Spring MVC使用jstl 標籤c:forEach 遍歷輸出雙層巢狀List的資料方式
阿新 • • 發佈：2021-08-17
目錄
- Spring MVC tl 標籤c:forEach 遍歷輸出雙層巢狀List資料
- 1、建立Controller
- 2、建立對應的jsp頁面
- 注意事項：
- springMVC的forEach不能正常顯示
- 1、問題
- 2、解決
Spring MVC jstl 標籤c:forEach 遍歷輸出雙層巢狀List資料
具體操作步驟如下：
1、建立Controller
import .util.ArrayList; import java.util.List; import javax.servlet.http.HttpServletRequest; import javax.servlet.http.HttpServletResponse; import org.springframework.stereotype.Controller; import org.springframework.ui.Model; import org.springframework.web.bind.annotation.RequestMapping; import com.mahaochen.springmvc.domain.Goods; import com.mahaochen.springmvc.domain.Inventory; @Controller @RequestMapping("/shop") public class ShoppingController { @RequestMapping("/shoppingCart") public String getShoppingCart(HttpServletRequest request,HttpServletResponse response,Model model){ model.addAttribute("list",generateData()); return "shoppingCart"; } private List<Inventory> generateData(){ List<Inventory> inventories = new ArrayList<Inventory>(); for(int i=0 ; i<2 ; i++){ switch (i) { case 0: Inventory inventory1 = new Inventory(); inventory1.setInventoryType("水果"); List<Goods> goodsList1 = new ArrayList<Goods>(); for(int j=0;j<5;j++){ Goods goods = new Goods(); goods.setGoodsName("蘋果"+j); goodsList1.add(goods); } inventory1.setGoodList(goodsList1); inventories.add(inventory1); break; default: Inventory inventory2 = new Inventory(); inventory2.setInventoryType("蔬菜"); List<Goods> goodsList2 = new ArrayList<Goods>(); for(int j=0;j<5;j++){ Goods goods = new Goods(); goods.setGoodsName("茄子"+j); goodsList2.add(goods); } inventory2.setGoodList(goodsList2); inventories.add(inventory2); break; } } return inventories; } }
2、建立對應的jsp頁面
<%@ page language="java" contentType="text/html; charset=UTF-8" pageEncoding="UTF-8"%> <%@taglib prefix="c" uri="http://java.sun.com/jsp/jstl/core" %> <!DOCTYPE html PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN" "http://www.w3.org/TR/html4/loose.dtd"> <html> <head> <meta http-equiv="Content-Type" content="text/html; charset=UTF-8"> <title>購物車</title> </head> <body> <c:forEach items="${list }" var="item"> ${item.inventoryType}<br /> <c:set value="${item.goodList }" var="subItem"/> <c:forEach items="${subItem }" var="var"> --${var.goodsName }<br /> </c:forEach> </c:forEach> </body> </html>
注意事項：
JSTL1CYwCSq.1的庫 在JSP2.0(Servlet 2.4)及以後(推薦用JSTL1.1及以上)用：
<%@taglibprefix="c" uri="http://java.sun.com/jsp/jstl/core"%>
web.xml
<?xml version="1.0" encoding="UTF-8"?>
<web-app version="2.4"
xmlns="http://java.sun.com/xml/ns/j2ee"
xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
xsi:schemaLocation="http://java.sun.com/xml/ns/j2ee http://java.sun.com/xml/ns/j2ee/web-app_2_4.xsd" >
</web-app>
在 Servlet2.3及以前，
<%@taglibprefix="c" uri="http://java.sun.com/jstl/core"%>
與2.4比較，以後版本路徑少了jsp。
web.xml
<?xml version="1.0" encoding="UTF-8"?> <!DOCTYPE web-app PUBLIC "-//Sun Microsystems,Inc.//DTD Web Application 2.3//EN" "http://java.sun.com/dtd/web-app_2_3.dtd"> <web-app> </web-app>
不然會出現以下錯誤：
org.apache.jasper.JasperException:/WEB-INF/jsp/shoppingCart.jsp(line: 10,column: 1) According to TLD or attribute directive in tag file,attribute items does not accept any expressions
springMVC的forEach不能正常顯示
1、問題
在進行sprihttp://www.cppcns.comngMVC的forEach聯絡時,出現如下錯誤
org.客棧apache.jasper.JasperException: An exception occurred processing JSP page /WEB-INF/jsp/index.jsp at line 12
<table border="2" bgcolor="aqua" width="500px" >
<c:forEach items="${list}" var="student">
<tr >
<td height="50px">${student.id}</td>
<td height="50px">${student.name}</td>
</tr>
</c:forEach>
2、解決
forEach的獲取是通過getter來進行的，在實體類中新增getter方法即可。
以上為個人經驗，希望能給大家一個參考，也希望大家多多支援我們。