springBoot 工具类掉service层方法

原始错误代码，报错空指针异常，Debug显示zyService为null：

public class WordUtil
{
    @Autowired
    private IZyService zyService;
 
	public XXX getXxx(){
		List List1 = zyService.selectXxxList();
	}
}

修改后代码：

@Component
public class WordUtil
{
    @Autowired
    private IZyService zyService;

    public static WordUtil wordUtil;

    // 必须要有这个无参构造函数，否则会报错
    public WordUtil() { }

    @PostConstruct
    public void init() {
        wordUtil = this;
    }
    
    // 调用service层的方法
	public XXX getXxx(){
		List List1 = wordUtil.zyService.selectXxxList();
	}
}

没写无参构造函数时，会报错Consider defining a bean of type ‘java.lang.String’ in your configuration