Fortofy扫描安全漏洞解决——Unreleased Resource: Streams未释放资源漏洞

问题描述：
大部分 Unreleased Resource 问题只会导致一般的软件可靠性问题，但如果攻击者能够故意触发资源泄漏，该攻击者就有可能通过耗尽资源池的方式发起 denial of service 攻击。

问题代码：

 FileInputStream inputStream = new FileInputStream(sourcePath);
 FileOutputStream outputStream = new FileOutputStream(destinationPath);
 byte[] buffer = new byte[1024];
 int bytesRead;
 while ((bytesRead = inputStream.read(buffer)) != -1) {
      outputStream.write(buffer, 0, bytesRead);
 }
 // 注意：这里缺少关闭资源的代码

解决方案1：使用try-catch-finally，在finally语句块中关闭资源(一般还是会被Fortofy扫描出来)

        FileInputStream inputStream = null;
        FileOutputStream outputStream = null;
        try {
            inputStream = new FileInputStream(sourcePath);
            outputStream = new FileOutputStream(destinationPath);
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
        } catch (IOException e) {
            e.printStackTrace();
        } finally {
            try {
                if (inputStream != null) {
                    inputStream.close();
                }
                if (outputStream != null) {
                    outputStream.close();
                }
            } catch (IOException e) {
                e.printStackTrace();
            }
        }

解决方案2：使用try-with-resources方式解决(不会被Fortofy检测出漏洞)

        try-with-resources大家不太常见，格式就是在try与catch语句块之间加入小括号，我们在小括号之中编写开启文件流代码，try-with-resources会为我们管理文件流，大伙儿无需手动关闭流资源。强烈推荐使用！增加代码可读性和行数，也会避免犯错。
 

    try (
            FileInputStream inputStream = new FileInputStream(sourcePath);
            FileOutputStream outputStream = new FileOutputStream(destinationPath)
        ) {
            byte[] buffer = new byte[1024];
            int bytesRead;
            while ((bytesRead = inputStream.read(buffer)) != -1) {
                outputStream.write(buffer, 0, bytesRead);
            }
        } // try-with-resources 会自动关闭资源
    }

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