Spring Boot 自定义starter

创建一个用maven构建的springboot项目



pom文件配置如下：

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>

<groupId>com.xjw.springboot</groupId>
<artifactId>hellostarter</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>hello-spring-boot-starter</name>
<description>测试自定义starter</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath/> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-configuration-processor</artifactId>
<optional>true</optional>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>

定义一个pojo用来接收properties中配置的信息

1 package com.xjw;
2
3 import org.springframework.boot.context.properties.ConfigurationProperties;
4
5 @ConfigurationProperties(prefix = "hello")
6 public class HelloServiceProperteis {
7
8     private String msg;
9
10     public String getMsg() {
11         return msg;
12     }
13
14     public void setMsg(String msg) {
15         this.msg = msg;
16     }
17
18 }
19

@ConfigurationProperties：用来标识这个pojo是一个用来接收指定前缀的资源配置值

prefix：表示在配置文件中配置项前缀

编写一个Service用来对外提供服务

package com.xjw;

public class HelloService {

private String msg;

public String sayHello() {
return "Hello " + msg;
}

public String getMsg() {
return msg;
}

public void setMsg(String msg) {
this.msg = msg;
}

}

配置一个pojo用来读取上面配置的 HelloServiceProperteis 

package com.xjw;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.autoconfigure.condition.ConditionalOnClass;
import org.springframework.boot.autoconfigure.condition.ConditionalOnMissingBean;
import org.springframework.boot.autoconfigure.condition.ConditionalOnProperty;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;

@Configuration
@EnableConfigurationProperties(value = HelloServiceProperteis.class)
@ConditionalOnClass(HelloService.class)
@ConditionalOnProperty(prefix = "hello", value = "enable", matchIfMissing = true)
public class HelloAutoConfiguration {

@Autowired
private HelloServiceProperteis helloServiceProperteis;

@Bean
@ConditionalOnMissingBean(HelloService.class)
public HelloService helloService() {
HelloService helloService = new HelloService();
helloService.setMsg(helloServiceProperteis.getMsg());
return helloService;
}
}

@Configuration：标识此类为一个spring配置类

@EnableConfigurationProperties(value = HelloServiceProperteis.class):启动配置文件，value用来指定我们要启用的配置类，可以有多个，多个时我们可以这么写value={xxProperties1.class,xxProperteis2.class....}

@ConditionalOnClass(HelloService.class):表示当classPath下存在HelloService.class文件时改配置文件类才有效

@ConditionalOnProperty(prefix = "hello", value = "enable", matchIfMissing = true):表示只有我们的配置文件是否配置了以hello为前缀的资源项值，并且在该资源项值为enable，如果没有配置我们默认设置为enable

最后在src/main/resources 文件夹下新建文件夹 META-INF，在新建的META-INF文件夹下新建 spring.factories



在新建的spring.factories文件中配置自动启动类为我们之前编写的 HelloAutoConfiguration 类

org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.xjw.HelloAutoConfiguration



然后就可以在其他的spring-boot项目中使用我们刚刚新建的starter了,我们来测试一下

在新建一个spring-boot项目，pom.xml配置如下: 

<?xml version="1.0" encoding="UTF-8"?>
<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/xsd/maven-4.0.0.xsd"> <modelVersion>4.0.0</modelVersion>

<groupId>com.xjw.springboot</groupId>
<artifactId>hellostarter.test</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>

<name>hello-spring-boot-starter-test</name>
<description>测试自定义starter</description>

<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.2.RELEASE</version>
<relativePath /> <!-- lookup parent from repository -->
</parent>

<properties>
<project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
<project.reporting.outputEncoding>UTF-8</project.reporting.outputEncoding>
<java.version>1.8</java.version>
</properties>

<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>

<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-test</artifactId>
<scope>test</scope>
</dependency>

<dependency>
<groupId>com.xjw.springboot</groupId>
<artifactId>hellostarter</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-devtools</artifactId>
</dependency>
</dependencies>

<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>

</project>

  然后我们直接在咋们的启动类中中尝试使用以下我们上面定义的starter提供的HelloService:

package com.xjw;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;

@RestController
@SpringBootApplication
public class HelloSpringBootStarterTestApplication {

@Autowired
private HelloService helloService;

@RequestMapping("/")
public String index() {
return helloService.sayHello();
}

public static void main(String[] args) {
SpringApplication.run(HelloSpringBootStarterTestApplication.class, args);
}
}

 接着我们修改测试项目中的application.properteis，加入如下配置：

debug=true
server.port=8888

#hello=enable
hello.msg=测试starter

 最后启动项目，观察控制台输出的内容中依赖的starter,从Positive matches下我们可以看到有这么一句：

HelloAutoConfiguration matched:
- @ConditionalOnClass found required class 'com.xjw.HelloService'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition)
- @ConditionalOnProperty (hello.enable) matched (OnPropertyCondition)

或者我们打开项目依赖树也能找到我们的starter ,这说明spring已经自动的启动了我们的starter了，打开浏览器输入地址：http://localhost:8888/将会看到如下结果

 


转自： http://www.cnblogs.com/cz-xjw/p/6632402.html