struts中action如何接收地址栏里的参数

看你是使用的struts1还是Struts2
Struts1的话 可以通过request对象获取 也就是
String param=request.getParameter("param");
Struts2的话 先在Action中定义参数变量 并提供相应的get和set方法
public class TestAction {
private String param;
public String getParam() {
return param;
}

public void setParam(String param) {
this.param= param;
}
}

public ActionForward main(ActionMapping mapping, ActionForm form, HttpServletRequest request, HttpServletResponse response) throws Exception {
String lang = (String) request.getSession().getAttribute("lang");
......................................

http://127.0.0.1:8080/help/user/login.action?username=www
String username = ServletActionContext.getRequest().getAttribute("username");