聲納錯誤：使用try-with-resources或在“finally”子句中關閉此“ZipOutputStream”

我用 Java 在 Spring Boot 應用程式中實作了一個 zip 下載方法。我嘗試了幾種不同的解決方案，但我仍然收到：使用 try-with-resources 或在來自聲納的“finally”子句錯誤中關閉此“ZipOutputStream”。

在這里你可以找到我在服務中的實作。如果你能指導我解決這個問題，我會很高興！

@Override
public void downloadZipBySeasonId(int seasonId, HttpServletResponse response) throws IOException {
.
.
.
    if(!items.isEmpty()) {
        ZipOutputStream zipOut = null;
        try {
            zipOut = new ZipOutputStream(response.getOutputStream());  // Sonar points this line!
            for (int i = 1; i <= items.size(); i  ) {
                LetterEntity letter = items.get(i - 1);
                ZipEntry zipEntry = new ZipEntry(letter.getLetterName());
                zipOut.putNextEntry(zipEntry);
                StreamUtils.copy(letter.getLetterContent(), zipOut);
                zipOut.closeEntry();
            }
        }
        catch (IOException e) {
            e.printStackTrace();
            throw new IllegalArgumentException("Could not zip succesfully!");
        }
        finally {
            if(zipOut != null) {
                zipOut.finish();
                zipOut.close();
            }
        }
        response.setStatus(HttpServletResponse.SC_OK);
        response.addHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\""   zipFileName   "\"");
    } else {
        response.setStatus(HttpServletResponse.SC_NO_CONTENT);
    }
}

uj5u.com熱心網友回復：

嘗試使用資源自動關閉資源（資源如 Streams ，Buffereds ..）您不需要關閉 finally 塊中的讀取器或寫入器，您不需要撰寫 finally 塊，也可以避免撰寫 catch 塊..

例子

 try (BufferedReader r = Files.newBufferedReader(path1);
  BufferedWriter w = Files.newBufferedWriter(path2))
 {
  //protected code
 }
 catch (Exception e) {
  // exeption handler
 } 

檔案：https : //docs.oracle.com/javase/tutorial/essential/exceptions/tryResourceClose.html

uj5u.com熱心網友回復：

Try with resources 是一個非常漂亮的概念，它消除了在 finally 塊中關閉資源的痛苦，這也是您撰寫的幾行額外代碼。Try with resources 會自動關閉資源，使您的代碼簡潔，并在任何情況下都負責關閉資源。

句法：

    Scanner scanner = null;
try {
    scanner = new Scanner(new File("scan.txt"));
    while (scanner.hasNext()) {
        System.out.println(scanner.nextLine());
    }
} catch (FileNotFoundException e) {
    e.printStackTrace();
} finally {
    if (scanner != null) {
        scanner.close();
    }
}

嘗試使用資源：

    try (Scanner scanner = new Scanner(new File("scan.txt"))) {
    while (scanner.hasNext()) {
        System.out.println(scanner.nextLine());
    }
} catch (FileNotFoundException fnfe) {
    fnfe.printStackTrace();
}

uj5u.com熱心網友回復：

將 try with resources 應用到初始代碼如下。在這里，您不必在 finally 塊中關閉流。當 try catch 塊退出時它關閉。由于空檢查，存在聲納問題。

 if(!items.isEmpty()) {
        
        try (ZipOutputStream zipOut = new ZipOutputStream(response.getOutputStream());){
            for (int i = 1; i <= items.size(); i  ) {
                LetterEntity letter = items.get(i - 1);
                ZipEntry zipEntry = new ZipEntry(letter.getLetterName());
                zipOut.putNextEntry(zipEntry);
                StreamUtils.copy(letter.getLetterContent(), zipOut);
                zipOut.closeEntry();
            }
        }
        catch (IOException e) {
            e.printStackTrace();
            throw new IllegalArgumentException("Could not zip succesfully!");
        }

        response.setStatus(HttpServletResponse.SC_OK);
        response.addHeader(HttpHeaders.CONTENT_DISPOSITION, "attachment; filename=\""   zipFileName   "\"");
    } else {
        response.setStatus(HttpServletResponse.SC_NO_CONTENT);
    }

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