Spring Boot 自定义 starter

时间  2019-12-04
标签 spring boot 自定义 starter 栏目 Spring 繁體版
原文   原文链接

1、简介

SpringBoot 最强大的功能就是把咱们经常使用的场景抽取成了一个个starter（场景启动器），咱们经过引入springboot 为我提供的这些场景启动器，咱们再进行少许的配置就能使用相应的功能。即便是这样，springboot也不能囊括咱们全部的使用场景，每每咱们须要自定义starter，来简化咱们对springboot的使用。java

2、如何自定义starter

1.实例

如何编写自动配置 ？

咱们参照@WebMvcAutoConfiguration为例，咱们看看们须要准备哪些东西，下面是WebMvcAutoConfiguration的部分代码：git

@Configuration
@ConditionalOnWebApplication
@ConditionalOnClass({Servlet.class, DispatcherServlet.class, WebMvcConfigurerAdapter.class})
@ConditionalOnMissingBean({WebMvcConfigurationSupport.class})
@AutoConfigureOrder(-2147483638)
@AutoConfigureAfter({DispatcherServletAutoConfiguration.class, ValidationAutoConfiguration.class})
public class WebMvcAutoConfiguration {

    @Import({WebMvcAutoConfiguration.EnableWebMvcConfiguration.class})
    @EnableConfigurationProperties({WebMvcProperties.class, ResourceProperties.class})
    public static class WebMvcAutoConfigurationAdapter extends WebMvcConfigurerAdapter {

        @Bean
        @ConditionalOnBean({View.class})
        @ConditionalOnMissingBean
        public BeanNameViewResolver beanNameViewResolver() {
            BeanNameViewResolver resolver = new BeanNameViewResolver();
            resolver.setOrder(2147483637);
            return resolver;
        }
    }
}

咱们能够抽取到咱们自定义starter时一样须要的一些配置。程序员

@Configuration  //指定这个类是一个配置类
@ConditionalOnXXX  //指定条件成立的状况下自动配置类生效
@AutoConfigureOrder  //指定自动配置类的顺序
@Bean  //向容器中添加组件
@ConfigurationProperties  //结合相关xxxProperties来绑定相关的配置
@EnableConfigurationProperties  //让xxxProperties生效加入到容器中

自动配置类要能加载须要将自动配置类，配置在META-INF/spring.factories中
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
org.springframework.boot.autoconfigure.admin.SpringApplicationAdminJmxAutoConfiguration,\
org.springframework.boot.autoconfigure.aop.AopAutoConfiguration,\

模式

咱们参照 spring-boot-starter 咱们发现其中没有代码：github

咱们在看它的pom中的依赖中有个 springboot-starterweb

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

咱们再看看 spring-boot-starter 有个 spring-boot-autoconfigurespring

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

关于web的一些自动配置都写在了这里 ，因此咱们有总结：apache

启动器starter只是用来作依赖管理
须要专门写一个相似spring-boot-autoconfigure的配置模块
用的时候只须要引入启动器starter，就可使用自动配置了

命名规范

官方命名空间springboot

  • 前缀：spring-boot-starter-
  • 模式：spring-boot-starter-模块名
  • 举例：spring-boot-starter-web、spring-boot-starter-jdbc

自定义命名空间微信

  • 后缀：-spring-boot-starter
  • 模式：模块-spring-boot-starter
  • 举例：mybatis-spring-boot-starter

3、自定义starter实例

咱们须要先建立两个工程 hello-spring-boot-starter 和 hello-spring-boot-starter-autoconfigurermybatis

1. hello-spring-boot-starter

1.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.gf</groupId>
    <artifactId>hello-spring-boot-starter</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>hello-spring-boot-starter</name>

    <!-- 启动器 -->
    <dependencies>
        <!-- 引入自动配置模块 -->
        <dependency>
            <groupId>com.gf</groupId>
            <artifactId>hello-spring-boot-starter-autoconfigurer</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>
    </dependencies>


</project>

同时删除 启动类、resources下的文件，test文件。

2. hello-spring-boot-starter-autoconfigurer

1. 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.gf</groupId>
    <artifactId>hello-spring-boot-starter-autoconfigurer</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>hello-spring-boot-starter-autoconfigurer</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.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>
        <!-- 引入spring-boot-starter，全部starter的基本配合 -->
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
        </dependency>

    </dependencies>


</project>

2. HelloProperties

package com.gf.service;

import org.springframework.boot.context.properties.ConfigurationProperties;

@ConfigurationProperties(prefix = "gf.hello")
public class HelloProperties {

    private String prefix;
    private String suffix;

    public String getPrefix() {
        return prefix;
    }

    public void setPrefix(String prefix) {
        this.prefix = prefix;
    }

    public String getSuffix() {
        return suffix;
    }

    public void setSuffix(String suffix) {
        this.suffix = suffix;
    }

}

3. HelloService

package com.gf.service;


public class HelloService {

    HelloProperties helloProperties;

    public HelloProperties getHelloProperties() {
        return helloProperties;
    }

    public void setHelloProperties(HelloProperties helloProperties) {
        this.helloProperties = helloProperties;
    }

    public String sayHello(String name ) {
        return helloProperties.getPrefix()+ "-" + name + helloProperties.getSuffix();
    }
}

4. HelloServiceAutoConfiguration

package com.gf.service;

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

@Configuration
@ConditionalOnWebApplication //web应该生效
@EnableConfigurationProperties(HelloProperties.class)
public class HelloServiceAutoConfiguration {

    @Autowired
    HelloProperties helloProperties;

    @Bean
    public HelloService helloService() {
        HelloService service = new HelloService();
        service.setHelloProperties( helloProperties  );
        return service;
    }


}

5. spring.factories

在 resources 下建立文件夹 META-INF 并在 META-INF 下建立文件 spring.factories ，内容以下：

# Auto Configure
org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
com.gf.service.HelloServiceAutoConfiguration

到这儿，咱们的配置自定义的starter就写完了 ，咱们hello-spring-boot-starter-autoconfigurer、hello-spring-boot-starter 安装成本地jar包。

3、测试自定义starter

咱们建立个项目 hello-spring-boot-starter-test，来测试系咱们写的stater。

1. 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.gf</groupId>
    <artifactId>hello-spring-boot-starter-test</artifactId>
    <version>0.0.1-SNAPSHOT</version>
    <packaging>jar</packaging>

    <name>hello-spring-boot-starter-test</name>
    <description>Demo project for Spring Boot</description>

    <parent>
        <groupId>org.springframework.boot</groupId>
        <artifactId>spring-boot-starter-parent</artifactId>
        <version>1.5.9.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>

        <!-- 引入自定义starter -->
        <dependency>
            <groupId>com.gf</groupId>
            <artifactId>hello-spring-boot-starter</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

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

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


</project>

2. HelloController

package com.gf.controller;

import com.gf.service.HelloService;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.PathVariable;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class HelloController {

    @Autowired
    HelloService helloService;

    @GetMapping("/hello/{name}")
    public String hello(@PathVariable(value = "name") String name) {
        return helloService.sayHello( name + " , " );
    }

}

3. application.properties

gf.hello.prefix = hi
gf.hello.suffix = what's up man ?

我运行项目访问 http://127.0.0.1:8080/hello/zhangsan，结果以下：

hi-zhangsan , what's up man ?

源码下载: https://github.com/gf-huanchupk/SpringBootLearning

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