SpringBoot自定义@EnableXX

在springboot框架中，有很多类似于@EnableXX的注解，比如@EnableAsync，@EnableScheduling等等，一个简单的注解即可实现功能相应功能的引入，这么神奇吗？那我们该怎么自定义@Enable注解，来使用这些骚操作呢？

发现规律

随便拿几个注解看看：

是否发现，其实@Enable注解都有一个@Import注解包含其中，而@Import注解类似于xml配置中的标签，起到引入Bean的目的，这样一来，@Enable注解的规律就找到了，接下来就是自定义注解的时刻...

@EableRedis自定义

• 自定义注解

import org.springframework.context.annotation.Import;
import java.lang.annotation.*;

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

• 编写配置类RedisConfigure.java

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.boot.context.properties.EnableConfigurationProperties;
import org.springframework.context.annotation.Bean;
import org.springframework.data.redis.connection.RedisPassword;
import org.springframework.data.redis.connection.RedisStandaloneConfiguration;
import org.springframework.data.redis.connection.jedis.JedisClientConfiguration;
import org.springframework.data.redis.connection.jedis.JedisConnectionFactory;
import org.springframework.data.redis.core.RedisTemplate;
import org.springframework.data.redis.serializer.GenericJackson2JsonRedisSerializer;
import org.springframework.data.redis.serializer.StringRedisSerializer;
import redis.clients.jedis.JedisPoolConfig;

import java.time.Duration;

/**
 * @author wangkun
 */
@EnableConfigurationProperties(RedisConfig.class)
public class RedisConfigure {
    @Autowired
    private RedisConfig redisConfig;

    /**
     * 连接池配置信息
     */
    @Bean
    public JedisPoolConfig jedisPoolConfig() {
        JedisPoolConfig jedisPoolConfig = new JedisPoolConfig();
        // 最大连接数
        jedisPoolConfig.setMaxTotal(redisConfig.getMaxActive());
        // 当池内没有可用连接时，最大等待时间
        jedisPoolConfig.setMaxWaitMillis(redisConfig.getMaxWaitMillis());
        // 最大空闲连接数
        jedisPoolConfig.setMinIdle(redisConfig.getMaxIdle());
        // 最小空闲连接数
        jedisPoolConfig.setMinIdle(redisConfig.getMinIdle());
        // 其他属性可以自行添加
        return jedisPoolConfig;
    }

    /**
     * Jedis 连接
     * @param jedisPoolConfig
     * @return
     */
    @Bean
    public JedisConnectionFactory jedisConnectionFactory(JedisPoolConfig jedisPoolConfig) {
        JedisClientConfiguration jedisClientConfiguration = JedisClientConfiguration.builder().usePooling()
                .poolConfig(jedisPoolConfig).and().readTimeout(Duration.ofMillis(redisConfig.getTimeout())).build();
        RedisStandaloneConfiguration redisStandaloneConfiguration = new RedisStandaloneConfiguration();
        redisStandaloneConfiguration.setHostName(redisConfig.getHost());
        redisStandaloneConfiguration.setPort(redisConfig.getPort());
        redisStandaloneConfiguration.setPassword(RedisPassword.of(redisConfig.getPassword()));
        redisStandaloneConfiguration.setDatabase(redisConfig.getDatabase());
        return new JedisConnectionFactory(redisStandaloneConfiguration, jedisClientConfiguration);
    }

    @Bean
    public RedisTemplate<String, Object> redisTemplate() {
        RedisTemplate<String, Object> redisTemplate = new RedisTemplate<>();
        redisTemplate.setKeySerializer(new StringRedisSerializer());
        redisTemplate.setValueSerializer(new StringRedisSerializer());
        redisTemplate.setHashKeySerializer(new StringRedisSerializer());
        redisTemplate.setHashValueSerializer(new GenericJackson2JsonRedisSerializer());
        redisTemplate.setConnectionFactory(jedisConnectionFactory(jedisPoolConfig()));
        return redisTemplate;
    }
}

• 配置类RedisConfig.java

import lombok.Data;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.boot.context.properties.ConfigurationProperties;
import org.springframework.context.annotation.Configuration;

@ConfigurationProperties(prefix = "redis.common")
@Data
public class RedisConfig {
    private int database;
    private String host;
    private int port;
    private String password;
    private int timeout;
    private int maxActive;
    private long maxWaitMillis;
    private int maxIdle;
    private int minIdle;
}

@EnableRedis的使用

• 启动类

import com.antelope.gate.common.redis.EnableRedis;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.boot.autoconfigure.jdbc.DataSourceAutoConfiguration;

/**
 * @author Aissue
 */
@SpringBootApplication(exclude = DataSourceAutoConfiguration.class)
@EnableRedis
public class GapServerApplication {
    public static void main(String[] args) {
        SpringApplication springApplication = new SpringApplication(GapServerApplication.class);
        springApplication.run(args);
    }

}

• 配置属性

# redis config
redis.common.host=127.0.0.1
redis.common.database=0
redis.common.port=6379
redis.common.password=
redis.common.timeout=300000
redis.common.max-active=10
redis.common.max-idle=8
redis.common.max-wait=-1
redis.common.min-idle=0
redis.common.cidToGBId=CID-GBID

小结

其实@EnableXX的自定义注解还是比较简单的，如果做到举一反三，一定可以让自己的代码灵活而优雅。