数据库导出CSV格式，并压缩成ZIP的形式导出

因为Excel导出会导致内存溢出，所以以CSV格式导出。

以下实现的功能：从数据读取数，以CSV格式导出，并压缩成ZIP，让用户下载。下面是一次导出的文件是6万条，超过6万条的，自动生成第二个文件。这个是客户的要求，一次导出一个文件其实更方便。曾经尝试过，下载百万千万条数据生成CSV格式，是不会内存溢出的。

不足之处有两个地方，CSV格式下载到本地，用户提出，一定要可以自己选路径，那没办法，本来都已经下载到本地了，只好再压缩一遍让客户自己选了。

第二，本模块不是通用的。做了一个通用的模块，但是因为每次取多少个字段不确定，只是在while里加for循环来实现，所以效率几何倍数的递减。

实现之前要导入两三个jar文件：ant.jar，commons-compress-1.3.jar，opencsv-1.8.jar。

示例下载地址：

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.sql.CallableStatement;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 import javax.servlet.http.HttpServletResponse;
 import org.apache.tools.zip.ZipEntry;
 import org.apache.tools.zip.ZipOutputStream;
 import oracle.jdbc.OracleTypes;
 import au.com.bytecode.opencsv.CSVWriter;


 /**
  * @title
  * @description Action
  * @copyright Copyright (c) 2012
  * @author painarthur
  * @version 1.0
  */

 public class Ncp_fhyDAO {

 public void exportCsv(HttpServletResponse response,int resultCountAll,String path,String csvExportIllustrate,
         int page, int pageSize,String p_cswjg_dm,String p_csssq
         ,String p_cHymx_dm,String p_cHY_Level,String p_cPX_ZD,String p_cPX_SJ)
             throws DataAccessException {
     JDBCDataSource jDBCDataSource = JDBCDataSource.getJDBCDataSource();
     PreparedStatement preparedStatement = null;
     ResultSet result = null;
     Connection conn = null;
     File tempFile = null;
     CSVWriter writer = null;
     ZipOutputStream zos = null;
     FileInputStream fis = null;
     int t1 = (int) System.currentTimeMillis();
     try {
         conn = jDBCDataSource.getConnection();
         CallableStatement proc = conn
                 .prepareCall("{call sjcq.BP_**_FHY_HS(?,?,?,?,?,?,?)}");
         proc.setString(1, p_csssq);
         proc.setString(2, p_cswjg_dm);
         proc.setString(3, p_cHymx_dm);
         proc.setString(4, p_cHY_Level);
         proc.setString(5, p_cPX_ZD);
         proc.setString(6, p_cPX_SJ);
         proc.registerOutParameter(7, OracleTypes.VARCHAR);
         proc.execute();
         String queryStr = proc.getString(7); //存储过程输出SQL语句
         preparedStatement = conn.prepareStatement(queryStr);
         result = preparedStatement.executeQuery(queryStr);

         String fileName = "农产品**查询";
         String fileExtension = ".csv";
         int bs = -1;//倍数
         int exportMax = 60000;  //一次导出6万条数据
         int temp = 1;
         String executeStr = "";
         String fullName = "";
         //FileWriter w = null;
         //if(resultCountAll/exportMax>=1){
             bs = resultCountAll/exportMax;
         //}
         while(bs>=0){
             String [] includeHeaders = {"行业代码","行业名称","户数"};  //定义导出CSV文件头文件
             if(resultCountAll>=(exportMax*temp)){  //一次导出6万条数据，多出的部分，生成第二个6万条数据文件
                 executeStr = "SELECT *  FROM (select rownum myNum,TempAA.* FROM (" + queryStr + ")TempAA ) where myNum>="
                             + (temp-1)*exportMax + " and TempAA.myNum<=" + exportMax*temp;
                 tempFile = new File(path+fileName+temp+fileExtension);
                 fullName = path+fileName+temp+fileExtension;   //指定导出的文件目录
             }else if(resultCountAll%exportMax!=0){  //剩下的不足6万条的导出最后一个文件
                 executeStr = "SELECT *  FROM (select rownum myNum,TempAA.* FROM (" + queryStr + ")TempAA ) where myNum>="
                     + (temp-1)*exportMax + " and myNum<=" + resultCountAll;
                 fullName = path+fileName+temp+fileExtension;
             }
             preparedStatement = conn.prepareStatement(executeStr);
             result = preparedStatement.executeQuery(executeStr);
             writer = new CSVWriter(new FileWriter(fullName));   //new一个CSV文件
             writer.writeNext(includeHeaders);
             while (result.next()) {
                 String[] data = new String[]{
                         StringUtil.isoToGbk(result.getString("HY_DM")),//行业代码
                          StringUtil.isoToGbk(result.getString("HY_MC")),//行业名称
                          StringUtil.isoToGbk(result.getString("HS"))//户数
                 };
                 writer.writeNext(data);
             }
             writer.flush();
             writer.close();
             if (result != null) {
                 result.close();
                 result = null;
             }
             if (preparedStatement != null) {
                 preparedStatement.close();
                 preparedStatement = null;
             }
             bs-=1;
             temp+=1;
         }
         tempFile = null;
                //如果不以压缩包的形式导出，下面的代码就完全没有必要要了。上面的部分，系统会以CSV格式导出到本地。
                 response.setContentType("application/zip");
         response.reset();
         response.setCharacterEncoding("GBK");
         response.setHeader("Content-Disposition","attachment; filename=" + new String(fileName.getBytes("GBK"),"ISO8859-1")+".zip" );
         //文件压缩
         int leng=0;
         zos = new ZipOutputStream(response.getOutputStream());
         File delFile = null;
         for(int i = temp-1;i>0;i--){
             fis = new FileInputStream(path+fileName+ i + ".csv");
             ZipEntry z1 = new ZipEntry(fileName+i+".csv");
             zos.setComment(csvExportIllustrate);
             zos.putNextEntry(z1);
             byte[] b = new byte[1024];
             while((leng = fis.read(b))!=-1){
                 zos.write(b,0,leng);
             }
             zos.setEncoding("GBK");
             fis.close();
         }
         zos.close();
         //文件删除
         for(int i = temp-1;i>0;i--){
             delFile = new File(path+fileName+ i + ".csv");
             delFile.delete();
         }
     } catch (Exception e) {
         throw new DataAccessException(e);
     } finally {
         // 释放资源
         try {
             if(zos!=null){
                 try {
                     zos.close();
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
                 zos = null;
             }
             if(fis!=null){
                 try {
                     fis.close();
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
                 fis = null;
             }

             if(writer!=null){
                 try {
                     writer.close();
                 } catch (IOException e) {
                     e.printStackTrace();
                 }
                 writer = null;
             }
             if (result != null) {
                 result.close();
                 result = null;
             }
             if (preparedStatement != null) {
                 preparedStatement.close();
                 preparedStatement = null;
             }
         } catch (SQLException e1) {
             throw new DataAccessException(e1);
         }
     }
 }

 }

以下是通用的，如果有更好的实现方法或功能，请提出建议。

 import java.io.File;
 import java.io.FileInputStream;
 import java.io.FileWriter;
 import java.io.IOException;
 import java.sql.CallableStatement;
 import java.sql.Connection;
 import java.sql.PreparedStatement;
 import java.sql.ResultSet;
 import java.sql.SQLException;
 import java.util.ArrayList;
 import java.util.List;
 import java.util.zip.ZipEntry;
 import java.util.zip.ZipOutputStream;
 import javax.servlet.http.HttpServletResponse;
 import oracle.jdbc.OracleTypes;
 import au.com.bytecode.opencsv.CSVWriter;


 public class ExportCsvToZip {
     private String zipSm = "超过6万条数据后，以CSV格式导出。";//导出zip文件说明
     /*
      * add by li_dyue
      * date: 20120324
      * function:compose csv files and export zip
      *
      *  csvFileName 暂时生成的csv文件名称
      *  exportZipName 要导出的zip文件名称
      *  includeHeaders csv文件的列表的第一列，例如：纳税人识别号、纳税人名称、税务机关等
      *  dataPO 给csv文件赋值的PO们
      *  querysql 需要查询的sql语句
      *  exportMax 定义一次最多导出多少条csv文件
      *  resultNumber 一共需要导出多少条记录
      *
      *  文件给生成到本地，查出一条就往文件里写一条，
      *  如果要把这些数据都放到内存中再压缩，那么在大数据量的时候，一定会发生内存溢出问题。
      *
      */

     public void exportZip(HttpServletResponse response, String csvFileName, String exportZipName,
             String[] includeHeaders, String[] dataPO, String querysql, int resultNumber)
             throws DataAccessException {

         JDBCDataSource jDBCDataSource = JDBCDataSource.getJDBCDataSource();
         List rs_list = new ArrayList();
         PageListData pageListData = new PageListData();
         PreparedStatement preparedStatement = null;
         ResultSet result = null;
         Connection conn = null;
         File tempFile = null;
         CSVWriter writer = null;
         ZipOutputStream zos = null;
         FileInputStream fis = null;
         //path: 先在服务器上生成csv文件的路径
         StringBuffer path = new StringBuffer();
         path.append("c:/lee/");
         String fileExtension = ".csv";
         String c = "";
         int countAll = 0;
         int bs = -1;//倍数
         int exportMax = 60000;
         int temp = 1;
         String executeStr = "";
         StringBuffer bf = new StringBuffer();
         int t1 = (int) System.currentTimeMillis();
         String[] data = new String[dataPO.length];
         try {
             conn = jDBCDataSource.getConnection();

             countAll = resultNumber;
             if(countAll/exportMax>=1){
                 bs = countAll/exportMax;
             }
             while(bs>=0){
                 if(countAll>=(exportMax*temp)){
                     executeStr = "SELECT *  FROM (select rownum myNum,TempAA.* FROM (" + querysql + ")TempAA ) where myNum>="
                                 + (temp-1)*exportMax + " and myNum<=" + exportMax*temp;
                     preparedStatement = conn.prepareStatement(executeStr);
                     result = preparedStatement.executeQuery(executeStr);
                     tempFile = new File(path+csvFileName+temp+fileExtension);
                     System.out.println("csvFileName:"+csvFileName+temp+fileExtension);
                     writer = new CSVWriter(new FileWriter(tempFile));
                     writer.writeNext(includeHeaders);

                     while (result.next()) {
                         //String[] data = new String[dataPO.length];
                                                 //!!!  此处的for循环，严重影响了导出的效率，暂无好的解决方案
                                                 for(int i=0;i<dataPO.length;i++){
                             data[i] =  StringUtil.isoToGbk(result.getString(dataPO[i]));
                         }
                         writer.writeNext(data);
                     }
                     writer.close();
                     if (result != null) {
                         result.close();
                         result = null;
                     }
                     if (preparedStatement != null) {
                         preparedStatement.close();
                         preparedStatement = null;
                     }
                 }else if(countAll%exportMax!=0){
                     executeStr = "SELECT *  FROM (select rownum myNum,aa.* FROM (" + querysql + ")aa ) where myNum>="
                     + (temp-1)*exportMax + " and myNum<=" + countAll;
                     preparedStatement = conn.prepareStatement(executeStr);
                     result = preparedStatement.executeQuery(executeStr);
                     tempFile = new File(path+csvFileName+temp+fileExtension);
                     System.out.println("csvFileName:"+csvFileName+temp+fileExtension);
                     writer = new CSVWriter(new FileWriter(tempFile));
                     writer.writeNext(includeHeaders);
                     while (result.next()) {

                         for(int i=0;i<dataPO.length;i++){
                             data[i] =  StringUtil.isoToGbk(result.getString(dataPO[i]));
                         }
                         writer.writeNext(data);
                     }
                     writer.close();
                     if (result != null) {
                         result.close();
                         result = null;
                     }
                     if (preparedStatement != null) {
                         preparedStatement.close();
                         preparedStatement = null;
                     }
                 }
                 bs-=1;
                 temp+=1;
             }
             int t2 = (int) System.currentTimeMillis();
             System.out.println((t2-t1)/3600);

             File file = new File("c:/lee/c.zip");
             String outputFile = csvFileName+temp + ".csv";

             response.setContentType("application/zip");
             response.reset();
             exportZipName = "aa";
             response.setHeader("Content-Disposition",
                     "attachment; filename=\"" + "c.zip" + "\"" );
             response.setCharacterEncoding("UTF-8");
             int leng=0;
             zos = new ZipOutputStream(response.getOutputStream());

             for(int i = temp-1;i>0;i--){
                 //System.out.println("=:"+path+csvFileName+i+fileExtension);
                 fis = new FileInputStream(path+csvFileName+i+fileExtension);
                 ZipEntry z1 = new ZipEntry(csvFileName+temp+fileExtension);
                 zos.putNextEntry(z1);
                 byte[] b = new byte[1024];
                 while((leng = fis.read(b))!=-1){
                     zos.write(b,0,leng);
                 }
             }
             zos.close();
             fis.close();

         } catch (Exception e) {
             throw new DataAccessException(e);
         } finally {
             // 释放资源
             try {
                 if(response.getOutputStream() != null)
                     response.getOutputStream().close();
             } catch (IOException e2) {
                 e2.printStackTrace();
             }
             try {
                 if(zos!=null){
                     try {
                         zos.close();
                     } catch (IOException e) {
                         e.printStackTrace();
                     }
                     zos = null;
                 }
                 if(fis!=null){
                     try {
                         fis.close();
                     } catch (IOException e) {
                         e.printStackTrace();
                     }
                     fis = null;
                 }

                 if(writer!=null){
                     try {
                         writer.close();
                     } catch (IOException e) {
                         e.printStackTrace();
                     }
                     writer = null;
                 }
                 if (result != null) {
                     result.close();
                     result = null;
                 }
                 if (preparedStatement != null) {
                     preparedStatement.close();
                     preparedStatement = null;
                 }

             } catch (SQLException e1) {
                 throw new DataAccessException(e1);
             }
         }


     }
     public void deleteCsvFiles(String path,String fileName){

     }

     //如果导出内容小于6000条，那么导出excel格式；如果导出内容大于6000条，那么导出cvs格式，然后再压缩。
     public boolean ExportToExcel(int resultCountAll){
         boolean exportExcel = false;
         if(resultCountAll<6000){
             exportExcel = true;
         }
         return exportExcel;
     }
     public String getZipSm() {
         return zipSm;
     }
     public void setZipSm(String zipSm) {
         this.zipSm = zipSm;
     }
 }