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java导出excel(解决导出几万条数据内存溢出的问题)

2014-06-17 14:54 721 查看
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();
}
}
}


  
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