用jsp+struts2框架代码实现以下功能:导出千万级数据量,要求每50000笔数据导入到excel表格直到导完为止,再讲得到的多个excel表格压缩成zip包,最后导出为一个压缩包

以下是实现该功能的代码示例：

1. 编写Action类，实现数据导出功能

import java.io.File;
import java.io.FileInputStream;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.util.ArrayList;
import java.util.List;
import java.util.zip.ZipEntry;
import java.util.zip.ZipOutputStream;

import javax.servlet.http.HttpServletResponse;

import org.apache.poi.hssf.usermodel.HSSFWorkbook;
import org.apache.poi.ss.usermodel.CellStyle;
import org.apache.poi.ss.usermodel.Font;
import org.apache.poi.ss.usermodel.HorizontalAlignment;
import org.apache.poi.ss.usermodel.IndexedColors;
import org.apache.poi.ss.usermodel.Row;
import org.apache.poi.ss.usermodel.Sheet;
import org.apache.poi.ss.usermodel.Workbook;
import org.apache.struts2.ServletActionContext;

public class ExportAction {

    // 要导出的数据列表
    private List<Data> dataList;

    // 每次导出的数据量
    private static final int BATCH_SIZE = 50000;

    public String execute() throws Exception {
        HttpServletResponse response = ServletActionContext.getResponse();
        response.setContentType("application/zip");
        response.setHeader("Content-Disposition", "attachment; filename=data.zip");

        // 创建临时文件夹
        File tempDir = new File(System.getProperty("java.io.tmpdir"), "data");
        if (!tempDir.exists()) {
            tempDir.mkdirs();
        }

        // 按照BATCH_SIZE拆分数据，每批数据导出到一个Excel文件中
        int batchCount = (dataList.size() - 1) / BATCH_SIZE + 1;
        List<File> excelFiles = new ArrayList<File>();
        for (int i = 0; i < batchCount; i++) {
            int startIndex = i * BATCH_SIZE;
            int endIndex = Math.min(startIndex + BATCH_SIZE, dataList.size());
            List<Data> batchData = dataList.subList(startIndex, endIndex);

            File excelFile = new File(tempDir, "data-" + (i + 1) + ".xls");
            exportToExcel(batchData, excelFile);
            excelFiles.add(excelFile);
        }

        // 把多个Excel文件压缩成一个ZIP文件
        File zipFile = new File(tempDir, "data.zip");
        zipFiles(excelFiles, zipFile);

        // 输出ZIP文件
        OutputStream out = response.getOutputStream();
        FileInputStream in = new FileInputStream(zipFile);
        byte[] buffer = new byte[1024];
        int len = 0;
        while ((len = in.read(buffer)) != -1) {
            out.write(buffer, 0, len);
        }
        in.close();
        out.close();

        // 删除临时文件夹及其内容
        deleteDirectory(tempDir);

        return null;
    }

    // 把数据导出到Excel文件中
    private void exportToExcel(List<Data> data, File file) throws IOException {
        Workbook wb = new HSSFWorkbook();
        Sheet sheet = wb.createSheet("Data");

        // 设置表头样式
        CellStyle headerStyle = wb.createCellStyle();
        Font headerFont = wb.createFont();
        headerFont.setBold(true);
        headerFont.setColor(IndexedColors.WHITE.getIndex());
        headerStyle.setFillForegroundColor(IndexedColors.BLUE.getIndex());
        headerStyle.setFillPattern(CellStyle.SOLID_FOREGROUND);
        headerStyle.setAlignment(HorizontalAlignment.CENTER);
        headerStyle.setFont(headerFont);

        // 创建表头
        Row headerRow = sheet.createRow(0);
        headerRow.createCell(0).setCellValue("ID");
        headerRow.createCell(1).setCellValue("Name");
        headerRow.createCell(2).setCellValue("Age");
        headerRow.createCell(3).setCellValue("Address");
        for (int i = 0; i < headerRow.getLastCellNum(); i++) {
            headerRow.getCell(i).setCellStyle(headerStyle);
            sheet.setColumnWidth(i, 20 * 256); // 设置列宽
        }

        // 设置内容样式
        CellStyle contentStyle = wb.createCellStyle();
        Font contentFont = wb.createFont();
        contentFont.setColor(IndexedColors.BLACK.getIndex());
        contentStyle.setFont(contentFont);

        // 填充数据
        for (int i = 0; i < data.size(); i++) {
            Data d = data.get(i);
            Row row = sheet.createRow(i + 1);
            row.createCell(0).setCellValue(d.getId());
            row.createCell(1).setCellValue(d.getName());
            row.createCell(2).setCellValue(d.getAge());
            row.createCell(3).setCellValue(d.getAddress());
            for (int j = 0; j < row.getLastCellNum(); j++) {
                row.getCell(j).setCellStyle(contentStyle);
            }
        }

        // 输出Excel文件
        FileOutputStream out = new FileOutputStream(file);
        wb.write(out);
        out.close();
    }

    // 把多个文件压缩成一个ZIP文件
    private void zipFiles(List<File> files, File zipFile) throws IOException {
        byte[] buffer = new byte[1024];
        ZipOutputStream out = new ZipOutputStream(new FileOutputStream(zipFile));
        for (File file : files) {
            FileInputStream in = new FileInputStream(file);
            out.putNextEntry(new ZipEntry(file.getName()));
            int len = 0;
            while ((len = in.read(buffer)) != -1) {
                out.write(buffer, 0, len);
            }
            in.close();
        }
        out.close();
    }

    // 删除目录及其内容
    private void deleteDirectory(File dir) {
        if (dir.isDirectory()) {
            for (File file : dir.listFiles()) {
                deleteDirectory(file);
            }
        }
        dir.delete();
    }

    public List<Data> getDataList() {
        return dataList;
    }

    public void setDataList(List<Data> dataList) {
        this.dataList = dataList;
    }

}

2. JSP页面上添加导出按钮，并调用Action类的execute方法

<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%>
<%@ taglib uri="/struts-tags" prefix="s"%>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Export Data</title>
</head>
<body>
	<h1>Export Data</h1>
	<s:form action="export">
		<s:submit value="Export"/>
	</s:form>
</body>
</html>

在实际使用中，需要将数据列表传递给Action类，并在exportToExcel方法中根据实际数据结构填充Excel文件。此外，还需要在struts.xml中配置Action类的映射关系。