//在UserController中验证码展示
public void valid(HttpServletRequest request,HttpServletResponse response) throws IOException {
    ValidateCode vc = new ValidateCode(120, 50, 1, 5);
    System.out.println("验证码:"+vc.getCode());
    request.getSession().setAttribute("imgCode",vc.getCode());
    vc.write(response.getOutputStream());
}

//3.验证输入的验证码 是否正确
$("#vcode").change(function(){
    $.get("/user","action=checkCode&code="+this.value,function(data){
        if(data==0){
            $("#checkMsg").html("<font color='green'>OK</font>");
            $("#btn").removeAttr("disabled");
        }else{
            $("#checkMsg").html("<font color='red'>ERROR</font>");
            $("#btn").prop("disabled",true); //设置disable属性
        }
    })
});

//验证码校验
public String checkCode(HttpServletRequest request,HttpServletResponse response){
    String code = request.getParameter("code");  //获取表单子控件验证码值
    //获取验证码图片的内容
    String imgCode = (String) request.getSession().getAttribute("imgCode");
    if(code.equalsIgnoreCase(imgCode)){
        return "0";  //0代表验证成功
    }else{
        return "1";  //1代表验证失败
    }
}

//2.点击验证码 跟新验证码
$("#pagecode").click(function(){
    $("#pagecode").attr("src","/user?action=valid&c=?"+Math.random());
});

//记录登录账户：
String auto = request.getParameter("auto");
Cookie cookie = new Cookie(ConstUtils.UPASS,username+"-"+password);
if(auto!=null){ //不为null，则说明勾选了；为null则去掉勾选
    cookie.setMaxAge(60*60*24*14);  //单位秒  14天
}else{
    cookie.setMaxAge(0);  //清除cookie
}
response.addCookie(cookie);

//注销session与cookie
public String logOut(HttpServletRequest request,HttpServletResponse response){
    //移除session
    request.getSession().removeAttribute(ConstUtils.LOGIN);

    //清除cookie
    Cookie cookie = new Cookie(ConstUtils.UPASS,"xxx");
    cookie.setMaxAge(0);  //立马失效
    response.addCookie(cookie);
    return ConstUtils.RED+"/index.jsp";
}

$.ajax({
    url:"${pageContext.request.contextPath}/type?action=show",
    type:"GET",
    //dataType:"json", //返回json字符串后，进行json解析成对象
    success:function(data){
        data= JSON.parse(data);  //解析成对象
        for(var i in data){
            var a = $("<a href='${pageContext.request.contextPath}/getGoodsListByTypeId?typeid="+data[i].t_id+"'>"+data[i].t_name+"</a>");
            $("#goodsType").append(a);
        }
    },
    error:function(){
        alert("失败");
    }
})

@WebServlet("/type")
public class TypeController extends BaseServlet {
    private TypeService typeService = new TypeServiceImpl();
    public String show(HttpServletRequest request, HttpServletResponse response){
        List<Type> list = typeService.showAll();  //查询类别
        //将对象解析成json数据,回传出去
        return new Gson().toJson(list);
    }
}

//header.jsp中发请求
var a = $("<a href='${pageContext.request.contextPath}/goods?action=show&tid="+data[i].t_id+"'>"+data[i].t_name+"</a>");

@WebServlet("/goods")
public class ProductController extends BaseServlet {
    private GoodsService goodsService = new GoodsServiceImpl();
    public String show(HttpServletRequest request,HttpServletResponse response){
        System.out.println("产品展示");
        //获取tid参数
        int tid = Integer.parseInt(request.getParameter("tid"));
        //再调用业务层,返回集合
        List<Product> list = goodsService.showByTid(tid);
        //产品展示完成，进行转发
        request.setAttribute("glist",list);
        return ConstUtils.FOR +"/goodsList.jsp";
    }
}

@Override //分页具体实现
public List<Product> selectByPage(int startIndex, int pageSize,int tid) throws SQLException {
    String sql = "select * from product where t_id=? limit ?,?";
    return runner.query(sql,new BeanListHandler<>(Product.class),tid,startIndex,pageSize);
}

public Page<Product> getPage(int tid, String current) {
    int currentPage = 1;
    int pageSize = 4;
    if(current!=null){
        currentPage = Integer.parseInt(current);  //当前页赋值
    }
    Page<Product> page = new Page<>(currentPage,pageSize);
    try {
        long totalCount = goodsDao.getTotalCount(tid);  //dao层获取总条数
        page.setTotalCount(totalCount); //设置总条数
        long pageCount = (totalCount%pageSize==0)?totalCount/pageSize:totalCount/pageSize+1;
        page.setPageCount(pageCount);   //设置总页数
        int startIndex = (currentPage-1)*pageSize; //求起始行
        //设置内容
        page.setList(goodsDao.selectByPage(startIndex,pageSize,tid));
    }catch (Exception e){
        e.printStackTrace();
    }
    return page;
}

//在控制层，返回分页信息
public String show(HttpServletRequest request,HttpServletResponse response){
    System.out.println("产品展示");
    //获取tid参数
    int tid = Integer.parseInt(request.getParameter("tid"));
    String current = request.getParameter("currentPage");
    Page<Product> page = goodsService.getPage(tid, current);

    //存储分页信息
    request.setAttribute("p",page);
    return ConstUtils.FOR +"/goodsList.jsp";
}

//展示单个商品详情
public String goodsDetail(HttpServletRequest request,HttpServletResponse response){
    //获取参数信息
    int pid = Integer.parseInt(request.getParameter("pid"));
    Product product = goodsService.showByPid(pid);  //根据pid，获取唯一信息
    request.setAttribute("goods",product);
    return ConstUtils.FOR+"/goodsDetail.jsp";
}

@Data
@NoArgsConstructor
@AllArgsConstructor
public class Cart {
  private int c_id;  //购物车ID
  private int u_id;  //用户ID
  private int p_id;  //商品ID
  private BigDecimal c_count;  //商品小计
  private int c_num;  //商品数量
}

import java.util.List;

public class ProductPage {
    private int currentPage;        // 当前页码
    private int pageSize;           // 每页显示的记录数
    private int totalRecords;       // 总记录数
    private int totalPages;         // 总页数
    private List<Product> productList; // 当前页的商品列表

    // 构造函数
    public ProductPage(int currentPage, int pageSize, int totalRecords, List<Product> productList) {
        this.currentPage = currentPage;
        this.pageSize = pageSize;
        this.totalRecords = totalRecords;
        this.productList = productList;

        // 计算总页数
        this.totalPages = (int) Math.ceil((double) totalRecords / pageSize);
    }

    // Getter 和 Setter 方法
    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 int getTotalRecords() {
        return totalRecords;
    }

    public void setTotalRecords(int totalRecords) {
        this.totalRecords = totalRecords;
    }

    public int getTotalPages() {
        return totalPages;
    }

    public void setTotalPages(int totalPages) {
        this.totalPages = totalPages;
    }

    public List<Product> getProductList() {
        return productList;
    }

    public void setProductList(List<Product> productList) {
        this.productList = productList;
    }
}