问题

项目中使用了@ComponentScan注解，但是idea中 basePackages 指定的包路径一直报红，看了下basePackages是个数组，于是乎好奇起来，basePackages = {}是填String数组还是填用逗号隔开的String呢？

@ComponentScan(basePackages = {"com.aaa.aaa,com.bbb.bbb"}

放码过来

Spring 启动执行代码

org.springframework.context.annotation.ComponentScanAnnotationParser#parse

        Set<String> basePackages = new LinkedHashSet<>();
        String[] basePackagesArray = componentScan.getStringArray("basePackages");
        for (String pkg : basePackagesArray) {
            String[] tokenized = StringUtils.tokenizeToStringArray(this.environment.resolvePlaceholders(pkg),
                    ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS);
            Collections.addAll(basePackages, tokenized);
        }

强行翻译：
在单个String字符串中，多个上下文配置路径之间的 这些字符",; \t\n"中的任意一个 都会被认为是分隔符

ConfigurableApplicationContext.CONFIG_LOCATION_DELIMITERS

    /**
     * Any number of these characters are considered delimiters between
     * multiple context config paths in a single String value.
     * @see org.springframework.context.support.AbstractXmlApplicationContext#setConfigLocation
     * @see org.springframework.web.context.ContextLoader#CONFIG_LOCATION_PARAM
     * @see org.springframework.web.servlet.FrameworkServlet#setContextConfigLocation
     */
    String CONFIG_LOCATION_DELIMITERS = ",; \t\n";

结论

@ComponentScan(basePackages = {})填String数组 或者 用逗号隔开的String 都可以；为了idea显示兼容一点，我还是该成了 String数组

参考

@ComponentScan源码分析