Segon
0%

解决WARN：No URLs will be polled as dynamic configuration sources.

Posted on Edited on

在spring boot中整合Eureka时，出现如下警告:

1
WARN 78340 --- [           main] c.n.c.sources.URLConfigurationSource     : No URLs will be polled as dynamic configuration sources.

解决方法

在src/main/resources/添加一个空的文件config.properties，如图
目录结构

原因

这个警告在类com.netflix.config.sources.URLConfigurationSource中，如下代码:

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
public URLConfigurationSource() {
  List<URL> urlList = new ArrayList();
  URL configFromClasspath = this.getConfigFileFromClasspath();
  if (configFromClasspath != null) {
    urlList.add(configFromClasspath);
  }

  String[] fileNames = getDefaultFileSources();
  if (fileNames.length != 0) {
    urlList.addAll(Arrays.asList(createUrls(fileNames)));
  }

  if (urlList.size() == 0) {
    this.configUrls = new URL[0];
    logger.warn("No URLs will be polled as dynamic configuration sources.");
    logger.info("To enable URLs as dynamic configuration sources, define System property archaius.configurationSource.additionalUrls or make " + DEFAULT_CONFIG_FILE_FROM_CLASSPATH + " available on classpath.");
  } else {
    this.configUrls = (URL[])urlList.toArray(new URL[urlList.size()]);
    logger.info("URLs to be used as dynamic configuration source: " + urlList);
  }
}

可以看到当urlList的size为0时，就会出现这个警告，然后urlList的来源有两个地方:
getConfigFileFromClasspath() 

1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
private URL getConfigFileFromClasspath() {
  URL url = null;
  ClassLoader loader = Thread.currentThread().getContextClassLoader();
  if (loader != null) {
    url = loader.getResource(DEFAULT_CONFIG_FILE_FROM_CLASSPATH);
  }

  if (url == null) {
    url = ClassLoader.getSystemResource(DEFAULT_CONFIG_FILE_FROM_CLASSPATH);
  }

  if (url == null) {
    url = URLConfigurationSource.class.getResource(DEFAULT_CONFIG_FILE_FROM_CLASSPATH);
  }

  return url;
}

DEFAULT_CONFIG_FILE_FROM_CLASSPATH的定义如下

1
2
3
4
public static final String DEFAULT_CONFIG_FILE_FROM_CLASSPATH =
    System.getProperty("archaius.configurationSource.defaultFileName") == null
        ? "config.properties"
        : System.getProperty("archaius.configurationSource.defaultFileName");

从如上代码我们可知 当archaius.configurationSource.defaultFileName属性存在时getConfigFileFromClasspath() 就通过指定的文件名获取文件，否则就获取config.properties文件。
getDefaultFileSources() 

1
2
3
4
5
6
7
8
9
10
11
private static final String[] getDefaultFileSources() {
  String name = System.getProperty("archaius.configurationSource.additionalUrls");
  String[] fileNames;
  if (name != null) {
    fileNames = name.split(",");
  } else {
    fileNames = new String[0];
  }

  return fileNames;
}

这段代码更简单，如果archaius.configurationSource.additionalUrls属性存在，就将它的值分割成String数组。

综上，如果同时满足如下条件将会产生警告：

  1. archaius.configurationSource.defaultFileName没有设置
  2. config.properties 文件不存在
  3. archaius.configurationSource.additionalUrls没有设置

所以我们的解决方案是创建config.properties文件破坏第2条，就不会有警告了，还有就是这个东西是在archaius-core这个依赖中，如果感兴趣可以自行去研究一下Netflix Archaius。