JAVAEE中用Session简单实现购物车功能示例代码

session简单实现购物车功能

这个小程序主要就3个页面，一个商品列表页面(homeservlet)，一个是提示加入购物车页面(addcarttipservlet)，一个是显示购物车清单页面(showcartservlet)。

homeservlet页面：

@webservlet({ "/homeservlet", "/home" })
public class homeservlet extends httpservlet {
  private static final long serialversionuid = 1l;

  public homeservlet() {
    super();
  }

  protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {

    request.setcharacterencoding("utf-8");
    response.setcontenttype("text/html;charset=utf-8");
    printwriter out = response.getwriter();
    out.print("<h2>书单</h2><hr/><br/>");
    out.print("人类简史<a href='"+request.getcontextpath()+"/addcarttip?id=1'>加入购物车</a><br/>");
    out.print("未来简史<a href='"+request.getcontextpath()+"/addcarttip?id=2'>加入购物车</a><br/>");
    out.print("世界简史<a href='"+request.getcontextpath()+"/addcarttip?id=3'>加入购物车</a><br/>");
    out.print("时间简史<a href='"+request.getcontextpath()+"/addcarttip?id=4'>加入购物车</a><br/>");
    out.print("<a href='"+request.getcontextpath()+"/show/cart'>查看购物车</a><br/>");
  }

  protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
    doget(request, response);
  }

}

addcarttipservlet页面：

@webservlet({ "/addcarttipsservlet", "/addcarttip" })
public class addcarttipsservlet extends httpservlet {
  private static final long serialversionuid = 1l;


  public addcarttipsservlet() {
    super();
  }

  protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {

    request.setcharacterencoding("utf-8");
    response.setcontenttype("text/html;charset=utf-8");

    httpsession session = request.getsession();
    list<string> list = (list<string>) session.getattribute("cart");
    if(list==null){
      list=new arraylist<>();
    }

    string id = request.getparameter("id");
    list.add(id);
    session.setattribute("cart", list);

    system.out.println(list.tostring());
    response.getwriter().println("已加入购物车<br/>"
        + "<a href='"+request.getcontextpath()+"/home'>继续购物</a><br/>"
        + "<a href='"+request.getcontextpath()+"/show/cart'>查看购物车</a><br/>");
  }

  protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
    doget(request, response);
  }

}

showcartsevlet页面

@webservlet({ "/showcartservlet", "/show/cart" })
public class showcartservlet extends httpservlet {
  private static final long serialversionuid = 1l;

  public showcartservlet() {
    super();
  }


  protected void doget(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
    request.setcharacterencoding("utf-8");
    response.setcontenttype("text/html;charset=utf-8");
    printwriter out = response.getwriter();
    list<string> list = (list<string>)request.getsession().getattribute("cart");
    if(list!=null){   
      out.print("你的购物清单：<br/>");
      for (string string : list) {
        out.println(dbutils.findbyid(string)+"<br/>");
      }
      out.println("<br/><a href='"+request.getcontextpath()+"/home'>继续购物</a><br/>");
    }else{
      out.println("你还没有将商品添加到购物车<br/>"
          + "<a href='"+request.getcontextpath()+"/home'>返回商品列表</a><br/>");
    }
  }

  protected void dopost(httpservletrequest request, httpservletresponse response) throws servletexception, ioexception {
    doget(request, response);
  }

}

dbutils：存储着商品信息

public class dbutils {
  private static map<string,string> map = new hashmap<>();

  static{
    map.put("1", "人类简史");
    map.put("2", "未来简史");
    map.put("3", "世界简史");
    map.put("4", "时间简史");
  }

  public static string findbyid(string id){
    return map.get(id);
  }

}

以上就是本文的全部内容，希望对大家的学习有所帮助，也希望大家多多支持。