@Bean和@Autowaired区别

引言

今天在构建项目的时候引入redisUtils的时候发生了错误,错误如下

***************************
APPLICATION FAILED TO START
***************************

Description:

Field redisTemplateDB0 in net.cc.ucare.adsbhandler.config.RedisConfiguration required a single bean, but 2 were found:
    - redisTemplate: defined by method 'redisTemplate' in class path resource [net/cc/ucare/adsbhandler/config/RedisTemplateConfiguration.class]
    - stringRedisTemplate: defined by method 'stringRedisTemplate' in class path resource [net/cc/ucare/adsbhandler/config/RedisTemplateConfiguration.class]

Action:

Consider marking one of the beans as @Primary, updating the consumer to accept multiple beans, or using @Qualifier to identify the bean that should be consumed

大体意思是,你的这个对象在构建的时候应该是一个,但是却取到了两个,需要将这两个做标志一区分开,可以用@Primary或者@Qualifier注解进行区分.
我的代码如下,这是一个redis的配置类

@Configuration
public class RedisConfiguration {
    /**
     * redis 0号库
     */
    @Autowired
    // 这里是上面报错所说的DB0,通过看源码才知道这用的底层都是一样的,怪不得区分不开.
    private RedisTemplate redisTemplateDB0;
    @Autowired
    private StringRedisTemplate stringRedisTemplateDB0;
    /**
     * redis 1号库
     */
    @Autowired
    private RedisTemplate redisTemplateDB1;
    @Autowired
    private StringRedisTemplate stringRedisTemplateDB1;
    /**
     * redis 2号库
     */
    @Autowired
    private RedisTemplate redisTemplateDB2;
    @Autowired
    private StringRedisTemplate stringRedisTemplateDB2;
    /**
     * redis 3号库
     */
    @Autowired
    private RedisTemplate redisTemplateDB3;
    @Autowired
    private StringRedisTemplate stringRedisTemplateDB3;
    /**
     * redis 6号库
     */
    @Autowired
    private StringRedisTemplate stringRedisTemplateDB6;
    /**
     * redis 7号库
     */
    @Autowired
    private StringRedisTemplate stringRedisTemplateDB7;

    @Bean
    public RedisUtils redisUtils() {
        RedisUtils redisUtils = new RedisUtils();
        redisUtils.putRedisTemplate(RedisUtils.db0, null);
        redisUtils.putRedisTemplate(RedisUtils.db1, null);
        redisUtils.putRedisTemplate(RedisUtils.db2, null);
        redisUtils.putRedisTemplate(RedisUtils.db3, null);
        redisUtils.putRedisTemplate(RedisUtils.db6, null);
        redisUtils.putRedisTemplate(RedisUtils.db7, null);

        redisUtils.putStringRedisTemplate(RedisUtils.db0, stringRedisTemplateDB0);
        redisUtils.putStringRedisTemplate(RedisUtils.db1, stringRedisTemplateDB1);
        redisUtils.putStringRedisTemplate(RedisUtils.db2, stringRedisTemplateDB2);
        redisUtils.putStringRedisTemplate(RedisUtils.db3, stringRedisTemplateDB3);
        redisUtils.putStringRedisTemplate(RedisUtils.db6, stringRedisTemplateDB6);
        redisUtils.putStringRedisTemplate(RedisUtils.db7, stringRedisTemplateDB7);
        return redisUtils;
    }
}

解决

这里是上面报错所说的DB0,通过看源码才知道这用的底层都是一样的,怪不得区分不开.
这个是报错里的那个类的源码,然后他说加上的那两个注解就需要加在这里

@Configuration
@ConditionalOnClass(RedisOperations.class)
@EnableConfigurationProperties(RedisProperties.class)
@Import({ LettuceConnectionConfiguration.class, JedisConnectionConfiguration.class })
public class RedisAutoConfiguration {

    @Bean
    @ConditionalOnMissingBean(name = "redisTemplate")
    public RedisTemplate<Object, Object> redisTemplate(
            RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
        RedisTemplate<Object, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

    @Bean
    @ConditionalOnMissingBean
    public StringRedisTemplate stringRedisTemplate(
            RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
        StringRedisTemplate template = new StringRedisTemplate();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

}

重写后

加上@Override和@Primary注解,因为是Spring配置类,为了让其读到要加上@Configuration注解
加@Qualifier也可以,上网搜一下怎样用就行,需要将名字输入即可

@Configuration
public class RedisTemplateConfiguration extends RedisAutoConfiguration {

    @Override
    @Bean
    @Primary
    @ConditionalOnMissingBean(name = "redisTemplate")
    public RedisTemplate<Object, Object> redisTemplate(
            RedisConnectionFactory redisConnectionFactory) throws UnknownHostException {
        RedisTemplate<Object, Object> template = new RedisTemplate<>();
        template.setConnectionFactory(redisConnectionFactory);
        return template;
    }

}

重新运行应该就能成功了

@Bean和@Autowired的区别

@Bean告诉Spring: 这是我修饰的一个实例,请帮我保存着,我会随时过来拿
@Autowried告诉Spring: 麻烦给我我修饰的实例,就像刚才@Bean在你这创建的那种

@Autowried相当于隐藏了getset方法

@Bean相当于一个写好的构造方法,而@Autowired相当于get方法,哈哈

来自为知笔记(Wiz)