求助！为什么前端jsp接收不到后端action传来的值？

Question

package com.admin;

import java.util.ArrayList;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpSession;
import org.apache.struts2.ServletActionContext;

import com.core.CalTime;
import com.opensymphony.xwork2.Action;

import db.link.ParkinfoDao;
import db.link.Parking_info;
import db.link.Parking_record;
import db.link.ParkreDao;
//import db.link.ParkreDao;
import db.link.Prinfo;
import db.link.User;
import db.link.UserDao;

public class LoginAction implements Action{

    private String username;
    private String password;
    private String type;
    private String tip;
    private ArrayList<User> list;
    public ArrayList<Parking_info> plist;
    public ArrayList<String> slist;//这是重点！
    public ArrayList<Parking_record> prlist;
    public int a[][];//这是重点！
    public ArrayList<Double> fare;//这是重点！
    //public ArrayList<Prinfo> prlist=new ArrayList<Prinfo>();
    private UserDao userdao=new UserDao();
    private ParkinfoDao pdao=new ParkinfoDao();
    private ParkreDao rdao=new ParkreDao();

    public LoginAction(){

    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    public String getType() {
        return type;
    }

    public void setType(String type) {
        this.type = type;
    }

    public String getTip() {
        return tip;
    }

    public void setTip(String tip) {
        this.tip = tip;
    }

    public String execute(){
        list=userdao.getUserList();
        plist=pdao.getPrList();
        slist=rdao.getCarNum();
        /*for(int i=0;i<plist.size();i++){
            prlist.add(new Prinfo());
            prlist.get(i).setId(plist.get(i).getId());
            prlist.get(i).setStatus(plist.get(i).getStatus());
            prlist.get(i).setPlicense(plist.get(i).getId());
        }*/
        prlist=rdao.getPrList();
        CalTime clt=new CalTime();

        ArrayList<Integer> il=new ArrayList<Integer>();
        fare=new ArrayList<Double>();

        for(int i=0;i<prlist.size();i++){
            Parking_record pr=prlist.get(i);
            if(pr.getFare()==0){
                fare.add(clt.getNowFare(pr.getIntime()));
            }
        }

        a=new int[fare.size()][3];
        int j=0;
        for(int i=0;i<prlist.size();i++){
            Parking_record pr=prlist.get(i);
            if(pr.getDuration()==0){
                il=clt.getShowTime(pr.getIntime());
                a[j][0]=il.get(0);
                a[j][1]=il.get(1);
                a[j][2]=il.get(2);
                j++;
            }
        }
        User user;
        for(int i=0;i<list.size();i++){
            user=list.get(i);
            if(user.getUsername().equals(username)&&user.getPassword().equals(password)){
                if(user.getType().equals(type)){
                    HttpServletRequest request=ServletActionContext.getRequest();
                    HttpSession session=request.getSession();
                    session.setAttribute("username", username);
                    session.setAttribute("plist", plist);
                    session.setAttribute("prlist", prlist);
                    System.out.println(fare.get(0)+":"+slist.get(1));
                    if(type.equals("operator")){
                        return SUCCESS;
                    }
                    else{
                        return LOGIN;
                    }
                }
                else{
                    setTip("用户与类型不匹配");
                    return ERROR;
                }
            }
        }
        setUsername("USERNAME");
        setPassword("Password");
        setTip("用户或密码错误,请重新输入");
        return ERROR;
    }
}

以上是后台的代码

<div class="content" id="print" style="display:none">
        <!--<font size="3">车牌号码：</font> <input type="text"></input> <input
            type="submit" value="登记"></input>-->
        <input type="text" value="输入关键字">
        <s:form>
        <table style="width: 60%;margin:auto">
        <tr>
        <th>编号</th>
        <th>车牌号码</th>
        <th>所在车位</th>
        <th>入场时间</th>
        <th>出场时间</th>
        <th>停车时长</th>
        <th>总费用</th>
        </tr>
        <s:iterator value="prlist" status="sts" id="prl" begin="0" end="8"> 
        <tr>
        <td><s:property value="#prl.id"/></td>
        <td><s:property value="#prl.plate_license"/></td>
        <td><s:property value="#prl.parking_num"/></td>
        <td><s:property value="#prl.intime"/></td>
        <td><s:if test="#prl.outtime == null ">未离场</s:if>
        <s:else><s:property value="#prl.outtime"/></s:else>
        <td><s:if test="#prl.duration == 0">
        <s:property value="time[<%=j%>][0]"/>天
        <s:property value="time[<%=j%>][1]"/>小时
        <s:property value="time[<%=j%>][2]"/>分钟
        <% j++; %>
        </s:if>
        <s:else><s:property value="#prl.duration"/></s:else>
        <td><s:property value="fare[0]"/>
        <s:else><s:property value="#prl.fare"/></s:else></td>
        </tr>
        </s:iterator>
        </table>
        </s:form>
    </div>

    <div class="content" id="abnormal" style="display:none">
        <!--<font size="3">车牌号码：</font> <input type="text"></input> <input
            type="submit" value="登记"></input>
            <input type="text" value="输入车位号码"> -->
        <input type="text" name="word" placeholder="请输入车位号码"/>
        <input type="submit"  value="Search" /><br/>
        <s:form>
        <table style="width: 60%;margin:auto">
        <tr>
        <th>车位号码</th>
        <th>车位状态</th>
        <th>车牌号码</th>
        <th>状态修改</th>
        </tr>
        <s:iterator value="plist" status="st" id="list" begin="0" end="8"> 
        <tr>
        <td><s:property value="#list.id"/></td>
        <td><s:if test="#list.status == 'idle' ">空闲</s:if>
        <s:elseif test="#list.status == 'assigned' ">已分配</s:elseif>
        <s:else>异常</s:else></td>
        <td><s:if test="slist[#st.index] == null ">无车辆</s:if>
        <s:else><s:property value="slist[#st.index]"/></s:else></td>
        <td><a href="http://www.w3school.com.cn/" target="_blank">修改</a></td>
        </tr>
        </s:iterator>
        </table>
        </s:form>
    </div>

以上是前台的代码

就是很奇怪，数组slist的值可以接收到，并且正常使用。然而数组fare的值却接收不到，页面上对应的fare一栏全是空的。我很疑惑，为什么会这样，有大佬能为我解答吗？

Answer 1

其实是页面缓存了，没有更新的问题……实际上代码没有错误，迭代器成功读到了session的内容……尴尬了……尴尬