https://github.com/nacos-group/nacos-spring-project
Nacos ECO Project for Spring Framework
https://github.com/nacos-group/nacos-spring-project
distributed-configuration java nacos spring springframework
Last synced: about 1 month ago
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Nacos ECO Project for Spring Framework
- Host: GitHub
- URL: https://github.com/nacos-group/nacos-spring-project
- Owner: nacos-group
- License: apache-2.0
- Created: 2018-07-26T02:30:01.000Z (almost 7 years ago)
- Default Branch: develop
- Last Pushed: 2024-08-02T01:57:37.000Z (11 months ago)
- Last Synced: 2025-04-11T15:57:01.550Z (2 months ago)
- Topics: distributed-configuration, java, nacos, spring, springframework
- Language: Java
- Homepage: https://nacos.io/
- Size: 1.3 MB
- Stars: 762
- Watchers: 62
- Forks: 309
- Open Issues: 62
-
Metadata Files:
- Readme: README.md
- License: LICENSE
Awesome Lists containing this project
README
Nacos Spring Project
=================================
[](https://travis-ci.org/nacos-group/nacos-spring-project)
[Nacos](https://github.com/alibaba/nacos) is an open source project for discovering, configuring and managing cloud-native applications. Key features of Nacos include:
- Service Discovery and Service Health Check
- Dynamic Configuration Management
- Dynamic DNS Service
- Service and Metadata Management
[Nacos Spring Project](https://github.com/nacos-group/nacos-spring-project), which is based on [Nacos](https://github.com/alibaba/nacos), fully embraces the Spring ecosystem and is designed to help you build Spring applications rapidly.
The project contains a core module named [`nacos-spring-context`](nacos-spring-context). It enables you to expand modern Java programming models in the following ways:
- [Annotation-Driven](#41-annotation-driven)
- [Dependency Injection](#42-dependency-injection)
- [Externalized Configuration](#43-externalized-configuration)
- [Event-Driven](#44-eventlistener-driven)
These features strongly depend on Spring Framework 3.2+ API, and can be seamlessly integrated with any Spring Stack, such as Spring Boot and Spring Cloud.
**Note:** We recommend that you use annotation-driven programming, even though XML-based features also work.
Content
===============================
- [1. Samples](#1-samples)
- [1.1. Samples](#11-samples)
- [1.2. How To Run the Samples](#12-how-to-run-the-samples)
- [2. Dependencies & Compatibility](#2-dependencies--compatibility)
- [3. Quickstart](#3-quickstart)
- [3.1. Prerequisite](#31-prerequisite)
- [3.2. Enable Nacos](#32-enable-nacos)
- [3.3. Enable configuration service](#33-enable-configuration-service)
- [3.4. Enable Service Discovery](#34-enable-service-discovery)
- [4. Core Features](#4-core-features)
- [4.1. Annotation-Driven](#41-annotation-driven)
- [4.1.1. Enable Nacos](#411-enable-nacos)
- [4.1.2. Configure Change Listener method](#412-configure-change-listener-method)
- [4.1.2.1. Type Conversion](#4121-type-conversion)
- [4.1.2.1.1. Type Conversion during YAML Parsing](#41211-Type Conversion during YAML Parsing)
- [4.1.2.2. Timeout of Execution](#4122-timeout-of-execution)
- [4.1.3. Global and Special Nacos Properties](#413-global-and-special-nacos-properties)
- [4.1.4. `@NacosProperties`](#414-nacosproperties)
- [4.2. Dependency Injection](#42-dependency-injection)
- [4.3. Externalized Configuration](#43-externalized-configuration)
- [4.4. Event/Listener Driven](#44-eventlistener-driven)
- [5. Modules](#5-modules)
- [6. Relative Projects](#6-relative-projects)
# 1. Samples
Included in this section are some samples for you to get a quick start with Nacos Spring.
## 1.1. Samples
- [Dependency Injection Sample of `@NacosInjected`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/NacosConfiguration.java)
- [Simple Sample of `@NacosConfigListener`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/listener/SimpleNacosConfigListener.java)
- [Type Conversion Sample of `@NacosConfigListener`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/listener/PojoNacosConfigListener.java)
- [Timeout Sample of `@NacosConfigListener`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/listener/TimeoutNacosConfigListener.java)
- [Sample of `@NacosConfigurationProperties`/`@NacosProperty`/`@NacosIgnore`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/properties/NacosConfigurationPropertiesConfiguration.java)
- [Sample of `@NacosPropertySources`/`@NacosPropertySource`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/env/NacosPropertySourceConfiguration.java)
- [Event/Listener Sample](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/event/NacosEventListenerConfiguration.java)
## 1.2. How To Run the Samples
Take the Spring Web MVC project for example:
1. Check out the source code of `nacos-spring-project` :
` $ git clone [email protected]:nacos-group/nacos-spring-project.git`
2. Build your source code with Maven:
`$ mvn clean package`
3. Run Spring Web MVC Samples:
`$ java -jar target/nacos-spring-webmvc-sample.war`
# 2. Dependencies & Compatibility
The following table shows the dependencies and compatabilities of Nacos Spring Project.
| Dependencies | Compatibility |
| -------------- | ------------- |
| Java | 1.8+ |
| Spring Context | 3.2+ |
| [Alibaba Spring Context Support](https://github.com/alibaba/spring-context-support) | 1.0.1+ |
| [Alibaba Nacos](https://github.com/alibaba/nacos) | 1.1.1+ |
# 3. Quickstart
This quickstart shows you how to enable Nacos and its service discovery and configuration management features in your Spring project.
## 3.1. Prerequisite
Before you configure your Spring project to use Nacos, you need to start a Nacos server in the backend. Refer to [Nacos Quick Start](https://nacos.io/en-us/docs/quick-start.html) for instructions on how to start a Nacos server.
## 3.2. Enable Nacos
Complete the following steps to enable Nacos for your Spring project.
1. Add [`nacos-spring-context`](nacos-spring-context) in your Spring application's dependencies:
```xml
...
com.alibaba.nacos
nacos-spring-context
1.1.0
...
```
**Note:** Support Spring 5 from version 0.2.3-RC1, support Spring 6 from version 2.1.0.
2. Add the `@EnableNacos` annotation in the `@Configuration` class of Spring and specify "\${host}:${port}" of your Nacos server in the `serverAddr` attribute:
```java
@Configuration
@EnableNacos(
globalProperties =
@NacosProperties(serverAddr = "${nacos.server-addr:localhost:12345}")
)
public class NacosConfiguration {
...
}
```
## 3.3. Enable configuration service
Now you would like to use the confguration service of Nacos. Simply use **Dependency Injection** to inject `ConfigService` instance in your Spring Beans when `@EnableNacos` is annotated, as shown below:
```java
@Service
public class ConfigServiceDemo {
@NacosInjected
private ConfigService configService;
public void demoGetConfig() {
try {
String dataId = "{dataId}";
String group = "{group}";
String content = configService.getConfig(dataId, groupId, 5000);
System.out.println(content);
} catch (NacosException e) {
e.printStackTrace();
}
}
...
}
```
`ConfigService` is the key interface of Nacos which helps you to get or publish configurations.
The following code achieves the same effect:
```java
try {
// Initialize the configuration service, and the console automatically obtains the following parameters through the sample code.
String serverAddr = "{serverAddr}";
String dataId = "{dataId}";
String group = "{group}";
Properties properties = new Properties();
properties.put("serverAddr", serverAddr);
ConfigService configService = NacosFactory.createConfigService(properties);
// Actively get the configuration.
String content = configService.getConfig(dataId, group, 5000);
System.out.println(content);
} catch (NacosException e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
```
## 3.4. Enable Service Discovery
If you would also like to use the service discovery feature of Nacos, you can inject a `NamingService` instance for service discovery:
```java
@NacosInjected
private NamingService namingService;
```
For details about the usages of `ConfigService` and `NamingService`, please refer to [Nacos SDK](https://nacos.io/en-us/docs/sdk.html).
# 4. Core Features
This section provides a detailed description of the key features of [`nacos-spring-context`](nacos-spring-context):
- [Annotation-Driven](#annotation-driven)
- [Dependency Injection](#dependency-injection)
- [Externalized Configuration](#externalized-configuration)
- [Event-Driven](#eventlistener-driven)
## 4.1. Annotation-Driven
### 4.1.1. Enable Nacos
`@EnableNacos` is a modular-driven annotation that enables all features of Nacos Spring, including **Service Discovery** and **Distributed Configuration**. It equals to `@EnableNacosDiscovery` and
`@EnableNacosConfig`, which can be configured separately and used in different scenarios.
### 4.1.2. Configure Change Listener method
Suppose there was a config in Nacos Server whose `dataId` is "testDataId" and `groupId` is default group("DEFAULT_GROUP"). Now you would like to change its content by using the `ConfigService#publishConfig` method:
```java
@NacosInjected
private ConfigService configService;
@Test
public void testPublishConfig() throws NacosException {
configService.publishConfig(DATA_ID, DEFAULT_GROUP, "9527");
}
```
Then you would like to add a listener, which will be listening for the config changes. You can do this by adding a config change listener method into your Spring Beans:
```java
@NacosConfigListener(dataId = DATA_ID)
public void onMessage(String config) {
assertEquals("mercyblitz", config); // asserts true
}
```
The code below has the same effect:
```java
configService.addListener(DATA_ID, DEFAULT_GROUP, new AbstractListener() {
@Override
public void receiveConfigInfo(String config) {
assertEquals("9527", config); // asserts true
}
});
```
**Note:** `@NacosConfigListener` supports richer type conversions.
- See [Simple Sample of `@NacosConfigListener`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/listener/SimpleNacosConfigListener.java)
#### 4.1.2.1. Type Conversion
The type conversion of `@NacosConfigListener` includes both build-in and customized implementations. By default, build-in type conversion is based on Spring `DefaultFormattingConversionService`, which means it covers most of the general cases as well as the rich features of the higher Spring framework.
For example, the content "9527" in the preceding example can also be listened by a method with integer or the `Integer` argument:
```java
@NacosConfigListener(dataId = DATA_ID)
public void onInteger(Integer value) {
assertEquals(Integer.valueOf(9527), value); // asserts true
}
@NacosConfigListener(dataId = DATA_ID)
public void onInt(int value) {
assertEquals(9527, value); // asserts true
}
```
Of course, [`nacos-spring-context`](nacos-spring-context) provides elastic extension for developers. If you define a named `nacosConfigConversionService` Spring Bean whose type is `ConversionService` , the `DefaultFormattingConversionService` will be ignored. In addition, you can customize the implementation of the `NacosConfigConverter` interface to specify a listener method for type conversion:
```java
public class UserNacosConfigConverter implements NacosConfigConverter {
@Override
public boolean canConvert(Class targetType) {
return true;
}
@Override
public User convert(String source) {
return JSON.parseObject(source, User.class);
}
}
```
The `UserNacosConfigConverter` class binds the `@NacosConfigListener.converter()` attribute:
```java
@NacosInjected
private ConfigService configService;
@Test
public void testPublishUser() throws NacosException {
configService.publishConfig("user", DEFAULT_GROUP, "{\"id\":1,\"name\":\"mercyblitz\"}");
}
@NacosConfigListener(dataId = "user", converter = UserNacosConfigConverter.class)
public void onUser(User user) {
assertEquals(Long.valueOf(1L), user.getId());
assertEquals("mercyblitz", user.getName());
}
```
##### 4.1.2.1.1. Type Conversion during YAML Parsing
By default, starting from version 1.1.2, this library uses `SafeConstructor` for type conversion during YAML parsing. This is done to ensure that potentially unsafe code is not executed during the parsing process. `SafeConstructor` provides a secure construction logic for mapping YAML structures to Java objects.
**System Property Toggle**
To maintain compatibility with versions prior to 1.1.2, we have introduced a system property toggle named `yamlAllowComplexObject`. Prior to version 1.1.2, the library defaulted to using `Constructor`, another constructor in the SnakeYAML library that supports more complex object mapping. Starting from version 1.1.2, the default is switched to `SafeConstructor`.
**Potential Risks**
It's important to note that enabling `Constructor` introduces some potential risks, particularly the risk of Remote Code Execution (`RCE`). This is because `Constructor` allows more flexible object construction, but it also increases the risk of handling malicious YAML input.
**Recommendations**
- We recommend using the `NacosConfigConverter` for custom conversions.
**If You Must Use `Constructor`**
- Ensure that the source of the YAML data is secure.
**How to Disable `SafeConstructor`**
You can set the toggle by adding a JVM system property when starting your application. For example, in the command line:
```bash
java -DyamlAllowComplexObject=true -jar your-application.jar
```
- See [Type Conversion Sample of `@NacosConfigListener`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/listener/PojoNacosConfigListener.java)
#### 4.1.2.2. Timeout of Execution
As it might cost some time to run customized `NacosConfigConverter`, you can set max execution time in the `@NacosConfigListener.timeout()` attribute to prevent it from blocking other listeners:
```java
@Configuration
public class Listeners {
private Integer integerValue;
private Double doubleValue;
@NacosConfigListener(dataId = DATA_ID, timeout = 50)
public void onInteger(Integer value) throws Exception {
Thread.sleep(100); // timeout of execution
this.integerValue = value;
}
@NacosConfigListener(dataId = DATA_ID, timeout = 200)
public void onDouble(Double value) throws Exception {
Thread.sleep(100); // normal execution
this.doubleValue = value;
}
public Integer getIntegerValue() {
return integerValue;
}
public Double getDoubleValue() {
return doubleValue;
}
}
```
The `integerValue` of `Listeners` Bean is always `null` and will not be changed. Therefore, those asserts will be `true`:
```java
@Autowired
private Listeners listeners;
@Test
public void testPublishConfig() throws NacosException {
configService.publishConfig(DATA_ID, DEFAULT_GROUP, "9527");
assertNull(listeners.getIntegerValue()); // asserts true
assertEquals(Double.valueOf(9527), listeners.getDoubleValue()); // asserts true
}
```
- See [Timeout Sample of `@NacosConfigListener`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/listener/TimeoutNacosConfigListener.java)
### 4.1.3. Global and Special Nacos Properties
The `globalProperties` is a required attribute in any `@EnableNacos`, `@EnableNacosDiscovery` or `@EnableNacosConfig`, and its type is `@NacosProperties`. `globalProperties` initializes "**Global Nacos Properties**" that will be used by other annotations
and components, e,g `@NacosInjected`. In other words, **Global Nacos Properties**" defines the global and default properties. It is set with the lowest priority and can be overridden if needed. The precedence of overiding rules is shown in the following table:
| Precedence Order | Nacos Annotation | Required |
| ---------------- | ------------------------------------------------------------ | -------- |
| 1 | `*.properties()` | N |
| 2 | `@EnableNacosConfig.globalProperties()` or `@EnableNacosDiscovery.globalProperties()` | Y |
| 3 | `@EnableNacos.globalProperties()` | Y |
`*.properties()` defines special Nacos properties which come from one of the following:
- `@NacosInjected.properties()`
- `@NacosConfigListener.properties()`
- `@NacosPropertySource.properties()`
- `@NacosConfigurationProperties.properties()`
Special Nacos properties are also configured by `@NacosProperties`. However, they are optional and are used to override Global Nacos Properties in special scenarios. If not defined, the Nacos Properties will
try to retrieve properities from `@EnableNacosConfig.globalProperties()` or `@EnableNacosDiscovery.globalProperties()`, or
`@EnableNacos.globalProperties()`.
### 4.1.4. `Nacos Properties`
`@NacosProperties` is a uniform annotation for global and special Nacos properties. It serves as a mediator between Java `Properties` and `NacosFactory` class. `NacosFactory` is responsible for creating `ConfigService` or `NamingService` instances.
The attributes of `@NacosProperties` completely support placeholders whose source is all kinds of `PropertySource` in Spring `Environment` abstraction, typically Java System `Properties` and OS environment variables. The prefix of all placeholders are `nacos.`. The mapping between the attributes of `@NacosProperties` and Nacos properties are shown below:
| Attribute | Property | Placeholder | Description | Required |
| --------------- | -------------- | ------------------------ | ----------- | --------- |
| `endpoint()` | `endpoint` | `${nacos.endpoint:}` | | N |
| `namespace()` | `namespace` | `${nacos.namespace:}` | | N |
| `accessKey()` | `access-key` | `${nacos.access-key:}` | | N |
| `secretKey()` | `secret-key` | `${nacos.secret-key:}` | | N |
| `serverAddr()` | `server-addr` | `${nacos.server-addr:}` | | Y |
| `contextPath()` | `context-path` | `${nacos.context-path:}` | | N |
| `clusterName()` | `cluster-name` | `${nacos.cluster-name:}` | | N |
| `encode()` | `encode` | `${nacos.encode:UTF-8}` | | N |
Note that there are some differences in the placeholders of `globalProperties()` between `@EnableNacosDiscovery` and `@EnableNacosConfig`:
| Attribute | `@EnableNacosDiscovery`'s Placeholder |`@EnableNacosConfig`'s Placeholder |
| --------------- | -------------------------------------------------------- | ------------------------------------------------- |
| `endpoint()` | `${nacos.discovery.endpoint:${nacos.endpoint:}}` |`${nacos.config.endpoint:${nacos.endpoint:}}` |
| `namespace()` | `${nacos.discovery.namespace:${nacos.namespace:}}` |`${nacos.config.namespace:${nacos.namespace:}}` |
| `accessKey()` | `${nacos.discovery.access-key:${nacos.access-key:}}` |`${nacos.config.access-key:${nacos.access-key:}}` |
| `secretKey()` | `${nacos.discovery.secret-key:${nacos.secret-key:}}` |`${nacos.config.secret-key:${nacos.secret-key:}}` |
| `serverAddr()` | `${nacos.discovery.server-addr:${nacos.server-addr:}}` | `${nacos.config.server-addr:${nacos.server-addr:}}` |
| `contextPath()` | `${nacos.discovery.context-path:${nacos.context-path:}}` | `${nacos.config.context-path:${nacos.context-path:}}` |
| `clusterName()` | `${nacos.discovery.cluster-name:${nacos.cluster-name:}}` |`${nacos.config.cluster-name:${nacos.cluster-name:}}` |
| `encode()` | `${nacos.discovery.encode:${nacos.encode:UTF-8}}` |`${nacos.config.encode:${nacos.encode:UTF-8}}` |
These placeholders of `@EnableNacosDiscovery` and `@EnableNacosConfig` are designed to isolate different Nacos servers, and are unnecessary in most scenarios. By default, general placeholders will be reused.
## 4.2. Dependency Injection
`@NacosInjected` is a core annotation which is used to inject `ConfigService` or `NamingService` instance in your Spring Beans and make these instances **cacheable**. This means the instances will be the same if their `@NacosProperties` are equal, regargless of whether the properties come from global or special Nacos properties:
```java
@NacosInjected
private ConfigService configService;
@NacosInjected(properties = @NacosProperties(encode = "UTF-8"))
private ConfigService configService2;
@NacosInjected(properties = @NacosProperties(encode = "GBK"))
private ConfigService configService3;
@NacosInjected
private NamingService namingService;
@NacosInjected(properties = @NacosProperties(encode = "UTF-8"))
private NamingService namingService2;
@NacosInjected(properties = @NacosProperties(encode = "GBK"))
private NamingService namingService3;
@Test
public void testInjection() {
Assert.assertEquals(configService, configService2);
Assert.assertNotEquals(configService2, configService3);
Assert.assertEquals(namingService, namingService2);
Assert.assertNotEquals(namingService2, namingService3);
}
```
The property `configService` uses `@EnableNacos#globalProperties()` or `@EnableNacosConfig#globalProperties()`, and because the default value of the `encode` attribute is “UTF-8”, therefore the `configService` instance and the `configService2` instance which is annotated by `@NacosProperties(encode = "UTF-8")` are the same. The same is true for `namingService` and `namingService2`.
More importantly, unlike the `ConfigService` instances created by the `NacosFactory.createConfigService()` method, the `ConfigService` instances created by the `@NacosInjected` annotation support Nacos Spring events. For instance, there will be an `NacosConfigPublishedEvent` after an enhanced `ConfigService` invokes the `publishConfig()` method. Refer to the [Event/Listener Driven](#eventlistener-driven) section for more details.
- See [Dependency Injection Sample](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/NacosConfiguration.java)
## 4.3. Externalized Configuration
Externalized configuration is a concept introduced by Spring Boot, which allows applications to receive external property sources to control runtime behavior. Nacos Server runs an isolation process outside the application to maintain the application configurations. [`nacos-spring-context`](nacos-spring-context) provides properties features including object binding, dynamic configuration(auto-refreshed) and so on, and dependence on Spring Boot or Spring Cloud framework is required.
Here is a simple comparison between [`nacos-spring-context`](nacos-spring-context) and Spring stack:
| Spring Stack | Nacos Spring | Highlight |
| -------------------------- | ------------------------------- | ---------------------------------------------- |
| `@Value` | `@NacosValue` | auto-refreshed |
| `@ConfigurationProperties` | `@NacosConfigurationProperties` | auto-refreshed,`@NacosProperty`,`@NacosIgnore` |
| `@PropertySource` | `@NacosPropertySource` | auto-refreshed, precedence order control |
| `@PropertySources` | `@NacosPropertySources` | |
- See [Auto-Refreshed Sample of `@NacosConfigurationProperties`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/properties/NacosConfigurationPropertiesConfiguration.java)
- See [Sample of `@NacosPropertySources` and `@NacosPropertySource`](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/env/NacosPropertySourceConfiguration.java)
## 4.4. Event/Listener Driven
Nacos Event/Listener Driven is based on the standard Spring Event/Listener mechanism. The `ApplicationEvent` of Spring is an abstract super class for all Nacos Spring events:
| Nacos Spring Event | Trigger |
| -------------------------------------------- | ------------------------------------------------------------ |
| `NacosConfigPublishedEvent` | After `ConfigService.publishConfig()` |
| `NacosConfigReceivedEvent` | After`Listener.receiveConfigInfo()` |
| `NacosConfigRemovedEvent` | After `configService.removeConfig()` |
| `NacosConfigTimeoutEvent` | `ConfigService.getConfig()` on timeout |
| `NacosConfigListenerRegisteredEvent` | After `ConfigService.addListner()` or `ConfigService.removeListener()` |
| `NacosConfigurationPropertiesBeanBoundEvent` | After `@NacosConfigurationProperties` binding |
| `NacosConfigMetadataEvent` | After Nacos Config operations |
- See [Event/Listener Sample](https://github.com/nacos-group/nacos-spring-project/blob/master/nacos-spring-samples/nacos-spring-webmvc-sample/src/main/java/com/alibaba/nacos/samples/spring/event/NacosEventListenerConfiguration.java)
# 5. Modules
- [`nacos-spring-context`](nacos-spring-context)
- [`nacos-spring-samples`](nacos-spring-samples)
# 6. Relative Projects
- [Alibaba Nacos](https://github.com/alibaba/nacos)
- [Alibaba Spring Context Support](https://github.com/alibaba/spring-context-support)