如何只为所有控制器和页面绑定一次共享片段的数据?

使用 HandlerInterceptor .

public class CategoryListAddInterceptor extends HandlerInterceptorAdapter {

    @Autowired
    private CategoryDao categoryDao; //for example

    @Override
    public void postHandle(HttpServletRequest request,
                           HttpServletResponse response,
                           Object handler,
                           ModelAndView modelAndView) throws Exception {

        modelAndView.getModel().put("categoryList", categoryDao.getPostCategoryList());
    }        
}

在配置XML文件中,添加:

<mvc:interceptors>
    <mvc:interceptor>
        <mvc:mapping path="/**"/>
        <mvc:exclude-mapping path="/demo/**"/> <!-- can add exclude patterns if needed -->
        <bean class="package.name.CategoryListAddInterceptor"/>
    </mvc:interceptor>
</mvc:interceptors>

更新:

正如你所得到的 NullPointerException 在呼叫时 modelAndView.getModel() 你可以这样做来实现同样的事情:

@Override
public void postHandle(HttpServletRequest request,
                       HttpServletResponse response,
                       Object handler,
                       ModelAndView modelAndView) throws Exception {

    request.setAttribute("categoryList", categoryDao.getPostCategoryList());
}