旅游路线收藏功能-分析、后台代码

分析

当页面加载完成后，发送ajax请求，获取用户是否收藏的标记

根据标记，展示不同的按钮样式

 

后台代码

RouteServlet类：

/**
     * 判断当前登录用户是否收藏过该线路
     */
    public void isFavorite(HttpServletRequest request, HttpServletResponse response){
        // 1.获取线路id
        String rid = request.getParameter("rid");
        // 2.获取当前登录用户 user
        User user =(User) request.getSession().getAttribute("user");
        // 用户id
        int uid;
        if (user == null){
            // 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,request);

FavoriteService接口：

public interface FavoriteService {
    /**
     * 判断是否收藏
     * @param rid
     * @param uid
     * @return
     */
    public boolean isFavorite(String rid,int uid);
}

FavoriteServiceImpl实现类：

    private FavoriteDao favoriteDao = new FavoriteDaoImpl();
    @Override
    public boolean isFavorite(String rid, int uid) {
        Favorite favorite = favoriteDao.findByRidAndUid(Integer.parseInt(rid), uid);

　　　　// 如果对象有值，则为true，反之则为false

　　　　return favorite != null; 
} }

FavoriteDao接口：

public interface FavoriteDao {

    /**
     * 根据rid和uid查询收藏信息
     * @param rid
     * @param uid
     * @return
     */
    public Favorite findByRidAndUid(int rid,int uid);
}

FavoriteDaoImpl实现类：

public class FavoriteDaoImpl implements FavoriteDao {
    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());

    @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.class), rid, uid);
        } catch (DataAccessException e) {
//            e.printStackTrace();
        }
        return favorite;
    }
}