Java 개발의 일반적인 보안 취약점 및 솔루션

String sql = "SELECT * FROM users WHERE username = ?";
PreparedStatement statement = connection.prepareStatement(sql);
statement.setString(1, userInput);
ResultSet resultSet = statement.executeQuery();

String userInput = "<script>alert('XSS attack');</script>";
String safeInput = StringEscapeUtils.escapeHtml4(userInput);
System.out.println(safeInput);

// 在用户登录时生成CSRF令牌，并存储在Session中
String csrfToken = generateCSRFToken();
session.setAttribute("csrfToken", csrfToken);

// 在提交表单时验证CSRF令牌的有效性
String userToken = request.getParameter("csrfToken");
String serverToken = session.getAttribute("csrfToken");
if (serverToken.equals(userToken)) {
    // 验证通过，执行敏感操作
    // ...
} else {
    // 验证失败，拒绝请求或采取其他安全措施
}

// 生成RSA密钥对
KeyPairGenerator keyPairGenerator = KeyPairGenerator.getInstance("RSA");
keyPairGenerator.initialize(2048);
KeyPair keyPair = keyPairGenerator.generateKeyPair();

// 对明文进行加密
Cipher cipher = Cipher.getInstance("RSA");
cipher.init(Cipher.ENCRYPT_MODE, keyPair.getPublic());
byte[] encryptedData = cipher.doFinal(plainText.getBytes());

// 对密文进行解密
cipher.init(Cipher.DECRYPT_MODE, keyPair.getPrivate());
byte[] decryptedData = cipher.doFinal(encryptedData);

// 对数据进行数字签名
Signature signature = Signature.getInstance("SHA256withRSA");
signature.initSign(keyPair.getPrivate());
signature.update(data);
byte[] signatureData = signature.sign();

// 验证数字签名的合法性
Signature signature = Signature.getInstance("SHA256withRSA");
signature.initVerify(keyPair.getPublic());
signature.update(data);
boolean isValid = signature.verify(signatureData);