04、SpringBoot自动配置-自定义starter

步骤分析：#

需求：自定义redis-starter。要求当导入redis坐标时，SpringBoot自动创建Jedis的Bean。

步骤：

①创建 redis-spring-boot-autoconfigure 模块

②创建 redis-spring-boot-starter 模块,依赖 redis-spring-boot-autoconfigure的模块

③在 redis-spring-boot-autoconfigure 模块中初始化 Jedis 的 Bean。并定义META-INF/spring.factories 文件

④在测试模块中引入自定义的 redis-starter 依赖，测试获取 Jedis 的Bean，操作 redis。

创建redis-spring-boot-starter工程：#

该工程仅用来聚合redis-spring-boot-autoconfigure工程pom文件中引入redis-spring-boot-autoconfigure坐标：

        <!--引入configure-->
        <dependency>
            <groupId>com.itheima</groupId>
            <artifactId>redis-spring-boot-autoconfigure</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency> 

创建redis-spring-boot-autoconfigure配置工程：#

创建RedisProperties配置文件参数绑定类：

package com.itheima.redis.config;

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

@ConfigurationProperties(prefix = "redis")
public class RedisProperties {

    private String host = "localhost";
    private int port = 6379;

    public String getHost() {
        return host;
    }

    public void setHost(String host) {
        this.host = host;
    }

    public int getPort() {
        return port;
    }

    public void setPort(int port) {
        this.port = port;
    }
}

创建RedisAutoConfiguration自动配置类：

package com.itheima.redis.config;

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
@EnableConfigurationProperties(RedisProperties.class)
@ConditionalOnClass(Jedis.class)
public class RedisAutoConfiguration {
    /**
     * 提供Jedis的bean
     */
    @Bean
    @ConditionalOnMissingBean(name = "jedis")
    public Jedis jedis(RedisProperties redisProperties) {
        System.out.println("RedisAutoConfiguration....");
        return new Jedis(redisProperties.getHost(), redisProperties.getPort());
    }
}

在resource目录下创建META-INF文件夹并创建spring.factories：

org.springframework.boot.autoconfigure.EnableAutoConfiguration=\
  com.itheima.redis.config.RedisAutoConfiguration

在springboot-enable工程中引入自定义的redis的starter：

        <!--自定义的redis的starter-->
        <dependency>
            <groupId>com.itheima</groupId>
            <artifactId>redis-spring-boot-starter</artifactId>
            <version>0.0.1-SNAPSHOT</version>
        </dependency>

测试：

        Jedis jedis = context.getBean(Jedis.class);
        System.out.println(jedis);