7-Dark Horse Travel Net-Tourist Route Collection

Tourist route collection function

analysis

Determine whether the currently logged-in user has favorited the line

When the page is loaded, send an ajax request to get the user ’s favorite
tags. Show different button styles according to the tags

Code behind

RouteServlet

public void isFavorite(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
    //1. 获取线路id
    String rid = request.getParameter("rid");

    //2. 获取当前登录的用户 user
    User user = (User) request.getSession().getAttribute("user");
    int uid;//用户id
    if(user == null){
        //用户尚未登录
        uid = 0;
    }else{
        //用户已经登录
        uid = user.getUid();
    }

    //3. 调用FavoriteService查询是否收藏
    boolean flag = favoriteService.isFavorite(rid, uid);

    //4. 写回客户端
    writeValue(flag,response);
}

FavoriteService

@Override
public boolean isFavorite(String rid, int uid) {

    Favorite favorite = favoriteDao.findByRidAndUid(Integer.parseInt(rid), uid);

    return favorite != null;//如果对象有值，则为true，反之，则为false
}

Favorite→

@Override
public Favorite findByRidAndUid(int rid, int uid) {
    Favorite favorite = null;
    try {
        String sql = " select * from tab_favorite where rid = ? and uid = ?";
        favorite = template.queryForObject(sql, new BeanPropertyRowMapper<Favorite>(Favorite.class), rid, uid);
    } catch (DataAccessException e) {
        e.printStackTrace();
    }
    return favorite;
}

Foreground code

route_detail.html

$(function () {
   // 发送请求，判断用户是否收藏过该线路
    var rid = getParameter("rid");
    $.get("route/isFavorite",{rid:rid},function (flag) {
        if(flag){
            // 用户已经收藏过
            //<a  class="btn already" disabled="disabled">
            //设置收藏按钮的样式
            $("#favorite").addClass("already");
            $("#favorite").prop("disabled",disabled);



        }else{
            // 用户没有收藏
        }
    });

Dynamic display of collections

//设置收藏次数
$("#favoriteCount").html("已收藏"+route.count+"次");

Backstage

RouteService

//4. 查询收藏次数
int count = favoriteDao.findCountByRid(route.getRid());
route.setCount(count);

Favorite→

@Override
public int findCountByRid(int rid) {
    String sql = "SELECT COUNT(*) FROM tab_favorite WHERE rid = ?";

    return template.queryForObject(sql,Integer.class,rid);
}