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
9.2BaseServlet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();
}
}
}
9.3UserServlet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
register.html
login.html
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>¥</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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