Question

我一直在练习spring mvc，但在显示数据时遇到了问题。运行视图时，它根本不显示任何数据。这不是数据库连接的问题，因为登录工作正常。

home.jsp

<html>
<head>
<!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <script type="text/javascript"
            src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.1/jquery.min.js"></script>
    <script type="text/javascript"></script>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>Store</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" >
<style>

.container{
    display:flex;
    justfy-content: center;
}
</style>
</head>
<body>
<div class="jumbotron">
            <div class="container text-center">
                <h1>THE STORE</h1>      
            </div>
        </div>

    <div class="container-fluid bg-3 text-center">
        <h2>Featured Products</h2>
        <div class="row">
            <c:forEach var="item" items="${items}">
                <div class="col-sm-3">
                    <p> ${item.name}  </p>
                </div>
                <br>
            </c:forEach>


        </div>
    </div>






</body>
</html>

ItemController

package com.jj.controller;

import java.util.List;

import javax.servlet.http.HttpServletRequest;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Controller;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.servlet.ModelAndView;

import com.jj.model.Item;
import com.jj.service.ItemService;

@Controller
public class ItemController {

    @Autowired
    private ItemService itemService;



    @RequestMapping(value = {"/home"}, method= RequestMethod.POST)
    public ModelAndView showItems(ModelAndView model, HttpServletRequest request) {



         List<Item> items = itemService.findAllItems();


         model.addObject("items", items);
         model.setViewName("home.jsp");

        return model;
    }




}

ItemService

package com.jj.service;

import java.sql.Connection;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;
import java.util.List;
import java.util.logging.Logger;

import org.springframework.stereotype.Service;

import com.jj.db.DBPool;
import com.jj.model.Item;

@Service
public class ItemService {

    private static Logger logger = Logger.getLogger(ItemService.class.getName());

    //final static Logger logger = (Logger) LogManager.getLogger(ItemService.class);


    public List<Item> findAllItems(){

        logger.info("attempting to find all items");

        ArrayList<Item> items = new ArrayList<Item>();

        String sql = "SELECT * FROM " + Item.TABLE_NAME;
        Connection conn = null;
        DBPool.getInstance();
        conn = DBPool.getConnection();
        PreparedStatement pstmt = null;
        ResultSet rs = null;

        try {
            pstmt = conn.prepareStatement(sql);
            rs = pstmt.executeQuery();
            while(rs.next()) {
                Item i = new Item();
                i.setId(rs.getInt(Item.COLUMN_IDITEMS));
                i.setName(rs.getString(Item.COLUMN_NAME));

                items.add(i);
            }
        } catch (SQLException e) {
            // TODO Auto-generated catch block
            e.printStackTrace();
        } finally {
            try {
                pstmt.close();
                rs.close();
            } catch (SQLException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }

        }
        logger.info("items " + items);

        return items;
    }

}

我一直在练习spring mvc，但在显示数据时遇到了问题。运行视图时，它根本不显示任何数据。这不是数据库连接的问题，因为登录工作正常。

Answer 1

您需要taglib。我在下面附加了代码：

<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<html>
<head>
<!-- Required meta tags -->
    <meta charset="utf-8">
    <meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
    <script type="text/javascript"
            src="http://ajax.googleapis.com/ajax/libs/jquery/1.4.1/jquery.min.js"></script>
    <script type="text/javascript"></script>
<!-- Required meta tags -->
<meta charset="utf-8">
<meta name="viewport" content="width=device-width, initial-scale=1, shrink-to-fit=no">
<title>Store</title>
<link rel="stylesheet" href="https://stackpath.bootstrapcdn.com/bootstrap/4.3.1/css/bootstrap.min.css" >
<style>

.container{
    display:flex;
    justfy-content: center;
}
</style>
</head>
<body>
<div class="jumbotron">
            <div class="container text-center">
                <h1>THE STORE</h1>      
            </div>
        </div>
    <div class="container-fluid bg-3 text-center">
        <h2>Featured Products</h2>
        <div class="row">
            <c:forEach var="item" items="${items}">
                <div class="col-sm-3">
                    <p> ${item.name}  </p>
                </div>
                <br>
            </c:forEach>
        </div>
    </div>
</body>
</html>

用于Spring Boot的配置JSP，您可以找到：example

使用spring

1 个答案: