Question

如何确保此方法关闭OutputStream以避免内存泄漏？

public static void store(Properties properties, Class script) throws IOException {
    ScriptManifest scriptManifest = (ScriptManifest) script.getAnnotation(ScriptManifest.class);
    if (scriptManifest != null) {
        String name = scriptManifest.name();
        FileOutputStream outputStream = new FileOutputStream(Constants.SCRIPT_PROPERTIES_DIR + File.separator + name + ".properties");
        properties.store(outputStream, "");
        outputStream.close();
    } else {
        throw new RuntimeException("Script " + script.getName() + " does not have a ScriptManifest.");
    }
}

Answer 1

您可以使用try-with-resources。例如：

public static void store(Properties properties, Class script) throws IOException {
    ScriptManifest scriptManifest = (ScriptManifest) script.getAnnotation(ScriptManifest.class);
    if (scriptManifest != null) {
        String name = scriptManifest.name();
        try ( FileOutputStream outputStream = new FileOutputStream(Constants.SCRIPT_PROPERTIES_DIR + File.separator + name + ".properties") ) {
            properties.store(outputStream, "");
        }
    } else {
        throw new RuntimeException("Script " + script.getName() + " does not have a ScriptManifest.");
    }
}

或尝试使用finally块：

public static void store(Properties properties, Class script) throws IOException {
    ScriptManifest scriptManifest = (ScriptManifest) script.getAnnotation(ScriptManifest.class);
    if (scriptManifest != null) {
        String name = scriptManifest.name();
        FileOutputStream outputStream = null;
        try {
            outputStream = new FileOutputStream(Constants.SCRIPT_PROPERTIES_DIR + File.separator + name + ".properties");
            properties.store(outputStream, "");
        } finally {
            if ( outputStream != null ) outputStream.close();
        }
    } else {
        throw new RuntimeException("Script " + script.getName() + " does not have a ScriptManifest.");
    }
}

Answer 2

有两种方法。

FileOutputStream outputStream = null;
try {
  outputStream = new FileOutputStream(...)
  ...
 }
 catch (IOException e) {
    throw new RuntimeException(...)
 }
 finally {
    // or use the Apache Commons IOUtils.closeQuietly(outputStream);
    // and then only need the one line
    if (outputStream != null) {
      try {
         outputStream.close();
      }
      catch (Exception ignore) { }
    }
 }

在Java的更高版本中，您可以使用try-with-resources

try (FileOutputStream fos = new FileOutputStream("f:/tmp/stops.csv")) {
}
catch (IOException e) {
}

如何确保此方法关闭输出流？

2 个答案: