WildFly与PrimeFaces文件上传定制：加密临时文件

针对Undertow原生Multipart解析和PrimeFaces+Commons FileUpload两种场景，分别提供临时文件加密的实现方案：

一、Undertow原生Multipart上传加密 #

Undertow通过MultiPartUploadHandler创建上传临时文件，可通过自定义FileFactory替换默认的临时文件创建逻辑，实现加密写入。

1. 自定义加密版FileFactory #

实现Undertow的FileFactory接口，在创建临时文件输出流时，用加密流包装：

import io.undertow.server.handlers.form.FileFactory;
import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.File;
import java.io.FileOutputStream;
import java.io.IOException;
import java.io.OutputStream;
import java.nio.file.Files;
import java.security.SecureRandom;

public class EncryptedTempFileFactory implements FileFactory {
    // 建议从安全配置源读取密钥，而非硬编码
    private final byte[] encryptionKey = System.getenv("UPLOAD_ENCRYPT_KEY").getBytes();
    private final String cipherAlgorithm = "AES/CBC/PKCS5Padding";

    @Override
    public OutputStream createFile(File file) throws IOException {
        Files.createFile(file.toPath());
        FileOutputStream fos = new FileOutputStream(file);

        try {
            // 生成随机IV（AES-IV固定16字节）
            SecureRandom secureRandom = new SecureRandom();
            byte[] iv = new byte[16];
            secureRandom.nextBytes(iv);
            // 将IV写入文件开头，解密时需先读取
            fos.write(iv);

            // 初始化加密Cipher
            SecretKeySpec keySpec = new SecretKeySpec(encryptionKey, "AES");
            Cipher cipher = Cipher.getInstance(cipherAlgorithm);
            cipher.init(Cipher.ENCRYPT_MODE, keySpec, new IvParameterSpec(iv));

            return new CipherOutputStream(fos, cipher);
        } catch (Exception e) {
            fos.close();
            Files.deleteIfExists(file.toPath());
            throw new IOException("Failed to initialize encrypted stream", e);
        }
    }

    @Override
    public File createTempFile(String prefix, String suffix, File directory) throws IOException {
        // 复用默认临时文件路径生成逻辑
        return File.createTempFile(prefix, suffix, directory);
    }
}

2. 配置Undertow使用自定义FileFactory #

编程式配置（嵌入式/自定义部署）

在Undertow部署配置中替换默认的Multipart工厂：

import io.undertow.servlet.api.DeploymentInfo;
import io.undertow.servlet.api.MultiPartConfigFactory;

// 构建部署信息时配置
DeploymentInfo deploymentInfo = new DeploymentInfo()
        .setContextPath("/your-app")
        .setDeploymentName("your-app.war")
        // 其他Servlet/过滤器配置...
        .setMultipartConfigFactory(new MultiPartConfigFactory()
                .setFileFactory(new EncryptedTempFileFactory()));

WildFly容器配置

若使用WildFly standalone服务器，需将自定义类打包为WildFly模块，在jboss-deployment-structure.xml中声明依赖，再通过CDI扩展或自定义Undertow Servlet容器配置替换FileFactory。

二、PrimeFaces + Commons FileUpload加密 #

PrimeFaces使用Commons FileUpload时，临时文件由DiskFileItemFactory创建，可通过继承该类并重写文件项创建逻辑实现加密。

1. 自定义加密版DiskFileItemFactory #

import org.apache.commons.fileupload.disk.DiskFileItem;
import org.apache.commons.fileupload.disk.DiskFileItemFactory;
import org.apache.commons.fileupload.FileItem;
import javax.crypto.Cipher;
import javax.crypto.CipherOutputStream;
import javax.crypto.spec.IvParameterSpec;
import javax.crypto.spec.SecretKeySpec;
import java.io.FileOutputStream;
import java.io.IOException;
import java.security.SecureRandom;

public class EncryptedDiskFileItemFactory extends DiskFileItemFactory {
    private final byte[] encryptionKey = System.getenv("UPLOAD_ENCRYPT_KEY").getBytes();
    private final String cipherAlgorithm = "AES/CBC/PKCS5Padding";

    @Override
    public FileItem createItem(String fieldName, String contentType, boolean isFormField, String fileName) {
        DiskFileItem item = (DiskFileItem) super.createItem(fieldName, contentType, isFormField, fileName);

        try {
            FileOutputStream fos = new FileOutputStream(item.getStoreLocation());
            // 生成随机IV并写入文件开头
            SecureRandom secureRandom = new SecureRandom();
            byte[] iv = new byte[16];
            secureRandom.nextBytes(iv);
            fos.write(iv);

            // 初始化加密Cipher
            SecretKeySpec keySpec = new SecretKeySpec(encryptionKey, "AES");
            Cipher cipher = Cipher.getInstance(cipherAlgorithm);
            cipher.init(Cipher.ENCRYPT_MODE, keySpec, new IvParameterSpec(iv));

            // 替换文件项的输出流为加密流
            item.setOutputStream(new CipherOutputStream(fos, cipher));
        } catch (Exception e) {
            item.delete();
            throw new RuntimeException("Failed to create encrypted temp file", e);
        }

        return item;
    }
}

2. 配置PrimeFaces使用自定义工厂 #

在faces-config.xml中配置FileUpload过滤器，指定自定义工厂类：

<filter>
    <filter-name>PrimeFaces FileUpload Filter</filter-name>
    <filter-class>org.primefaces.webapp.filter.FileUploadFilter</filter-class>
    <init-param>
        <param-name>uploader</param-name>
        <param-value>commons</param-value>
    </init-param>
    <init-param>
        <param-name>factory</param-name>
        <param-value>com.your.package.EncryptedDiskFileItemFactory</param-value>
    </init-param>
</filter>

关键注意事项 #

• 密钥管理：绝对禁止硬编码密钥，应使用WildFly安全Vault、环境变量或密钥管理服务（KMS）存储和读取密钥。
• 解密逻辑：读取加密临时文件时，需先读取文件开头的IV，再初始化Cipher.DECRYPT_MODE，用CipherInputStream读取内容。
• 性能考量：加密会增加CPU开销，需根据业务并发量测试性能，必要时调整加密算法或优化IO逻辑。
• 临时文件清理：确保加密临时文件在使用后正常删除，避免磁盘空间泄漏。

内容的提问来源于stack exchange，提问作者László Tóth