java导出excel（解决导出几万条数据内存溢出的问题）

import java.io.BufferedOutputStream;

import java.io.DataOutputStream;

import java.io.File;

import java.io.FileNotFoundException;

import java.io.FileOutputStream;

import java.io.IOException;



public class Test {  

    public static void main(String[] args) {  

    	System.out.println(System.currentTimeMillis());

        StringBuffer sb = new StringBuffer();  

        try {  

            DataOutputStream rafs = new DataOutputStream(  

                    new BufferedOutputStream(new FileOutputStream(new File(  

                            "d://test.xlsx"))));  

            sb.append("<?xml version=\"1.0\"?>");  

            sb.append("\n");  

            sb.append("<?mso-application progid=\"Excel.Sheet\"?>");  

            sb.append("\n");  

            sb.append("<Workbook xmlns=\"urn:schemas-microsoft-com:office:spreadsheet\"");  

            sb.append("\n");  

            sb.append("  xmlns:o=\"urn:schemas-microsoft-com:office:office\"");  

            sb.append("\n");  

            sb.append(" xmlns:x=\"urn:schemas-microsoft-com:office:excel\"");  

            sb.append("\n");  

            sb.append(" xmlns:ss=\"urn:schemas-microsoft-com:office:spreadsheet\"");  

            sb.append("\n");  

            sb.append(" xmlns:html=\"http://www.w3.org/TR/REC-html40\">");  

            sb.append("\n");  

            sb.append(" <Styles>\n");  

            sb.append("  <Style ss:ID=\"Default\" ss:Name=\"Normal\">\n");  

            sb.append("   <Alignment ss:Vertical=\"Center\"/>\n");  

            sb.append("   <Borders/>\n");  

            sb.append("   <Font ss:FontName=\"宋体\" x:CharSet=\"134\" ss:Size=\"12\"/>\n");  

            sb.append("   <Interior/>\n");  

            sb.append("   <NumberFormat/>\n");  

            sb.append("   <Protection/>\n");  

            sb.append("  </Style>\n");  

            sb.append(" </Styles>\n");  

//             int sheetcount = 0;  

            int recordcount = 100000;  

            int currentRecord = 0;  

            int total = 100000;  

            int col = 10;  

            sb.append("<Worksheet ss:Name=\"Sheet0\">");  

            sb.append("\n");  

            sb.append("<Table ss:ExpandedColumnCount=\"" + col  

                    + "\" ss:ExpandedRowCount=\"" + total  

                    + "\" x:FullColumns=\"1\" x:FullRows=\"1\">");  

            sb.append("\n");  

            for (int i = 0; i < total; i++) {  

                if ((currentRecord == recordcount  

                        || currentRecord > recordcount || currentRecord == 0)  

                        && i != 0) {// 一个sheet写满  

                    currentRecord = 0;  

                    rafs.write(sb.toString().getBytes());  

                    sb.setLength(0);  

                    sb.append("</Table>");  

                    sb.append("<WorksheetOptions xmlns=\"urn:schemas-microsoft-com:office:excel\">");  

                    sb.append("\n");  

                    sb.append("<ProtectObjects>False</ProtectObjects>");  

                    sb.append("\n");  

                    sb.append("<ProtectScenarios>False</ProtectScenarios>");  

                    sb.append("\n");  

                    sb.append("</WorksheetOptions>");  

                    sb.append("\n");  

                    sb.append("</Worksheet>");  

                    sb.append("<Worksheet ss:Name=\"Sheet" + i / recordcount  

                            + "\">");  

                    sb.append("\n");  

                    sb.append("<Table ss:ExpandedColumnCount=\"" + col  

                            + "\" ss:ExpandedRowCount=\"" + recordcount  

                            + "\" x:FullColumns=\"1\" x:FullRows=\"1\">");  

                    sb.append("\n");  

                }  

                sb.append("<Row>");  

                for (int j = 0; j < col; j++) {  

                	if(i==0) sb.append("<Cell><Data ss:Type=\"String\">标题"+j+"</Data></Cell>"); 

                	else sb.append("<Cell><Data ss:Type=\"String\">c"+i+"&"+j+"</Data></Cell>"); 

                    

                    sb.append("\n");  

                }  

                sb.append("</Row>");  

                if (i % 5000 == 0) {  

                    rafs.write(sb.toString().getBytes("utf-8"));  //注意编码

                    rafs.flush();  

                    sb.setLength(0);  

                }  

                sb.append("\n");  

                currentRecord++;  

            }  

            rafs.write(sb.toString().getBytes());  

            sb.setLength(0);  

            sb.append("</Table>");  

            sb.append("<WorksheetOptions xmlns=\"urn:schemas-microsoft-com:office:excel\">");  

            sb.append("\n");  

            sb.append("<ProtectObjects>False</ProtectObjects>");  

            sb.append("\n");  

            sb.append("<ProtectScenarios>False</ProtectScenarios>");  

            sb.append("\n");  

            sb.append("</WorksheetOptions>");  

            sb.append("\n");  

            sb.append("</Worksheet>");  

            sb.append("</Workbook>");  

            sb.append("\n");  

            rafs.write(sb.toString().getBytes());  

            rafs.flush();  

            rafs.close();  

            System.out.println(System.currentTimeMillis());

        } catch (FileNotFoundException e) {  

            e.printStackTrace();  

        } catch (IOException e) {  

            e.printStackTrace();  

        }  

    }  

}