类别id传递
点击了不同的分类后将来看到的旅游线路不一样的。通过分析数据库表结构，发现
旅游线路表和分类表是一个多对一的关系
CategoryServiceImpl实现类：
public class CategoryServiceImpl implements CategoryService {
private CategoryDao categoryDao = new CategoryDaoImpl();
@Override
public List<Category> findAll() {
//1、从redis中查询
//获取jedis客户端
Jedis jedis = JedisUtil.getJedis();
//可以使用sortedset排序查询
// Set<String> categorys = jedis.zrange("category", 0, -1);
//1.3查询sortedset中的分数（cid）和值（cname）
Set<Tuple> categorys = jedis.zrangeWithScores("category", 0, -1);
List<Category> cs = null;
//2、判断查询的集合是否为空
if (categorys == null || categorys.size()==0){
System.out.println("从数据库查询.....");
//3、如果为空，需要从数据库查询，再将数据存入redis
//从数据库查询
cs = categoryDao.findAll();
//将数据集合存储到redis中，category的key
for (int i = 0; i < cs.size(); i++) {
jedis.zadd("category",cs.get(i).getCid(),cs.get(i).getCname());
}
}else {
System.out.println("从redis查询.....");
//4、如果不为空，直接返回
cs = new ArrayList<>();
for (Tuple tuple : categorys) {
Category category = new Category();
category.setCname(tuple.getElement());
category.setCid((int) tuple.getScore());
cs.add(category);
}
}
return cs;
}
}
header.html类：
<script>
$(function () {
$.get("user/findOne",{},function (data) {
var msg = "欢迎回来,"+data.name;
$("#span_username").html(msg);
});
$.get("category/findAll",{},function (data) {
var lis = '<li class="nav-active"><a href="index.html">首页</a></li>';
//遍历数组，拼接字符串
for (var i = 0; i < data.length; i++) {
var li = '<li><a href="route_list.html?cid='+data[i].cid+'">'+data[i].cname+'</a></li>';
lis+=li;
}
lis+='<li><a href="favoriterank.html">收藏排行榜</a></li>';
//将lis字符串，设置到ul的html内容中
$("#category").html(lis);
});
});
</script>
route_list.html页面：
<script>
$(function () {
var search = location.search;
//切割字符串，拿到第二个值
var id = search.split("=")[1];
alert(id)
});
</script>
分页数据展示分析
创建PageBean对象：
/**
* 分页对象
*/
public class PageBean<T> {
private int totalCount;//总记录数
private int totalPage;//总页数
private int currentPage;//当前页码
private int pageSize;//每页显示的条数
private List<T> list;//每页显示的数据集合
@Override
public String toString() {
return "PageBean{" +
"totalCount=" + totalCount +
", totalPage=" + totalPage +
", currentPage=" + currentPage +
", pageSize=" + pageSize +
", list=" + list +
'}';
}
public int getTotalCount() {
return totalCount;
}
public void setTotalCount(int totalCount) {
this.totalCount = totalCount;
}
public int getTotalPage() {
return totalPage;
}
public void setTotalPage(int totalPage) {
this.totalPage = totalPage;
}
public int getCurrentPage() {
return currentPage;
}
public void setCurrentPage(int currentPage) {
this.currentPage = currentPage;
}
public int getPageSize() {
return pageSize;
}
public void setPageSize(int pageSize) {
this.pageSize = pageSize;
}
public List<T> getList() {
return list;
}
public void setList(List<T> list) {
this.list = list;
}
}
RouteServlet类：
@WebServlet("/route/*")
public class RouteServlet extends BaseServlet {
private RouteService routeService = new RouteServiceImpl();
/**
* 分页查找
* @param request
* @param response
* @throws ServletException
* @throws IOException
*/
public void pageQuery(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
//接收参数
String currentPageStr = request.getParameter("currentPage");
String pageSizeStr = request.getParameter("pageSize");
String cidstr = request.getParameter("cid");
int cid = 0;
//2、处理参数
if (cidstr != null && cidstr.length()>0){
cid = Integer.parseInt(cidstr);
}
int currentPage = 0;//当前页码，如果不传递，则默认为第一页
if (currentPageStr!=null && currentPageStr.length()>0){
currentPage = Integer.parseInt(currentPageStr);
}else {
currentPage = 1;
}
int pageSize = 0;//每页显示条数，如果不传递，默认每页显示5条记录
if (pageSizeStr != null && pageSizeStr.length()==0){
pageSize = Integer.parseInt(pageSizeStr);
}else {
pageSize = 5;
}
//3、调用service查询pageBean对象
PageBean<Route> pb = routeService.pageQuery(cid, currentPage, pageSize);
//4、将pageBean对象序列化为json，返回
writeValue(pb,response);
}
}
RouteService接口：
/**
* 线路service
*/
public interface RouteService {
/**
* 根据类别进行分页查询
* @param cid
* @param currentPage
* @param pageSize
* @return
*/
public PageBean<Route> pageQuery(int cid,int currentPage,int pageSize);
}
RouteServiceIpl实现类：
public class RouteServiceImpl implements RouteService {
private RouteDao routeDao = new RouteDaoImpl();
@Override
public PageBean<Route> pageQuery(int cid, int currentPage, int pageSize) {
//封装PageBean
PageBean<Route> pb = new PageBean<>();
//设置当前页码
pb.setCurrentPage(currentPage);
//设置每页显示条数
pb.setPageSize(pageSize);
//设置总记录数
int totalCount = routeDao.findTotalCount(cid);
pb.setTotalCount(totalCount);
//设置当前页显示的数据集合
int start = (currentPage-1)*pageSize;
List<Route> list = routeDao.findByPage(cid, start, pageSize);
pb.setList(list);
//设置总页数 = 总记录数/每页显示条数
int totalPage = totalCount%pageSize==0 ? totalCount/pageSize : (totalCount/pageSize)+1;
pb.setTotalPage(totalPage);
return pb;
}
}
RouteDao接口：
public interface RouteDao {
/**
* 根据cid查询总记录数
*/
public int findTotalCount(int cid);
/**
* 根据cid，start，pageSize查询当前页的数据集合
*/
public List<Route> findByPage(int cid,int start,int pageSize);
}
RouteDaoImpl实现类：
public class RouteDaoImpl implements RouteDao {
private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());
@Override
public int findTotalCount(int cid) {
String sql = "select count(*) from tab_route where cid = ?";
return template.queryForObject(sql, Integer.class, cid);
}
@Override
public List<Route> findByPage(int cid, int start, int pageSize) {
String sql = "select * from tab_route where cid = ? limit ?,?";
return template.query(sql, new BeanPropertyRowMapper<>(Route.class), cid, start, pageSize);
}
}
标签：return,分页,pageSize,展示,int,cid,后台,currentPage,public From： https://www.cnblogs.com/xjw12345/p/16624033.html