struts2与jsp传值.md

title: Struts2 action和jsp之间传值

layout: post

date: 2017-03-20 12:57:50

categories: java web

tags: [jsp, struts2]

---

struts2 action 向 jsp 传值

1. action中定义一个成员变量，对它提供get/set方法，在jsp中通过标签或EL表达式取值

//action 示例
@Action("handleMessage")
public class HandleMessage extends ActionSupport{
  private String message;
  public String getMessage(){
    return message;
  }
  public void setMessage(String message){
    this.message=message;
  }
}
//jsp页面取值
 ${message} 或者 <s:property value="message"> 

2. 在action中用HttpServletRequest,HttpSession,ServletContext对象进行值的存取

   //action 示例
   @Action("handleMessage")
   public class HandleMessage extends ActionSupport{
     //get HttpServletRequest 
     Map<String,Object> request = (Map) actionContext.get("request"); 
     request.put("a", "a is in request"); 
   
     //get HttpSession 
     Map<String,Object> session = actionContext.getSession(); 
     session.put("b", "b is in session"); 
   
     //get ServletContext 
     Map<String,Object> application  = actionContext.getApplication(); 
     application.put("c", "c is in application");
   }
   //jsp页面取值
   ${a} ${b} ${c}
   or
   ${requestScope.a} ${sessionScopse.b} ${applicationScope.c}
   or 
   <% 
      String a=(String)request.getAttribute("a");
      String b=(String)session.getAttribute("b");
      String c=(String)application.getAttribute("c");
   %>

3. jsp显示值还可以用struts2标签 参考链接

jsp 向 struts2 action 传值

1. url传值

   jsp中直接在url中加入被传递的参数

   如：<%=basePath%>handleMessage?message=aa

2. form表单传值

3. session,request,application传值

4. ajax传值

5. 后台接收

   1. action中设置属性message并写出相应的get/set方法就可以获得值
   2. request.getParameter("message")

6. 注意点

   • url传值后，转到的页面url为带参数的，如果刷新会重复提交请求。

     解决方案 ：在struts配置中将action result的type属性设为“redirect"