轉自:http://blog.csdn.net/little_stars/article/details/8266262
前文講述了 POI 讀取的基本操作,但后期 經過試驗,當寫入數據量超過5萬條以上時,
很容易報錯“內存溢出”,就算你調整JVM的xmx為 “2048MB”,也無效果。
后來查資料得知 SXSSFWorkbook 是專門用來處理大量數據寫入 Excel2007的問題的。
實例如下,具體步驟神馬的,請看前文。
讀取仍然是“XSSFWorkbook”,寫入則為“SXSSFWorkbook ”。
經試驗 寫入處理速度在 7000行左右,根據 Excel文件大小 會上下浮動。
Config.java
- package com.excel.poi.gz10000;
- import java.io.BufferedInputStream;
- import java.io.File;
- import java.io.FileInputStream;
- import java.io.FileOutputStream;
- import java.io.IOException;
- import java.io.UnsupportedEncodingException;
- import java.sql.Connection;
- import java.sql.DriverManager;
- import java.sql.ResultSet;
- import java.sql.SQLException;
- import java.sql.Statement;
- import java.text.DecimalFormat;
- import java.text.NumberFormat;
- import java.text.SimpleDateFormat;
- import java.util.ArrayList;
- import java.util.Date;
- import javax.servlet.ServletException;
- import javax.servlet.http.HttpServlet;
- import javax.servlet.http.HttpServletRequest;
- import javax.servlet.http.HttpServletResponse;
- import org.apache.log4j.Logger;
- import org.apache.log4j.PropertyConfigurator;
- import org.apache.poi.ss.usermodel.Cell;
- import org.apache.poi.ss.usermodel.Row;
- import org.apache.poi.ss.usermodel.Sheet;
- import org.apache.poi.xssf.streaming.SXSSFWorkbook;
- import org.apache.poi.xssf.usermodel.XSSFCell;
- import org.apache.poi.xssf.usermodel.XSSFWorkbook;
- /**
- * <b> 數據匹配</b> <br>
- * <ul>
- * <li> 作者:C_Dream </li>
- * <li> 當前版本:4.0 </li>
- * <li> 修改時間: 2012-12-6 17:50 </li>
- * <li> 修改內容:<ol>
- * <li> 更換Excel2007寫入方式,大幅提升性能。</li>
- * <li> 引入 log4j,局部提升性能。</li>
- * <li> 部分代碼優化,CMD輸出提示可選。</li>
- * </ol></li>
- * <li> 創建時間: 2012-11-08 19:22 </li>
- * </ul>
- */
- public class Config extends HttpServlet{
- private static final long serialVersionUID = 1L;
- //Config c = new Config();//此處決不能 new 本類,否則報錯:java.lang.StackOverflowError
- String class_path = this.getClass().getResource("").getPath();
- public void doPost(HttpServletRequest request, HttpServletResponse response)throws ServletException, IOException
- {
- this.doGet(request,response); //將 表單 post 方法傳過來的參數,轉給 get方法 去處理
- }
- public void doGet(HttpServletRequest request,HttpServletResponse response)throws ServletException, IOException
- {
- request.setCharacterEncoding("UTF-8"); //轉碼
- String forms=(String)request.getParameter("forms");
- if(forms.equals("if_3g")){
- try {
- this.read_Excel(request,response);
- } catch (SQLException e) {
- e.printStackTrace();
- } catch (ClassNotFoundException e) {
- e.printStackTrace();
- }
- }
- response.sendRedirect("index.jsp?done=true");
- }
- @SuppressWarnings("rawtypes")
- public void read_Excel(HttpServletRequest request,
- HttpServletResponse response) throws UnsupportedEncodingException, SQLException, ClassNotFoundException {
- PropertyConfigurator.configure(class_path+"log4j.properties");//獲取 log4j 配置文件
- Logger logger = Logger.getLogger(Config.class ); //獲取log4j的實例
- String startTmie = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
- logger.debug("\n**********【准備處理,正在加載文件】**********");//7
- logger.debug("\n\n**********每行數據間請不要有空行,以免程序誤判**********");//7
- logger.debug("\n\n**********由於處理Excel的插件本身性能局限,請控制文件大小,以免影響加載效率。**********");//7
- logger.debug("\n\n**********大小在\t 7 MB \t以內,大約\t 21 萬 \t行數據。**********");//7
- logger.debug("\n\n**********本程序每分鍾約處理 7000條數據,但根據文件大小會有影響。**********");//7
- request.setCharacterEncoding("UTF-8"); //轉碼
- String xls_read_Address=(String)request.getParameter("xls_read_Address");//讀取
- String xls_write_Address=(String)request.getParameter("xls_write_Address");//寫入
- String count_rows=(String)request.getParameter("count_rows");//自動編號
- String tips_cmd=(String)request.getParameter("tips_cmd");//CMD窗口的提示方式
- try {
- DataConvert dc = new DataConvert();//數據轉換工具
- DecimalFormat df = (DecimalFormat) NumberFormat.getPercentInstance();
- ArrayList<ArrayList> ls = new ArrayList<ArrayList>();
- File excel_file = new File(xls_read_Address);//讀取的文件路徑
- FileInputStream input = new FileInputStream(excel_file); //讀取的文件路徑
- XSSFWorkbook wb = new XSSFWorkbook(new BufferedInputStream(input));
- int sheet_numbers = wb.getNumberOfSheets();//獲取表的總數
- logger.debug("\n\n**********共有工作表總數**********:"+sheet_numbers);//7
- String[] sheetnames=new String[sheet_numbers];
- Connection con=null;
- Statement stmt=null;
- ResultSet rs=null;
- String s_3g=null;
- Class.forName("oracle.jdbc.driver.OracleDriver");
- con = DriverManager.getConnection("jdbc:oracle:thin:@12.12.12.123:1521:gz10000","gz12345","12345");
- stmt = con.createStatement();
- for(int i=0;i<sheet_numbers;i++){//遍歷所有表
- ArrayList<String[]> ls_a = new ArrayList<String[]>(); //用來存儲某個表 讀取出來的數據
- Sheet sheet = wb.getSheetAt(i); //獲取 某個表
- sheetnames[i] = sheet.getSheetName();//獲取表名,存入數組
- logger.debug("\n\n---正在讀取和匹配工作表\t《"+sheetnames[i]+"》\t的數據---\n");//7
- int rows_num = sheet.getLastRowNum();//獲取行數
- logger.debug("\n\n---表\t《"+sheetnames[i]+"》\t 共有數據---:\t"+rows_num+"\t行");//7
- for( int rows=0;rows<rows_num;rows++){
- Row row = sheet.getRow(rows);//取得某一行 對象
- if(row!=null&&!(row.equals(""))){
- int columns_num = row.getLastCellNum();//獲取列數
- String[] s =new String[5];//初始化數組長度
- for( int columns=0;columns<columns_num;columns++){
- Cell cell = row.getCell(columns);
- if(cell!=null){
- switch ( cell.getCellType()) {
- case XSSFCell.CELL_TYPE_STRING: // 字符串
- s[columns] = cell.getStringCellValue();
- if(s[columns]==null){
- s[columns]=" ";
- }
- break;
- case XSSFCell.CELL_TYPE_NUMERIC: // 數字
- double strCell = cell.getNumericCellValue();
- if(String.valueOf(strCell)==null){
- s[columns]=" ";
- }
- df.applyPattern("0");
- s[columns] = df.format(strCell);
- if(Double.parseDouble(s[columns])!=strCell){
- df.applyPattern(Double.toString(strCell));
- s[columns] = df.format(strCell);
- }
- break;
- case XSSFCell.CELL_TYPE_BLANK: // 空值
- s[columns]=" ";
- break;
- default:
- logger.debug("\n---單元格格式不支持---");
- break;
- }
- }
- }
- if(count_rows.equals("是")&&rows>0){
- s[0]=dc.intToString(rows);//自動編號
- }
- /* ******** 訪問數據庫 ,並判斷是否3G ******** */
- String sql="select busiattr1 from ap_t_si_cus_spec_info where cus_phone='"+s[1]+"' and rownum=1";
- rs = stmt.executeQuery(sql);
- if(rs.next()){
- if(rs.getString("busiattr1")!=null){
- s_3g = rs.getString("busiattr1").toString().toUpperCase();
- }
- else{
- s_3g=" ";
- }
- }
- else{
- s_3g=" ";
- }
- /* ******** 訪問結束 ******** */
- if(s_3g.contains("3G")){
- s[4]="是";//寫入 “是否3G”這一列 的值,比如 “是”
- }
- if(s[4]==null){
- s[4]="\t";
- }
- /* CMD窗口提示方式 */
- if(!(tips_cmd.equals("none"))&&tips_cmd!=null&&!(tips_cmd.equals(""))) {
- if(tips_cmd.equals("all")){
- logger.debug("\n匹配中:"+s[0]+"\t"+s[1]+"\t"+s[2]+"\t"+s[3]+"\t"+ s[4]);
- }else
- if(rows%DataConvert.stringToInt(tips_cmd)==0){
- logger.debug("\n匹配中:"+s[0]+"\t"+s[1]+"\t"+s[2]+"\t"+s[3]+"\t"+ s[4]);
- }
- }
- ls_a.add(s);//添加每行數據到 ls_a
- }
- }
- ls.add(ls_a); //添加 每個表 到 ls
- input.close();
- write_Excel( xls_write_Address, ls, sheetnames ,tips_cmd) ;
- }
- } catch (IOException ex) {
- ex.printStackTrace();
- }
- String endTmie = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss").format(new Date());
- logger.debug("\n\n***************【處理完成,程序結束】***************");//7
- logger.debug("\n開始時間:"+startTmie);
- logger.debug("\n結束時間:"+endTmie);
- logger.debug("\n新文件輸出路徑為:"+xls_write_Address);
- }
- @SuppressWarnings({ "rawtypes", "unchecked" })
- public void write_Excel( String xls_write_Address,ArrayList<ArrayList> ls,String[] sheetnames,String tips_cmd ) throws IOException {
- PropertyConfigurator.configure(class_path+"log4j.properties");//獲取 log4j 配置文件
- Logger logger = Logger.getLogger(Config.class ); //獲取log4j的實例
- FileOutputStream output = new FileOutputStream(new File(xls_write_Address)); //讀取的文件路徑
- SXSSFWorkbook wb = new SXSSFWorkbook(10000);//內存中保留 10000 條數據,以免內存溢出,其余寫入 硬盤
- for(int sn=0;sn<ls.size();sn++){
- Sheet sheet = wb.createSheet(String.valueOf(sn));
- wb.setSheetName(sn, sheetnames[sn]);
- ArrayList<String[]> ls2 = ls.get(sn);
- for(int i=0;i<ls2.size();i++){
- Row row = sheet.createRow(i);
- String[] s = ls2.get(i);
- for(int cols=0;cols<s.length;cols++){
- Cell cell = row.createCell(cols);
- cell.setCellType(XSSFCell.CELL_TYPE_STRING);//文本格式
- sheet.setColumnWidth(cols, s[cols].length()*384); //設置單元格寬度
- cell.setCellValue(s[cols]);//寫入內容
- }
- /* CMD窗口提示方式 */
- if(!(tips_cmd.equals("none"))&&tips_cmd!=null&&!(tips_cmd.equals(""))) {
- if(tips_cmd.equals("all")){
- logger.debug("\n寫入中:"+s[0]+"\t"+s[1]+"\t"+s[2]+"\t"+s[3]+"\t"+ s[4]);
- }else
- if(i%DataConvert.stringToInt(tips_cmd)==0){
- logger.debug("\n寫入中:"+s[0]+"\t"+s[1]+"\t"+s[2]+"\t"+s[3]+"\t"+ s[4]);
- }
- }
- }
- }
- wb.write(output);
- output.close();
- }
- }