使用POI将大型结果集写入Excel文件

This is sort of inline w/ Writing a large ResultSet to a File but the file in question is an Excel file.

这是一种内联w /将大型ResultSet写入文件但有问题的文件是Excel文件。

I'm using the Apache POI library to write an Excel file with a large data set retrieved from a ResultSet object. The data could range from a few thousand records to about 1 million; not sure how this translates into file system bytes in Excel format.

我正在使用Apache POI库编写一个Excel文件,其中包含从ResultSet对象检索到的大型数据集。数据范围从几千条记录到大约一百万条;不确定这如何转换为Excel格式的文件系统字节。

The following is a test code I wrote to check out the time taken to write such a large result set and also the performance implication w.r.t CPU & Memory.

以下是我编写的测试代码,用于检查编写如此大的结果集所花费的时间以及w.r.t CPU和内存的性能影响。

protected void writeResultsetToExcelFile(ResultSet rs, int numSheets, String fileNameAndPath) throws Exception {

    BufferedOutputStream bos = new BufferedOutputStream(new FileOutputStream(fileNameAndPath));
    int numColumns = rs.getMetaData().getColumnCount();

    Workbook wb = ExcelFileUtil.createExcelWorkBook(true, numSheets);
    Row heading = wb.getSheetAt(0).createRow(1);

    ResultSetMetaData rsmd = rs.getMetaData();

    for(int x = 0; x < numColumns; x++) {
        Cell cell = heading.createCell(x+1);
        cell.setCellValue(rsmd.getColumnLabel(x+1));
    }

    int rowNumber = 2;
    int sheetNumber = 0;

    while(rs.next()) {

        if(rowNumber == 65001) {
            log("Sheet " + sheetNumber + "written; moving onto to sheet " + (sheetNumber + 1));
            sheetNumber++;
            rowNumber = 2;
        }

        Row row = wb.getSheetAt(sheetNumber).createRow(rowNumber);
        for(int y = 0; y < numColumns; y++) {
            row.createCell(y+1).setCellValue(rs.getString(y+1));
            wb.write(bos);
        }

        rowNumber++;
    }

    //wb.write(bos);

    bos.close();
}

Not much luck with the above code. The file which is created seems to grow rapidly (~70Mb per sec). So I stopped the execution after about 10 minutes (killed the JVM when the file reaches 7Gb) and tried to open the file in Excel 2007. The moment I open it, the file size becomes 8k(!) and only the header and the first row are created. Not sure what I'm missing here.

上面的代码没多少运气。创建的文件似乎快速增长(每秒约70Mb)。所以我在大约10分钟后停止执行(当文件达到7Gb时杀死JVM)并尝试在Excel 2007中打开文件。当我打开它时,文件大小变为8k(!)并且只有标题和第一个行已创建。不知道我在这里缺少什么。

Any ideas?

6 个解决方案

#1

Oh. I think you're writing the workbook out 944,000 times. Your wb.write(bos) call is in the inner loop. I'm not sure this is quite consistent with the semantics of the Workbook class? From what I can tell in the Javadocs of that class, that method writes out the entire workbook to the output stream specified. And it's gonna write out every row you've added so far once for every row as the thing grows.

哦。我认为你正在编写工作簿944,000次。你的wb.write(bos)调用是在内部循环中。我不确定这与Workbook类的语义是否完全一致?从我在该类的Javadocs中可以看出,该方法将整个工作簿写出到指定的输出流。随着事情的发展,它会写出你目前为每一行添加的每一行。

This explains why you're seeing exactly 1 row, too. The first workbook (with one row) to be written out to the file is all that is being displayed - and then 7GB of junk thereafter.

这就解释了为什么你也看到了正好一行。将要写入文件的第一个工作簿(有一行)显示所有内容 - 然后是7GB的垃圾。

#2

Using SXSSF poi 3.8

使用SXSSF poi 3.8

package example;

import java.io.FileInputStream;
import java.io.FileOutputStream;

import org.apache.poi.ss.usermodel.Cell;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.util.CellReference;
import org.apache.poi.xssf.streaming.SXSSFSheet;
import org.apache.poi.xssf.streaming.SXSSFWorkbook;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

public class SXSSFexample {


    public static void main(String[] args) throws Throwable {
        FileInputStream inputStream = new FileInputStream("mytemplate.xlsx");
        XSSFWorkbook wb_template = new XSSFWorkbook(inputStream);
        inputStream.close();

        SXSSFWorkbook wb = new SXSSFWorkbook(wb_template); 
        wb.setCompressTempFiles(true);

        SXSSFSheet sh = (SXSSFSheet) wb.getSheetAt(0);
        sh.setRandomAccessWindowSize(100);// keep 100 rows in memory, exceeding rows will be flushed to disk
    for(int rownum = 4; rownum < 100000; rownum++){
        Row row = sh.createRow(rownum);
        for(int cellnum = 0; cellnum < 10; cellnum++){
            Cell cell = row.createCell(cellnum);
            String address = new CellReference(cell).formatAsString();
            cell.setCellValue(address);
        }

    }


    FileOutputStream out = new FileOutputStream("tempsxssf.xlsx");
    wb.write(out);
    out.close();
}

}

It requires:

• poi-ooxml-3.8.jar,
• poi-3.8.jar,
• poi-ooxml-schemas-3.8.jar,
• stax-api-1.0.1.jar,
• xml-apis-1.0.b2.jar,
• xmlbeans-2.3.0.jar,
• commons-codec-1.5.jar,
• dom4j-1.6.1.jar

Useful link

#3

Unless you have to write formulas or formatting you should consider writing out a .csv file. Infinitely simpler, infinitely faster, and Excel will do the conversion to .xls or .xlsx automatically and correctly by definition.

除非您必须编写公式或格式,否则应考虑写出.csv文件。无限简单,无限快,Excel将根据定义自动和正确地转换为.xls或.xlsx。

#4

You can using SXSSFWorkbook implementation of Workbook, if you use style in your excel ,You can caching style by Flyweight Pattern to improve your performance.

您可以使用SXSSFWorkbook实现Workbook,如果您在excel中使用样式,您可以通过Flyweight Pattern缓存样式以提高您的性能。

#5

For now I took @Gian's advice & limited the number of records per Workbook to 500k and rolled over the rest to the next Workbook. Seems to be working decent. For the above configuration, it took me about 10 mins per workbook.

现在我接受了@Gian的建议并将每个工作簿的记录数量限制在500k,并将其余部分翻到下一个工作簿。似乎工作得体。对于上面的配置,每个工作簿花了大约10分钟。

#6

I updated BigGridDemo to support multiple sheets.

我更新了BigGridDemo以支持多张表格。

BigExcelWriterImpl.java

package com.gdais.common.apache.poi.bigexcelwriter;

import static com.google.common.base.Preconditions.*;

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.InputStream;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.io.Writer;
import java.util.Enumeration;
import java.util.HashMap;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.zip.ZipEntry;
import java.util.zip.ZipFile;
import java.util.zip.ZipOutputStream;

import javax.annotation.Nonnull;
import javax.annotation.Nullable;

import org.apache.commons.io.FilenameUtils;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.poi.xssf.usermodel.XSSFSheet;
import org.apache.poi.xssf.usermodel.XSSFWorkbook;

import com.google.common.base.Function;
import com.google.common.collect.ImmutableList;
import com.google.common.collect.Iterables;

public class BigExcelWriterImpl implements BigExcelWriter {

private static final String XML_ENCODING = "UTF-8";

@Nonnull
private final File outputFile;

@Nullable
private final File tempFileOutputDir;

@Nullable
private File templateFile = null;

@Nullable
private XSSFWorkbook workbook = null;

@Nonnull
private LinkedHashMap<String, XSSFSheet> addedSheets = new LinkedHashMap<String, XSSFSheet>();

@Nonnull
private Map<XSSFSheet, File> sheetTempFiles = new HashMap<XSSFSheet, File>();

BigExcelWriterImpl(@Nonnull File outputFile) {
    this.outputFile = outputFile;
    this.tempFileOutputDir = outputFile.getParentFile();
}

@Override
public BigExcelWriter createWorkbook() {
    workbook = new XSSFWorkbook();
    return this;
}

@Override
public BigExcelWriter addSheets(String... sheetNames) {
    checkState(workbook != null, "workbook must be created before adding sheets");

    for (String sheetName : sheetNames) {
        XSSFSheet sheet = workbook.createSheet(sheetName);
        addedSheets.put(sheetName, sheet);
    }

    return this;
}

@Override
public BigExcelWriter writeWorkbookTemplate() throws IOException {
    checkState(workbook != null, "workbook must be created before writing template");
    checkState(templateFile == null, "template file already written");

    templateFile = File.createTempFile(FilenameUtils.removeExtension(outputFile.getName())
            + "-template", ".xlsx", tempFileOutputDir);
    System.out.println(templateFile);
    FileOutputStream os = new FileOutputStream(templateFile);
    workbook.write(os);
    os.close();

    return this;
}

@Override
public SpreadsheetWriter createSpreadsheetWriter(String sheetName) throws IOException {
    if (!addedSheets.containsKey(sheetName)) {
        addSheets(sheetName);
    }

    return createSpreadsheetWriter(addedSheets.get(sheetName));
}

@Override
public SpreadsheetWriter createSpreadsheetWriter(XSSFSheet sheet) throws IOException {
    checkState(!sheetTempFiles.containsKey(sheet), "writer already created for this sheet");

    File tempSheetFile = File.createTempFile(
            FilenameUtils.removeExtension(outputFile.getName())
                    + "-sheet" + sheet.getSheetName(), ".xml", tempFileOutputDir);

    Writer out = null;
    try {
        out = new OutputStreamWriter(new FileOutputStream(tempSheetFile), XML_ENCODING);
        SpreadsheetWriter sw = new SpreadsheetWriterImpl(out);

        sheetTempFiles.put(sheet, tempSheetFile);
        return sw;
    } catch (RuntimeException e) {
        if (out != null) {
            out.close();
        }
        throw e;
    }
}

private static Function<XSSFSheet, String> getSheetName = new Function<XSSFSheet, String>() {

    @Override
    public String apply(XSSFSheet sheet) {
        return sheet.getPackagePart().getPartName().getName().substring(1);
    }
};

@Override
public File completeWorkbook() throws IOException {
    FileOutputStream out = null;
    try {
        out = new FileOutputStream(outputFile);
        ZipOutputStream zos = new ZipOutputStream(out);

        Iterable<String> sheetEntries = Iterables.transform(sheetTempFiles.keySet(),
                getSheetName);
        System.out.println("Sheet Entries: " + sheetEntries);
        copyTemplateMinusEntries(templateFile, zos, sheetEntries);

        for (Map.Entry<XSSFSheet, File> entry : sheetTempFiles.entrySet()) {
            XSSFSheet sheet = entry.getKey();
            substituteSheet(entry.getValue(), getSheetName.apply(sheet), zos);
        }
        zos.close();
        out.close();

        return outputFile;
    } finally {
        if (out != null) {
            out.close();
        }
    }
}

private static void copyTemplateMinusEntries(File templateFile,
        ZipOutputStream zos, Iterable<String> entries) throws IOException {

    ZipFile templateZip = new ZipFile(templateFile);

    @SuppressWarnings("unchecked")
    Enumeration<ZipEntry> en = (Enumeration<ZipEntry>) templateZip.entries();
    while (en.hasMoreElements()) {
        ZipEntry ze = en.nextElement();
        if (!Iterables.contains(entries, ze.getName())) {
            System.out.println("Adding template entry: " + ze.getName());
            zos.putNextEntry(new ZipEntry(ze.getName()));
            InputStream is = templateZip.getInputStream(ze);
            copyStream(is, zos);
            is.close();
        }
    }
}

private static void substituteSheet(File tmpfile, String entry,
        ZipOutputStream zos)
        throws IOException {
    System.out.println("Adding sheet entry: " + entry);
    zos.putNextEntry(new ZipEntry(entry));
    InputStream is = new FileInputStream(tmpfile);
    copyStream(is, zos);
    is.close();
}

private static void copyStream(InputStream in, OutputStream out) throws IOException {
    byte[] chunk = new byte[1024];
    int count;
    while ((count = in.read(chunk)) >= 0) {
        out.write(chunk, 0, count);
    }
}

@Override
public Workbook getWorkbook() {
    return workbook;
}

@Override
public ImmutableList<XSSFSheet> getSheets() {
    return ImmutableList.copyOf(addedSheets.values());
}

}

SpreadsheetWriterImpl.java

package com.gdais.common.apache.poi.bigexcelwriter;

import java.io.IOException;
import java.io.Writer;
import java.util.Calendar;

import org.apache.poi.ss.usermodel.DateUtil;
import org.apache.poi.ss.util.CellReference;

class SpreadsheetWriterImpl implements SpreadsheetWriter {

private static final String XML_ENCODING = "UTF-8";

private final Writer _out;
private int _rownum;

SpreadsheetWriterImpl(Writer out) {
    _out = out;
}

@Override
public SpreadsheetWriter closeFile() throws IOException {
    _out.close();

    return this;
}

@Override
public SpreadsheetWriter beginSheet() throws IOException {
    _out.write("<?xml version=\"1.0\" encoding=\""
            + XML_ENCODING
            + "\"?>"
            +
            "<worksheet xmlns=\"http://schemas.openxmlformats.org/spreadsheetml/2006/main\">");
    _out.write("<sheetData>\n");

    return this;
}

@Override
public SpreadsheetWriter endSheet() throws IOException {
    _out.write("</sheetData>");
    _out.write("</worksheet>");

    closeFile();
    return this;
}

/**
 * Insert a new row
 * 
 * @param rownum
 *            0-based row number
 */
@Override
public SpreadsheetWriter insertRow(int rownum) throws IOException {
    _out.write("<row r=\"" + (rownum + 1) + "\">\n");
    this._rownum = rownum;

    return this;
}

/**
 * Insert row end marker
 */
@Override
public SpreadsheetWriter endRow() throws IOException {
    _out.write("</row>\n");

    return this;
}

@Override
public SpreadsheetWriter createCell(int columnIndex, String value, int styleIndex)
        throws IOException {
    String ref = new CellReference(_rownum, columnIndex).formatAsString();
    _out.write("<c r=\"" + ref + "\" t=\"inlineStr\"");
    if (styleIndex != -1) {
        _out.write(" s=\"" + styleIndex + "\"");
    }
    _out.write(">");
    _out.write("<is><t>" + value + "</t></is>");
    _out.write("</c>");

    return this;
}

@Override
public SpreadsheetWriter createCell(int columnIndex, String value) throws IOException {
    createCell(columnIndex, value, -1);

    return this;
}

@Override
public SpreadsheetWriter createCell(int columnIndex, double value, int styleIndex)
        throws IOException {
    String ref = new CellReference(_rownum, columnIndex).formatAsString();
    _out.write("<c r=\"" + ref + "\" t=\"n\"");
    if (styleIndex != -1) {
        _out.write(" s=\"" + styleIndex + "\"");
    }
    _out.write(">");
    _out.write("<v>" + value + "</v>");
    _out.write("</c>");

    return this;
}

@Override
public SpreadsheetWriter createCell(int columnIndex, double value) throws IOException {
    createCell(columnIndex, value, -1);

    return this;
}

@Override
public SpreadsheetWriter createCell(int columnIndex, Calendar value, int styleIndex)
        throws IOException {
    createCell(columnIndex, DateUtil.getExcelDate(value, false), styleIndex);

    return this;
}

@Override
public SpreadsheetWriter createCell(int columnIndex, Calendar value)
        throws IOException {
    createCell(columnIndex, value, -1);

    return this;
}
}