需求是在mybatis拦截器中注入RedisUtils用来缓存一些信息。

拦截器

@Component
@Intercepts({
        @Signature(type = Executor.class, method = "update", args = {MappedStatement.class, Object.class})
})
public class MybatisInterceptor implements Interceptor {

    private static final String CONFIG_KEY = "config";

    private static Map<String, Map<String, Config>> configMap;

    @Autowired
    private RedisUtils redisUtils;

    @PostConstruct
    public void init() {
        initializeMap();
    }

    private synchronized void initializeMap() {
        String ConfigStr = redisUtils.getValue(CONFIG_KEY);
    }

    @Override
    public Object intercept(Invocation invocation) throws Throwable {
        String ConfigStr = redisUtils.getValue(CONFIG_KEY);
        ...
    }

    ...
}

 配置类

@Configuration
@AutoConfigureAfter({PageHelperAutoConfiguration.class})
public class MybatisInterceptorConfig {
    @Autowired
    private List<SqlSessionFactory> sqlSessionFactoryList;

    public MybatisInterceptorConfig() {
    }

    @PostConstruct
    public void addMyInterceptor() {
        MybatisInterceptor mybatisInterceptor = new MybatisInterceptor();
        Iterator iterator = this.sqlSessionFactoryList.iterator();
        while(iterator .hasNext()) {
            SqlSessionFactory sqlSessionFactory = (SqlSessionFactory)var2.next();
            sqlSessionFactory.getConfiguration().addInterceptor(mybatisInterceptor);
        }

    }
}

调试时发现在mybatis拦截器定义的注解@PostConstruct方法中RedisUtils依赖已经注入，但是在拦截器的Intercept方法中redisUtils为null。

在配置类中将MybatisInterceptor改成@Bean注入后，Intercept执行时依赖问题解决

@Configuration
@AutoConfigureAfter({PageHelperAutoConfiguration.class})
public class MybatisInterceptorConfig {
    @Autowired
    private List<SqlSessionFactory> sqlSessionFactoryList;

    @Bean
    public MybatisInterceptor mybatisInterceptor() {
        return new MybatisInterceptor();
    }

    @PostConstruct
    public void addMyInterceptor() {
        MybatisInterceptor mybatisInterceptor = mybatisInterceptor();
        Iterator iterator = this.sqlSessionFactoryList.iterator();
        while(iterator .hasNext()) {
            SqlSessionFactory sqlSessionFactory = (SqlSessionFactory)var2.next();
            sqlSessionFactory.getConfiguration().addInterceptor(mybatisInterceptor);
        }

    }
}

其原因个人推测是通过@Component注入虽然可以将依赖注入到spring中，但是SqlSessionFactory.getConfiguration()中的拦截器是通过new设置的，在执行@PostConstruct初始化方法时用的时spring中注入的MybatisInterceptor，而在执行Intercept拦截时用的时new出的实例方法。因此将配置类中的MybatisInterceptor bean设置到SqlSessionFactory中即可。