static类型autowired 注入失败

Posted 2020-10-19 zhouyeqin

原代码：注入commonService对象失败

　　@Autowired
    private static CommonService commonService;public static List<Map<String, Object>> getCode(String codeType,  boolean allOption ,String orderType){
        return commonUtil.commonService.getCode(codeType, allOption, orderType);
    }

commonService在static状态下不能够被依赖注入,会抛出运行时异常java.lang.NullPointerException,为什么呢?
静态变量/类变量不是对象的属性,而是一个类的属性,spring则是基于对象层面上的依赖注入. 

解决方式1：

　　@Autowired
    private CommonService commonService;
    private static CommonUtil commonUtil;
    
    @PostConstruct
    public void init() {
        commonUtil = this;
        commonUtil.commonService = this.commonService;
    }
    
    public static List<Map<String, Object>> getCode(String codeType,  boolean allOption ,String orderType){
        return commonUtil.commonService.getCode(codeType, allOption, orderType);
    }