java day50【综合案例day02】

2022-09-26 07:51:43

由 java day49【综合案例day01】步骤：

9. 优化Servlet

9.1 目的

减少Servlet的数量，现在是一个功能一个Servlet，将其优化为一个模块一个Servlet，

相当于在数据库中一张表对应一个Servlet，在Servlet中提供不同的方法，完成用户的请求。

Idea控制台中文乱码解决：-Dfile.encoding=gb2312

9.2 BaseServlet编写：

public class BaseServlet extends HttpServlet {



    @Override

    protected void service(HttpServletRequest req, HttpServletResponse resp) throws ServletException, IOException {

        //System.out.println("baseServlet的service方法被执行了...");


        //完成方法分发

        //1.获取请求路径

        String uri = req.getRequestURI(); //   /travel/user/add

        System.out.println("请求uri:"+uri);//  /travel/user/add

        //2.获取方法名称

        String methodName = uri.substring(uri.lastIndexOf('/') + 1);

        System.out.println("方法名称："+methodName);

        //3.获取方法对象Method

        //谁调用我？我代表谁

        System.out.println(this);//UserServlet的对象cn.itcast.travel.web.servlet.UserServlet@4903d97e

        try {

            //获取方法

            Method method = this.getClass().getMethod(methodName, HttpServletRequest.class, HttpServletResponse.class);

            //4.执行方法

            //暴力反射

            //method.setAccessible(true);

            method.invoke(this,req,resp);

        } catch (NoSuchMethodException e) {

            e.printStackTrace();

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        } catch (InvocationTargetException e) {

            e.printStackTrace();

        }

    }

}

9.3 UserServlet改写

将之前的Servlet实现的功能，抽取到UserServlet中的不同方法中实现，并且将UserService创建抽取到成员变量位置

@WebServlet("/user/*") // /user/add /user/find
public class UserServlet extends BaseServlet {

    //声明UserService业务对象
    private UserService service = new UserServiceImpl();

    /**
     * 注册功能
     * @param request
     * @param response
     * @throws ServletException
     * @throws IOException
     */
    public void regist(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //验证校验
        String check = request.getParameter("check");
        //从sesion中获取验证码
        HttpSession session = request.getSession();
        String checkcode_server = (String) session.getAttribute("CHECKCODE_SERVER");
        session.removeAttribute("CHECKCODE_SERVER");//为了保证验证码只能使用一次
        //比较
        if(checkcode_server == null || !checkcode_server.equalsIgnoreCase(check)){
            //验证码错误
            ResultInfo info = new ResultInfo();
            //注册失败
            info.setFlag(false);
            info.setErrorMsg("验证码错误");
            //将info对象序列化为json
            ObjectMapper mapper = new ObjectMapper();
            String json = mapper.writeValueAsString(info);
            response.setContentType("application/json;charset=utf-8");
            response.getWriter().write(json);

     return;

        }


        //1.获取数据

        Map<String, String[]> map = request.getParameterMap();


        //2.封装对象

        User user = new User();

        try {

            BeanUtils.populate(user,map);

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        } catch (InvocationTargetException e) {

            e.printStackTrace();

        }


        //3.调用service完成注册

        //UserService service = new UserServiceImpl();

        boolean flag = service.regist(user);

        ResultInfo info = new ResultInfo();

        //4.响应结果

        if(flag){

            //注册成功

            info.setFlag(true);

        }else{

            //注册失败

            info.setFlag(false);

            info.setErrorMsg("注册失败!");

        }


        //将info对象序列化为json

        ObjectMapper mapper = new ObjectMapper();

        String json = mapper.writeValueAsString(info);


        //将json数据写回客户端

        //设置content-type

        response.setContentType("application/json;charset=utf-8");

        response.getWriter().write(json);


    }


    /**

     * 登录功能

     * @param request

     * @param response

     * @throws ServletException

     * @throws IOException

     */

    public void login(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.获取用户名和密码数据

        Map<String, String[]> map = request.getParameterMap();

        //2.封装User对象

        User user = new User();

        try {

            BeanUtils.populate(user,map);

        } catch (IllegalAccessException e) {

            e.printStackTrace();

        } catch (InvocationTargetException e) {

            e.printStackTrace();

        }


        //3.调用Service查询

       // UserService service = new UserServiceImpl();

        User u  = service.login(user);


        ResultInfo info = new ResultInfo();


        //4.判断用户对象是否为null

        if(u == null){

            //用户名密码或错误

            info.setFlag(false);

            info.setErrorMsg("用户名密码或错误");

        }

        //5.判断用户是否激活

        if(u != null && !"Y".equals(u.getStatus())){

            //用户尚未激活

            info.setFlag(false);

            info.setErrorMsg("您尚未激活，请激活");

        }

        //6.判断登录成功

        if(u != null && "Y".equals(u.getStatus())){

            request.getSession().setAttribute("user",u);//登录成功标记


            //登录成功

            info.setFlag(true);

        }


        //响应数据

        ObjectMapper mapper = new ObjectMapper();


        response.setContentType("application/json;charset=utf-8");

        mapper.writeValue(response.getOutputStream(),info);

    }


    /**

     * 查询单个对象

     * @param request

     * @param response

     * @throws ServletException

     * @throws IOException

     */

    public void findOne(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //从session中获取登录用户

        Object user = request.getSession().getAttribute("user");

        //将user写回客户端


        ObjectMapper mapper = new ObjectMapper();

        response.setContentType("application/json;charset=utf-8");

        mapper.writeValue(response.getOutputStream(),user);

    }


    /**

     * 退出功能

     * @param request

     * @param response

     * @throws ServletException

     * @throws IOException

     */

    public void exit(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.销毁session

        request.getSession().invalidate();


        //2.跳转登录页面

        response.sendRedirect(request.getContextPath()+"/login.html");

    }


    /**

     * 激活功能

     * @param request

     * @param response

     * @throws ServletException

     * @throws IOException

     */

    public void active(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.获取激活码

        String code = request.getParameter("code");

        if(code != null){

            //2.调用service完成激活

            //UserService service = new UserServiceImpl();

            boolean flag = service.active(code);


            //3.判断标记

            String msg = null;

            if(flag){

                //激活成功

                msg = "激活成功，请<a href='login.html'>登录</a>";

            }else{

                //激活失败

                msg = "激活失败，请联系管理员!";

            }

            response.setContentType("text/html;charset=utf-8");

            response.getWriter().write(msg);

        }

    }

}

9.4 页面路径改写

header.html

UserServiceImpl发送邮件

10. 分类数据展示

10.1 效果：

10.2 分析：

10.3 代码实现：

10.3.1 后台代码

CategoryServlet

@WebServlet("/category/*")
public class CategoryServlet extends BaseServlet {


    private CategoryService service = new CategoryServiceImpl();


    /**

     * 查询所有

     * @param request

     * @param response

     * @throws ServletException

     * @throws IOException

     */

    public void findAll(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.调用service查询所有

        List<Category> cs = service.findAll();

        //2.序列化json返回

       /* ObjectMapper mapper = new ObjectMapper();

        response.setContentType("application/json;charset=utf-8");

        mapper.writeValue(response.getOutputStream(),cs);*/

       writeValue(cs,response);


    }


}

CategoryService

public class CategoryServiceImpl implements CategoryService {


    private CategoryDao categoryDao = new CategoryDaoImpl();


    @Override

    public List<Category> findAll() {

        return categoryDao.findAll();

    }

}

CategoryDao

public class CategoryDaoImpl implements CategoryDao {


    private JdbcTemplate template = new JdbcTemplate(JDBCUtils.getDataSource());


    @Override

    public List<Category> findAll() {

        String sql = "select * from tab_category ";

        return template.query(sql,new BeanPropertyRowMapper<Category>(Category.class));

    }

}

在BaseServlet中封装了序列化json的方法

/**

 * 直接将传入的对象序列化为json，并且写回客户端

 * @param obj

 */
public void writeValue(Object obj,HttpServletResponse response) throws IOException {

    ObjectMapper mapper = new ObjectMapper();

    response.setContentType("application/json;charset=utf-8");

    mapper.writeValue(response.getOutputStream(),obj);

}


/**

 * 将传入的对象序列化为json，返回

 * @param obj

 * @return

 */
public String writeValueAsString(Object obj) throws JsonProcessingException {

    ObjectMapper mapper = new ObjectMapper();

    return mapper.writeValueAsString(obj);

}

10.3.2 前台代码

hader.html加载后，发送ajax请求，请求category/findAll

//查询分类数据

 $.get("category/findAll",{},function (data) {

     //[{cid:1,cname:国内游},{},{}]

     var lis = '<li class="nav-active"><a href="index.html">首页</a></li>';

     //遍历数组,拼接字符串(<li>)

     for (var i = 0; i < data.length; i++) {

         var li = '<li><a href="route_list.html">'+data[i].cname+'</a></li>';


         lis += li;

         

     }

     //拼接收藏排行榜的li,<li><a href="favoriterank.html">收藏排行榜</a></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);

 });

10.4 对分类数据进行缓存优化

分析发现，分类的数据在每一次页面加载后都会重新请求数据库来加载，对数据库的压力比较大，

而且分类的数据不会经常产生变化，所有可以使用redis来缓存这个数据。

分析：

10.5 优化代码实现

期望数据中存储的顺序就是将来展示的顺序，使用redis的sortedset

@Override
public List<Category> findAll() {

    //1.从redis中查询

    //1.1获取jedis客户端

    Jedis jedis = JedisUtil.getJedis();

    //1.2可使用sortedset排序查询

    Set<String> categorys = jedis.zrange("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,在将数据存入redis

        //3.1 从数据库查询

        cs = categoryDao.findAll();

        //3.2 将集合数据存储到redis中的 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中查询.....");


        //4.如果不为空,将set的数据存入list

        cs = new ArrayList<Category>();

        for (String name : categorys) {

            Category category = new Category();

            category.setCname(name);

            cs.add(category);


        }

    }



    return cs;

}

11. 旅游线路的分页展示

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时一个多对一的关系

查询不同分类的旅游线路sql

Select * from tab_route where cid = ?;

11.1 类别id的传递

Redis中查询score（cid）

public class CategoryServiceImpl implements CategoryService {


    private CategoryDao categoryDao = new CategoryDaoImpl();


    @Override

    public List<Category> findAll() {

        //1.从redis中查询

        //1.1获取jedis客户端

        Jedis jedis = JedisUtil.getJedis();

        //1.2可使用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,在将数据存入redis

            //3.1 从数据库查询

            cs = categoryDao.findAll();

            //3.2 将集合数据存储到redis中的 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中查询.....");


            //4.如果不为空,将set的数据存入list

            cs = new ArrayList<Category>();

            for (Tuple tuple : categorys) {

                Category category = new Category();

                category.setCname(tuple.getElement());

                category.setCid((int)tuple.getScore());

                cs.add(category);


            }

        }



        return cs;

    }

}

页面传递cid

header.html传递cid

var li = '<li><a href="route_list.html?cid='+data[i].cid+'">'+data[i].cname+'</a></li>';

获取cid

$(function () {

   var search = location.search;

   //alert(search);//?id=5

    // 切割字符串，拿到第二个值

    var cid = search.split("=")[1];

});

11.2 根据id查询不同类别的旅游线路数据

分页展示旅游线路数据：

11.2.1 分析

11.2.2 编码

1.客户端代码编写

$(function () {

    var search = location.search;

        // 切割字符串，拿到第二个值

    var cid = search.split("=")[1];


    //当页码加载完成后，调用load方法，发送ajax请求加载数据

    load(cid);

});

function load(cid ,currentPage){

    //发送ajax请求，请求route/pageQuery,传递cid

    $.get("route/pageQuery",{cid:cid,currentPage:currentPage},function (pb) {

        //解析pagebean数据，展示到页面上


        //1.分页工具条数据展示

        //1.1 展示总页码和总记录数

        $("#totalPage").html(pb.totalPage);

        $("#totalCount").html(pb.totalCount);


                var lis = "";


        var fristPage = '<li onclick="javascipt:load('+cid+')"><a href="javascript:void(0)">首页</a></li>';


        //计算上一页的页码

        var beforeNum =  pb.currentPage - 1;

        if(beforeNum <= 0){

            beforeNum = 1;

        }


        var beforePage = '<li  onclick="javascipt:load('+cid+','+beforeNum+')" class="threeword"><a href="javascript:void(0)">上一页</a></li>';


        lis += fristPage;

        lis += beforePage;

        //1.2 展示分页页码

        /*

            1.一共展示10个页码，能够达到前5后4的效果

            2.如果前边不够5个，后边补齐10个

            3.如果后边不足4个，前边补齐10个

        */


        // 定义开始位置begin,结束位置 end

        var begin; // 开始位置

        var end ; //  结束位置



        //1.要显示10个页码

        if(pb.totalPage < 10){

            //总页码不够10页


            begin = 1;

            end = pb.totalPage;

        }else{

            //总页码超过10页


            begin = pb.currentPage - 5 ;

            end = pb.currentPage + 4 ;


            //2.如果前边不够5个，后边补齐10个

            if(begin < 1){

                begin = 1;

                end = begin + 9;

            }


            //3.如果后边不足4个，前边补齐10个

            if(end > pb.totalPage){

                end = pb.totalPage;

                begin = end - 9 ;

            }

        }



        for (var i = begin; i <= end ; i++) {

            var li;

            //判断当前页码是否等于i

            if(pb.currentPage == i){


                li = '<li class="curPage" onclick="javascipt:load('+cid+','+i+')"><a href="javascript:void(0)">'+i+'</a></li>';


            }else{

                //创建页码的li

                li = '<li onclick="javascipt:load('+cid+','+i+')"><a href="javascript:void(0)">'+i+'</a></li>';

            }

            //拼接字符串

            lis += li;

        }






             var lastPage = '<li class="threeword"><a href="javascript:;">末页</a></li>';

        var nextPage = '<li class="threeword"><a href="javascript:;">下一页</a></li>';


        lis += nextPage;

        lis += lastPage;



        //将lis内容设置到 ul

        $("#pageNum").html(lis);




        

        //2.列表数据展示

        var route_lis = "";


        for (var i = 0; i < pb.list.length; i++) {

            //获取{rid:1,rname:"xxx"}

            var route = pb.list[i];


            var li = '<li>\n' +

                '                        <div class="img"><img src="'+route.rimage+'" style="width: 299px;"></div>\n' +

                '                        <div class="text1">\n' +

                '                            <p>'+route.rname+'</p>\n' +

                '                            <br/>\n' +

                '                            <p>'+route.routeIntroduce+'</p>\n' +

                '                        </div>\n' +

                '                        <div class="price">\n' +

                '                            <p class="price_num">\n' +

                '                                <span>&yen;</span>\n' +

                '                                <span>'+route.price+'</span>\n' +

                '                                <span>起</span>\n' +

                '                            </p>\n' +

                '                            <p><a href="route_detail.html">查看详情</a></p>\n' +

                '                        </div>\n' +

                '                    </li>';

            route_lis += li;

        }

        $("#route").html(route_lis);


        //定位到页面顶部

        window.scrollTo(0,0);

    });


}

2.服务器端代码编写

a) 创建PageBean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


    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;

    }

}

b) RouteServlet

@WebServlet("/route/*")
public class RouteServlet extends BaseServlet {


    private RouteService routeService = new RouteServiceImpl();


    /**

     * 分页查询

     * @param request

     * @param response

     * @throws ServletException

     * @throws IOException

     */

    public void pageQuery(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {

        //1.接受参数

        String currentPageStr = request.getParameter("currentPage");

        String pageSizeStr = request.getParameter("pageSize");

        String cidStr = request.getParameter("cid");


        int cid = 0;//类别id

        //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);


    }


}

c) RouteService

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<Route>();

        //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;//开始的记录数

        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;

    }

}

d) RouteDao

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>(Route.class),cid,start,pageSize);

    }

}

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