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("
");  
            sb.append("<?mso-application progid="Excel.Sheet"?>");  
            sb.append("
");  
            sb.append("<Workbook xmlns="urn:schemas-microsoft-com:office:spreadsheet"");  
            sb.append("
");  
            sb.append("  xmlns:o="urn:schemas-microsoft-com:office:office"");  
            sb.append("
");  
            sb.append(" xmlns:x="urn:schemas-microsoft-com:office:excel"");  
            sb.append("
");  
            sb.append(" xmlns:ss="urn:schemas-microsoft-com:office:spreadsheet"");  
            sb.append("
");  
            sb.append(" xmlns:html="http://www.w3.org/TR/REC-html40">");  
            sb.append("
");  
            sb.append(" <Styles>
");  
            sb.append("  <Style ss:ID="Default" ss:Name="Normal">
");  
            sb.append("   <Alignment ss:Vertical="Center"/>
");  
            sb.append("   <Borders/>
");  
            sb.append("   <Font ss:FontName="宋体" x:CharSet="134" ss:Size="12"/>
");  
            sb.append("   <Interior/>
");  
            sb.append("   <NumberFormat/>
");  
            sb.append("   <Protection/>
");  
            sb.append("  </Style>
");  
            sb.append(" </Styles>
");  
//             int sheetcount = 0;  
            int recordcount = 100000;  
            int currentRecord = 0;  
            int total = 100000;  
            int col = 10;  
            sb.append("<Worksheet ss:Name="Sheet0">");  
            sb.append("
");  
            sb.append("<Table ss:ExpandedColumnCount="" + col  
                    + "" ss:ExpandedRowCount="" + total  
                    + "" x:FullColumns="1" x:FullRows="1">");  
            sb.append("
");  
            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("
");  
                    sb.append("<ProtectObjects>False</ProtectObjects>");  
                    sb.append("
");  
                    sb.append("<ProtectScenarios>False</ProtectScenarios>");  
                    sb.append("
");  
                    sb.append("</WorksheetOptions>");  
                    sb.append("
");  
                    sb.append("</Worksheet>");  
                    sb.append("<Worksheet ss:Name="Sheet" + i / recordcount  
                            + "">");  
                    sb.append("
");  
                    sb.append("<Table ss:ExpandedColumnCount="" + col  
                            + "" ss:ExpandedRowCount="" + recordcount  
                            + "" x:FullColumns="1" x:FullRows="1">");  
                    sb.append("
");  
                }  
                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("
");  
                }  
                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("
");  
                currentRecord++;  
            }  
            rafs.write(sb.toString().getBytes());  
            sb.setLength(0);  
            sb.append("</Table>");  
            sb.append("<WorksheetOptions xmlns="urn:schemas-microsoft-com:office:excel">");  
            sb.append("
");  
            sb.append("<ProtectObjects>False</ProtectObjects>");  
            sb.append("
");  
            sb.append("<ProtectScenarios>False</ProtectScenarios>");  
            sb.append("
");  
            sb.append("</WorksheetOptions>");  
            sb.append("
");  
            sb.append("</Worksheet>");  
            sb.append("</Workbook>");  
            sb.append("
");  
            rafs.write(sb.toString().getBytes());  
            rafs.flush();  
            rafs.close();  
            System.out.println(System.currentTimeMillis());
        } catch (FileNotFoundException e) {  
            e.printStackTrace();  
        } catch (IOException e) {  
            e.printStackTrace();  
        }  
    }  
}