SpringBoot学习(2)

自己开发一个spring boot starter的步骤
1.新建一个项目（全部都基于maven），比如新建一个spring-boot-starter-redis的maven项目

pom.xml:

<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.study.spring-boot</groupId>
    <artifactId>spring-boot-starter-redis</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

    <name>spring-boot-starter-redis</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencies>
        <dependency>
            <groupId>org.springframework.boot</groupId>
            <artifactId>spring-boot-starter</artifactId>
            <version>1.5.3.RELEASE</version>
        </dependency>
        <dependency>
            <groupId>redis.clients</groupId>
            <artifactId>jedis</artifactId>
            <version>2.9.0</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>3.8.1</version>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

2.需要一个配置类，配置类里面需要装配好需要提供出去的类

配置类：

package com.study.spring_boot_redis;

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

@ConfigurationProperties(prefix="redis")
public class RedisProperties {
    private String host;
    private Integer port;
    public String getHost() {
        return host;
    }
    public void setHost(String host) {
        this.host = host;
    }
    public Integer getPort() {
        return port;
    }
    public void setPort(Integer port) {
        this.port = port;
    }
}

package com.study.spring_boot_redis;


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

import redis.clients.jedis.Jedis;

@Configuration
@ConditionalOnClass(Jedis.class)
@EnableConfigurationProperties(RedisProperties.class)
public class RedisAutoConfiguration {
    @Bean
    @ConditionalOnMissingBean
    public Jedis Jedis(RedisProperties redisProperties) {
        return new Jedis(redisProperties.getHost(),redisProperties.getPort());
        
    }
}

3.
(1)使用@Enable，使用@Import导入需要装配的类

Enable注解：

package com.study.spring_boot_redis;

import java.lang.annotation.Documented;
import java.lang.annotation.ElementType;
import java.lang.annotation.Retention;
import java.lang.annotation.RetentionPolicy;
import java.lang.annotation.Target;

import org.springframework.context.annotation.Import;

@Target(ElementType.TYPE)
@Retention(RetentionPolicy.RUNTIME)
@Documented
@Import(RedisAutoConfiguration.class)
public @interface EnableRedis {
    
}

(2)/META-INF/spring.factories，在org.springframework.boot.autoconfigure.EnableAutoConfiguration配置需要装配的类

/spring-boot-starter-redis/src/main/resources/META-INF/spring.factories：

org.springframework.boot.autoconfigure.EnableAutoConfiguration = com.study.spring_boot_redis.RedisAutoConfiguration

真正的项目：springbootstarter（maven项目）

pom.xml:

<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.study.springboot</groupId>
    <artifactId>springboot</artifactId>
    <version>1.0.0</version>
    <packaging>jar</packaging>

    <name>springboot</name>
    <url>http://maven.apache.org</url>

    <properties>
        <project.build.sourceEncoding>UTF-8</project.build.sourceEncoding>
    </properties>

    <dependencyManagement>
        <dependencies>
            <dependency>
                <groupId>org.springframework.boot</groupId>
                <artifactId>spring-boot-dependencies</artifactId>
                <version>1.5.3.RELEASE</version>
                <scope>import</scope>
                <type>pom</type>
            </dependency>
        </dependencies>
    </dependencyManagement>

    <dependencies>
        <dependency>
            <groupId>com.study.spring-boot</groupId>
            <artifactId>spring-boot-starter-redis</artifactId>
            <version>1.0.0</version>
        </dependency>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <scope>test</scope>
        </dependency>
    </dependencies>
</project>

/springbootstarter/src/main/resources/application.properties:

redis.host=127.0.0.1
redis.port=6379

//@EnableRedis
@SpringBootApplication
public class App {

    public static void main(String[] args) {
        ConfigurableApplicationContext context = SpringApplication.run(App.class,args);
        Jedis jedis = context.getBean(Jedis.class);
        jedis.set("id", "root123");
        System.out.println(jedis.get("id"));
        context.close();
    }

}