使用 try-with-resources 或在“finally”子句中关闭此“Stream”[重复]答案

【问题标题】：Use try-with-resources or close this 'Stream' ini a "finally" clause [duplicate]使用 try-with-resources 或在“finally”子句中关闭此“Stream”[重复]
【发布时间】：2022-02-07 19:18:06
【问题描述】：

我正在使用 Files.walk() 从目录中获取一些文件，但我收到了一个关于来自 sonarqube 和 sonarlint 的阻止程序错误的警告em> 代码分析那个

Connections, streams, files, and other classes that implement the Closeable interface or its super-interface, AutoCloseable, needs to be closed after use. Further, that close call must be made in a finally block otherwise an exception could keep the call from being made. Preferably, when class implements AutoCloseable, resource should be created using "try-with-resources" pattern and will be closed automatically.

代码如下：

Files.walk(Paths.get(ifRecordsPath))
                .filter(Files::isDirectory)
                .map(ifRecordsCollector)
                .map(ifRecordStreamAccumulator)
                .forEach(ifRecordCollection::addAll);

        return ifRecordCollection;

我读了这个post 并且几乎遇到了问题，但我不知道我是如何将流停止在正确的位置。当我添加 finally 块时，它仍然给出同样的错误

try {
            Files.walk(Paths.get(ifRecordsPath))
                    .filter(Files::isDirectory)
                    .map(ifRecordsCollector)
                    .map(ifRecordStreamAccumulator)
                    .forEach(ifRecordCollection::addAll);
        } finally {
            Files.walk(Paths.get(ifRecordsPath)).close();
        }

我该如何解决这个问题？

【问题讨论】：

方法调用不是变量！如果您调用Files.walk(Paths.get(ifRecordsPath)) 两次，您将创建两个不同的流。
你的代码在finally中创建了一个new流来关闭，你需要关闭原来的流。

标签： java spring java-stream try-catch-finally try-with-resources

【解决方案1】：

这意味着您需要将流保存到变量中，然后在 try-with-resources 中使用它或在 try-finally 中关闭它。所以要么这样：

try (Stream<Path> paths = Files.walk(Paths.get(ifRecordsPath))) {
    paths.filter(Files::isDirectory)
        .map(ifRecordsCollector)
        .map(ifRecordStreamAccumulator)
        .forEach(ifRecordCollection::addAll);
    return ifRecordCollection;
}

或者这个：

Stream<Path> paths = Files.walk(Paths.get(ifRecordsPath));
try {
    paths.filter(Files::isDirectory)
        .map(ifRecordsCollector)
        .map(ifRecordStreamAccumulator)
        .forEach(ifRecordCollection::addAll);
    return ifRecordCollection;
} finally {
    paths.close();
}

【讨论】：