struts2自动接收表单数据

提交页面主要代码：

<form method="post" action="messageAction">
   <input type="text" name="userName" value="userName Andy"/><br/>
   <input type="submit" value="提交"/> 
  </form>

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action类:

package action;
import org.apache.struts2.ServletActionContext;
import com.opensymphony.xwork2.ActionSupport;
public class MessageAction extends ActionSupport{;
    private String userName; //变量名要和表单的名字一样，这样才能自动接收表单数据
    private static final long serialVersionUID = 1L;

    //方法get和set不能少,不然会取不到表单数据。
    public String getUserName() {
        return userName;
    }
    public void setUserName(String userName) {
        this.userName = userName;
    }

    public String execute(){
        System.out.println("execute");
        System.out.println(userName);
        ServletActionContext.getRequest().setAttribute("info",userName);
        return SUCCESS;
    }
}