Struts2里使用paramsPrepareParamsStack的问题

Question

Struts2版本: 2.3.16.3
struts.xml中配置的拦截器:

 <default-interceptor-ref name="paramsPrepareParamsStack" />

Action:

public class SignonAction extends ActionSupport implements Preparable, ModelDriven<DynamicBean> {
    DynamicBean bean = null;
    String beanCode = null;

    public String getBeanCode() {
        return beanCode;
    }

    public void setBeanCode(String beanCode) {
        this.beanCode = beanCode;
    }

    public DynamicBean getBean() {
        return bean;
    }

    public void setBean(DynamicBean bean) {
        this.bean = bean;
    }

    public String execute() {
        System.out.println("execute(): " + beanCode);
        return SUCCESS;
    }

    @Action("save")
    public String save() {
        System.out.println("save(): " + beanCode);
        return "fail";
    }

    @Override
    public void prepare(){
        System.out.println("prepare(): " + beanCode);
        if(beanCode!=null)
            bean = (new ClassBuilder()).getDynamicBean(beanCode);
    }

    @Override
    public DynamicBean getModel() {
        return bean;
    }
} 

前台访问signon.action?beanCode=Person,后台运行结果为:
prepare(): null
execute(): Person

按理说paramsPrepareParamsStack应该先调用params, 再调用prepare, 但为什么在prepare方法里会取不到beanCode的值, 但是在execute里又可以取到呢?

Answer 1

找到原因了,拦截器不生效是由于使用了struts的convention插件.两个解决办法:
1. 在action上添加拦截器注释
2. 在action上添加parentPackage注释, 指向struts里的package name, 这个时候struts里定义的默认拦截器才会生效.