathName) {
File srcdir = new File(srcPathName);
if (!srcdir.exists())
throw new RuntimeException(srcPathName + "不存在！");
Project prj = new Project();
Zip zip = new Zip();
zip.setProject(prj);
zip.setDestFile(zipFile);
FileSet fileSet = new FileSet();
fileSet.setProject(prj);
fileSet.setDir(srcdir);
//fileSet.setIncludes("**/*.java"); 包括哪些文件或文件夹 eg:zip.setIncludes("*.java");
//fileSet.setExcludes(...); 排除哪些文件或文件夹
zip.addFileset(fileSet);
zip.execute();
}
}业务处理
import java.util.Map;
import com.eos.common.transaction.ITransactionManager;
import com.eos.common.transaction.TransactionManagerFactory;
import com.eos.system.annotation.Bizlet;
import com.pns.framework.dao.Dao;
import com.pns.framework.execl.Excel;
import com.pns.framework.filepath.ExportExeclUtil;
import com.pns.framework.filepath.FilePath;
import commonj.sdo.DataObject;
@Bizlet("")
public class Aeanalysis {
private ExportExeclUtil util= new ExportExeclUtil();
/**
* 变电站
*
*/
@Bizlet("")
public String export4boassets(Map<String,String> map,String nameSqlid) {
String tempFileName ;
String fileName ;
ITransactionManager manager = TransactionManagerFactory.getTransactionManager();
DataObject[] objects={};
try {
/**
*在这儿得到总共的条数，再除每个文件的条数，得到需要多少个文件，求余如果不为零，
*则需要循环的次数即为文件数，如果不为零则为文件数+1；文件写完之后进行压缩
*，把压缩文件的地址返回到流的jsp中。
*/
tempFileName = FilePath.getTempFilePath("02_02_01.xls");//零时文件 例：xxx.xls
fileName = FilePath.getTemplatePath("aeanalysis/uic01_001.xls");//模板文件 例： pamanagement/uic02_001_004.xls
manager.begin();
objects = Dao.query(nameSqlid, map);
manager.commit();
//变电站标识 电网变电站标识 变电站名称 电压等级 变电站地址 管理单位 运行状态 变电站标识 变电站业务系统ID 变电站名称 电压等级 变电站地址 管理单位 运行状态 备注
String[] fieldArrStr = new String[] {"SUBS_ID", "PMS_SUBS_ID", "SUBS_NAME", "VOLT_CODE","SUBS_ADDR","ORG_NAME","RUN_STATUS","PMS_ID","PMS_GLOBEID",
"PMS_SUBS_NAME","PMS_VOLT_CODE","PMS_SUBS_ADDR","PMS_ORG_NAME","PMS_RUN_STATUS",
"REMARK"};
util.exportExcelToTemp(fileName, 2, objects, fieldArrStr, tempFileName);
} catch (RuntimeException e) {
manager.rollback();
tempFileName="ex";
}
return tempFileName;
}
/**
* 生成只有数据的execl到临时文件夹下
*
* @param args
* @throws IOException
*/
public boolean exportExcelToTemp(String temFile,int beginRowIndex,Object[] objects,String[] fieldArrStr,String tempPath) {
boolean flag;
FileOutputStream fos = null;
try {
this.getWorkBook(temFile);
this.getSheet();
this.setDataRow(beginRowIndex, objects, fieldArrStr);
fos = new FileOutputStream(tempPath);
workBook.write(fos);
flag=true;
} catch (IOException e) {
// TODO 自动生成 catch 块
flag=false;
} finally {
try {
if(fos != null){
fos.close();
}
} catch (IOException e) {
// TODO 自动生成 catch 块
e.printStackTrace();
}
}
return flag;
}
}
jsp文件
<%@page pageEncoding="UTF-8"
%><%@page contentType="text/plain; charset=utf-8"
%><%@page import="org.apache.commons.fileupload.*"
%><%@page import="java.net.URLEncoder"
%><%@page import="java.io.BufferedOutputStream"
%><%@page import="java.io.FileInputStream"
%><%@page import="java.io.IOException"
%><%@page import="java.util.Date"
%><%@page import="java.text.SimpleDateFormat"
%>
<%String path =request.getParameter("path");
String filename=request.getParameter("filename");
//String time=request.getParameter("time");
response.reset();//可以加也可以不加
response.setContentType("application/x-download");
filename = URLEncoder.encode(filename,"UTF-8");
SimpleDateFormat df = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");//设置日期格式
String dd=df.format(new Date());
//System.out.println(dd);// new Date()为获取当前系统时间
response.addHeader("Content-Disposition", "attachment; filename=" +dd+"_"+filename);
BufferedOutputStream bos = null;
FileInputStream fis = null;
try {
fis = new FileInputStream(path);
bos = new BufferedOutputStream(response.getOutputStream());
byte[] buffer = new byte[1024];
while(fis.read(buffer) != -1){
bos.write(buffer);
}
response.flushBuffer();
out.clear();
}catch(IOException e) {
e.printStackTrace();
}finally {
fis.close();
bos.close();
}%>