之前在springboot学习之Starter中提到springboot官方提供了很多starter来实现自动配置，简化我们的开发，那么我们能不能把自己常用的一些组件也封装成一个starter来进行自动配置呢？答案是可以的，只要按照springboot自动配置的模式来写，就可以实现自己的starter,其实蛮简单的，下面我们来写一个简单的starter
pom.xml
<?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.peng</groupId>
<artifactId>helloword-spring-boot-starter</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>helloword-spring-boot-starter</name>
<description>Demo project for Spring Boot</description>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-autoconfigure</artifactId>
<version>1.5.4.RELEASE</version>
</dependency>
</dependencies>
<build>
<plugins>
<plugin>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-maven-plugin</artifactId>
</plugin>
</plugins>
</build>
</project>创建属性类
@ConfigurationProperties(prefix = "datasource")
public class DataSource {
private String driver;
private String url;
private String userName;
private String passWord;
public String getDriver() {
return driver;
}
public void setDriver(String driver) {
this.driver = driver;
}
public String getUrl() {
return url;
}
public void setUrl(String url) {
this.url = url;
}
public String getUserName() {
return userName;
}
public void setUserName(String userName) {
this.userName = userName;
}
public String getPassWord() {
return passWord;
}
public void setPassWord(String passWord) {
this.passWord = passWord;
}
}创建服务类
public class DataSourceService {
private DataSource dataSource;
public DataSourceService(DataSource dataSource){
this.dataSource = dataSource;
}
public String getDriver(){
return dataSource.getDriver();
}
public String getUrl(){
return dataSource.getUrl();
}
public String getUserName(){
return dataSource.getUserName();
}
public String getPassWord(){
return dataSource.getPassWord();
}
}创建自动配置类
@Configuration
@EnableConfigurationProperties(DataSource.class)
@ConditionalOnClass(DataSourceService.class)
@ConditionalOnProperty(prefix = "datasource",value = "enable",matchIfMissing = true)
public class DataSourceAutoConfiguration {
@Autowired
private DataSource dataSource;
@Bean
@ConditionalOnMissingBean(DataSourceService.class)
public DataSourceService dataSourceService(){
DataSourceService dataSourceService = new DataSourceService(dataSource);
return dataSourceService;
}
}说明：
@Configuration 表示当前是一个配置类
@EnableConfigurationProperties(DataSource.class) 表示开启DataSource类的配置
@ConditionalOnClass(DataSourceService.class) 表示当DataSourceService这个类在类路径中时，且当前容器中没有这个Bean的情况下，开始自动配置
@ConditionalOnProperty(prefix = “datasource”,value = “enable”,matchIfMissing = true) 表示指定的属性是否有指定的值
在resources/META-INF目录下创建spring.factories
org.springframework.boot.autoconfigure.EnableAutoConfiguration=com.peng.DataSourceAutoConfiguration至此，一个自定义的starter基本上已经完成了，下面是测试
执行mvn clean install命令，将starter安装到本地仓库中
新建一个springboot项目来测试一下我们自定义的starter
pom.xml文件中引用我们自已写的starter
<?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.example</groupId>
<artifactId>starter-demo</artifactId>
<version>0.0.1-SNAPSHOT</version>
<packaging>jar</packaging>
<name>starter-demo</name>
<description>Demo project for Spring Boot</description>
<parent>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-parent</artifactId>
<version>1.5.10.RELEASE</version>
<relativePath/>
</parent>
<dependencies>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter-web</artifactId>
</dependency>
<dependency>
<groupId>org.springframework.boot</groupId>
<artifactId>spring-boot-starter</artifactId>
</dependency>
<dependency>
<groupId>com.peng</groupId>
<artifactId>helloword-spring-boot-starter</artifactId>
<version>0.0.1-SNAPSHOT</version>
</dependency>
</dependencies>
</project>
添加属性到属性文件application.properties中
datasource.driver=oracle.jdbc.driver.OracleDriver
datasource.url=jdbc:oracle:thin:@localhost:1521:orcl
datasource.userName=root
datasource.passWord=123编写Controller类
@RestController
@SpringBootApplication
public class StarterDemoApplication {
@Autowired
DataSourceService dataSourceService;
@GetMapping("get/driver")
public String getDriver(){
return dataSourceService.getDriver();
}
@GetMapping("get/url")
public String getUrl(){
return dataSourceService.getUrl();
}
public static void main(String[] args) {
SpringApplication.run(StarterDemoApplication.class, args);
}
}在属性文件中加入debug=true，然后运行程序，可以看到所有自动配置的详细信息：
========================= AUTO-CONFIGURATION REPORT
=========================
Positive matches:
-----------------
## 可以看到自定义的starter已经包含在启动信息中，说明我们自己写的自动配置生效了
DataSourceAutoConfiguration#dataSourceService matched:
- @ConditionalOnMissingBean (types: com.peng.DataSourceService; SearchStrategy: all) did not find any beans (OnBeanCondition)
DispatcherServletAutoConfiguration matched:
- @ConditionalOnClass found required class 'org.springframework.web.servlet.DispatcherServlet'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition) - @ConditionalOnWebApplication (required) found StandardServletEnvironment (OnWebApplicationCondition)
DispatcherServletAutoConfiguration.DispatcherServletConfiguration matched:
- @ConditionalOnClass found required class 'javax.servlet.ServletRegistration'; @ConditionalOnMissingClass did not find unwanted class (OnClassCondition) - Default DispatcherServlet did not find dispatcher servlet beans (DispatcherServletAutoConfiguration.DefaultDispatcherServletCondition) ...
...下面省略
...在浏览器中输入：http://localhost:8080/get/url 可以看到配置的datasource.url信息
至此，我们自己的starter就完成了！！！