我想用Apache POI創建一個密碼保護的excel文件，然後把它下載到Servlet.getOutputStream（）

Question

我沒有權限將文件保存到文件系統。我可以在網上找到的所有例子都是使用文件系統。

我想在內存中創建如下工作簿：

HSSFWorkbook workbook = new HSSFWorkbook(); 

將數據寫入工作簿... 使工作簿密碼保護？

然後寫工作簿如下輸出流：

workbook.write(servlet.getOutputStream()); 

Answer 1

我能得到以下用的HttpServlet和HSSFWorkbook .xls文件的工作 - WorkbookServlet.java：

package com.joshden; 

import java.io.IOException; 
import java.io.OutputStream; 

import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

import org.apache.poi.hssf.record.crypto.Biff8EncryptionKey; 
import org.apache.poi.hssf.usermodel.HSSFWorkbook; 
import org.apache.poi.ss.usermodel.Workbook; 

@WebServlet("/workbook") 
public class WorkbookServlet extends HttpServlet { 
    private static final long serialVersionUID = 4087954595439224462L; 
    private static final String password = "foobar1"; 

    @Override 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException { 
     response.setContentType("application/vnd.ms-excel"); 
     response.addHeader("Content-Disposition", "attachment; filename=password_protected.xls"); 
     createAndWriteEncryptedWorkbook(response.getOutputStream()); 
    } 

    private void createAndWriteEncryptedWorkbook(OutputStream requestOutputStream) throws IOException { 
     HSSFWorkbook workbook = new HSSFWorkbook(); 
     populateWorkbook(workbook); 
     Biff8EncryptionKey.setCurrentUserPassword(password); 
     workbook.write(requestOutputStream); 
     workbook.close(); 
    } 

    private void populateWorkbook(Workbook workbook) { 
     workbook.createSheet("TestSheet"); 
     // TODO create other sheets, populate cell values 
    } 

} 

通過對/ workbook的請求，servlet使用名爲TestSheet的工作表在內存中創建HSSF工作簿。密碼設置爲「foobar1」。它會提示瀏覽器將其作爲名稱爲password_protected.xls的文件下載。

另見Apache POI - Encryption support。二進制格式（HSSF）的加密僅在Apache POI 3.16後纔可用。在寫這篇文章的時候，3.16還沒有發佈，在我的例子中我使用了3.16-beta1。

encyprtion支持指南還提供了創建加密（密碼保護）.xlsx（XSSF）文件的信息。這是我創建的一個例子，它會提示文件被命名爲password_protected.xlsx：

package com.joshden; 

import java.io.IOException; 
import java.io.OutputStream; 
import java.security.GeneralSecurityException; 

import javax.servlet.annotation.WebServlet; 
import javax.servlet.http.HttpServlet; 
import javax.servlet.http.HttpServletRequest; 
import javax.servlet.http.HttpServletResponse; 

import org.apache.poi.openxml4j.opc.OPCPackage; 
import org.apache.poi.poifs.crypt.EncryptionInfo; 
import org.apache.poi.poifs.crypt.EncryptionMode; 
import org.apache.poi.poifs.crypt.Encryptor; 
import org.apache.poi.poifs.filesystem.POIFSFileSystem; 
import org.apache.poi.ss.usermodel.Workbook; 
import org.apache.poi.xssf.usermodel.XSSFWorkbook; 

@WebServlet("/workbook") 
public class WorkbookServlet extends HttpServlet { 
    private static final long serialVersionUID = 4087954595439224462L; 
    private static final String password = "foobar1"; 

    @Override 
    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws IOException { 
     response.setContentType("application/vnd.openxmlformats-officedocument.spreadsheetml.sheet"); 
     response.addHeader("Content-Disposition", "attachment; filename=password_protected.xlsx"); 
     createAndWriteEncryptedWorkbook(response.getOutputStream()); 
    } 

    private void createAndWriteEncryptedWorkbook(OutputStream requestOutputStream) throws IOException { 
     XSSFWorkbook workbook = new XSSFWorkbook(); 
     OPCPackage opc = workbook.getPackage(); 
     populateWorkbook(workbook); 

     try { 
      POIFSFileSystem fileSystem = new POIFSFileSystem(); 
      opc.save(getEncryptingOutputStream(fileSystem, password)); 
      fileSystem.writeFilesystem(requestOutputStream); 
     } 
     finally { 
      workbook.close(); 
     } 
    } 

    private void populateWorkbook(Workbook workbook) { 
     workbook.createSheet("TestSheet"); 
     // TODO create other sheets, populate cell values 
    } 

    private OutputStream getEncryptingOutputStream(POIFSFileSystem fileSystem, String password) throws IOException { 
     EncryptionInfo encryptionInfo = new EncryptionInfo(EncryptionMode.agile); 
     Encryptor encryptor = encryptionInfo.getEncryptor(); 
     encryptor.confirmPassword(password); 

     try { 
      return encryptor.getDataStream(fileSystem); 
     } 
     catch (GeneralSecurityException e) { 
      // TODO handle this better 
      throw new RuntimeException(e); 
     } 
    } 

}