Hi folks:
Before Dubbo2.7 does not support the configuration center, the way to get the
system configuration parameters is mainly through the getProperty(String key,
String defaultValue) and getProperty(String key) methods provided by
org.apache.dubbo.common.utils.ConfigUtils.
Sample inventory code:
```java
/ / Get the logback log level
ConfigUtils.getProperty("dubbo.logback.level");
/ / Configure the number of shared connections
ConfigUtils.getProperty("shareconnections","1");
```
Dubbo2.7 provides `org.apache.dubbo.common.config.ConfigurationUtils` to
support loading configurations from multiple configuration sources.
Sample inventory code:
```java
/ / Get the log4j log level
ConfigurationUtils.getProperty("dubbo.log4j.level");
/ / Get the service outage timeout
ConfigurationUtils.getServerShutdownTimeout()
```
risk point:
1. After the configuration center is introduced in 2.7, you can configure the
parameters of the application granularity in the configuration center. Some of
the original parameters are obtained by using ConfigUtils, which may invalidate
the user configuration.
2. There are different styles of obtaining application parameters in the
inventory code. For example, the log level log4j and logback use different APIs.
improve proposals:
1. First mark the version of ConfigUtils as expired, modify the implementation
of ConfigUtils, and use ConfigurationUtils to bridge to ConfigUtils.
2. Avoid using ConfigUtils in future developments, avoiding directly getting
Environment.getInstant.getConfiguration() and undoing ConfigurationUtils.
3. ConfigurationUtils should not contain a specific business method. It only
provides get/set methods for configuration parameters, such as the existing
getServerShutdownTimeout(), which should be passed in by the business scenario:
getProperty("dubbo.server.shutdown.timeout" ).
I will do some improvement for these risk point.
——
在 Dubbo2.7 未支持配置中心之前，获取系统配置参数的方式主要是通过 org.apache.dubbo.common.utils.ConfigUtils
提供的 getProperty(String key, String defaultValue)，getProperty(String key) 方法。
存量代码示例：
// 获取 logback 日志级别
ConfigUtils.getProperty("dubbo.logback.level");
// 配置共享连接的数量
ConfigUtils.getProperty("shareconnections","1");
Dubbo2.7 提供了 org.apache.dubbo.common.config.ConfigurationUtils 支持从多种配置源中加载配置
存量代码示例：
// 获取 log4j 日志级别
ConfigurationUtils.getProperty("dubbo.log4j.level");
// 获取服务停机超时时间
ConfigurationUtils.getServerShutdownTimeout()
风险点：
在 2.7 推出配置中心之后，允许用户在配置中心中配置应用粒度的参数，原有的一些参数使用了 ConfigUtils 去获取，可能导致用户配置失效。
存量代码中多处获取应用参数的代码风格不一，如获取日志级别 log4j 和 logback 使用了不同的 api。
改进方案：
首先将就版本的 ConfigUtils 标注为过期，修改 ConfigUtils 的实现，使用 ConfigurationUtils 桥接到
ConfigUtils。
今后开发中避免使用 ConfigUtils，避免直接获取 Environment.getInstant.getConfiguration()，统一走
ConfigurationUtils。
ConfigurationUtils 不应该包含具体某个业务方法，只提供配置参数的 get/set 方法，例如现有的
getServerShutdownTimeout()，应当由业务场景传入键值:
getProperty("dubbo.server.shutdown.timeout")。
