struts2實現CRUD(增 刪 改 查)
阿新 • • 發佈：2018-12-14
CRUD是Create（建立）、Read（讀取）、Update（更新）和Delete（刪除）
首先，肯定是要與資料互動的，所以我們先寫一個bean類
程式碼如下：
public class Food { private Integer id; private String name; private Double price; public Integer getId() { return id; } public void setId(Integer id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public Double getPrice() { return price; } public void setPrice(Double price) { this.price = price; } public Food(Integer id, String name, Double price) { super(); this.id = id; this.name = name; this.price = price; } public Food() { super(); // TODO Auto-generated constructor stub } @Override public String toString() { return "Food [id=" + id + ", name=" + name + ", price=" + price + "]"; } }
在bean類中建立的欄位，與資料庫中的欄位相對應，
下面是Dao程式碼：
Dao介面：
public interface FoodDaoI {
//列表展示
List<Food> showFoodList();
//刪除操作
void delFoodById(Integer id);
//新增操作
void addFood(Food food);
//更新前回顯
Food findById(Integer id);
//更新
void updateFood(Food food);
}Dao實現類：
public class FoodDaoImpl implements FoodDaoI{ private QueryRunner qr=new QueryRunner(JDBCUtils3.getDataSource()); public List<Food> showFoodList() { String sql="select * from ee"; List<Food> list=null; try { list=qr.query(sql, new BeanListHandler<Food>(Food.class)); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return list; } public void delFoodById(Integer id) { String sql="delete from ee where id=?"; try { qr.update(sql, id); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public void addFood(Food food) { String sql="insert into ee set id=?,name=?,price=?"; try { qr.update(sql, food.getId(),food.getName(),food.getPrice()); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } public Food findById(Integer id) { String sql="select * from ee where id=?"; Food food=null; try { food=qr.query(sql, new BeanHandler<Food>(Food.class),id); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } return food; } public void updateFood(Food food) { String sql="update ee set name=?, price=? where id=?"; try { qr.update(sql, food.getName(),food.getPrice(),food.getId()); } catch (SQLException e) { // TODO Auto-generated catch block e.printStackTrace(); } } }
然後是action類，程式碼如下：
public class FoodAction extends ActionSupport implements ModelDriven<Food>{ private FoodDaoI foodDao=new FoodDaoImpl(); private static final long serialVersionUID = 5418396635382987020L; private List<Food> list; private Food food=new Food(); //列表展示 public String list() { list = foodDao.showFoodList(); return "list"; } //刪除操作 public String delete() { foodDao.delFoodById(food.getId()); return "delete"; } //新增操作 public String add() { foodDao.addFood(food); return "add"; } //更新前回顯 public String toupdate() { food=foodDao.findById(food.getId()); ServletActionContext.getRequest().setAttribute("food", food); return "toupdate"; } //更新操作 public String update() { foodDao.updateFood(food); return "update"; } //***************************************** public FoodDaoI getFoodDao() { return foodDao; } public void setFoodDao(FoodDaoI foodDao) { this.foodDao = foodDao; } public List<Food> getList() { return list; } public void setList(List<Food> list) { this.list = list; } public Food getFood() { return food; } public void setFood(Food food) { this.food = food; } public Food getModel() { // TODO Auto-generated method stub return food; } }
需要注意的是，本例子在action中實現了ModelDriven<>類，所以需要設定action類中，相應的getter/setter方法
接下來是struts.xml檔案的配置：
<?xml version="1.0" encoding="UTF-8" ?>
<!DOCTYPE struts PUBLIC
"-//Apache Software Foundation//DTD Struts Configuration 2.3//EN"
"http://struts.apache.org/dtds/struts-2.3.dtd">
<struts>
<package name="Struts2_CRUD_DEMO" extends="struts-default" namespace="/">
<action name="action_*" class="com.baidu.action.FoodAction" method="{1}" >
<result name="list" >/list.jsp</result>
<result name="delete" type="redirect">action_list</result>
<result name="add" type="redirect">action_list</result>
<result name="toupdate">/update.jsp</result>
<result name="update" type="redirect">action_list</result>
</action>
</package>
</struts>在strutsxml檔案中需要注意的是方法之間重定向的時候需要設定<result>標籤中的type屬性
下面是jsp：
列表展示jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
function del(id) {
location.href="action_delete?id="+id;
}
function toUpdate(id) {
location.href="action_toupdate?id="+id;
}
</script>
</head>
<body>
<h2>Food List</h2>
<table border="1" style="align-content: center;">
<tr>
<td>id</td>
<td>name</td>
<td>price</td>
</tr>
<c:forEach items="${list }" var="food">
<tr>
<td>${food.id }</td>
<td>${food.name }</td>
<td>${food.price }</td>
<td>
<button onclick="del(${food.id })">刪除</button>
</td>
<td>
<button onclick="toUpdate(${food.id })">修改</button>
</td>
</tr>
</c:forEach>
</table>
<a href="add.jsp">新增</a>
</body>
</html>更新介面jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
</head>
<body>
<form action="action_update" method="post">
<input type="hidden" name="id" value="${food.id }">
姓名：<input type="text" value="${food.name }" name="name"><br>
價格：<input type="text" value="${food.price }" name="price"><br>
<input type="submit" value="提交">
</form>
</body>
</html>新增介面jsp：
<%@ page language="java" contentType="text/html; charset=UTF-8"
pageEncoding="UTF-8"%>
<%@ taglib uri="http://java.sun.com/jsp/jstl/core" prefix="c" %>
<!DOCTYPE html>
<html>
<head>
<meta charset="UTF-8">
<title>Insert title here</title>
<script type="text/javascript">
</script>
</head>
<body>
<form action="action_add" method="post">
<input type="hidden" name="food.id">
姓名：<input type="text" value="" name="name"><br>
價格：<input type="text" value="" name="price"><br>
<input type="submit" value="提交">
</form>
</body>
</html>寫這個簡單例子，主要是為了幫助剛剛接觸Struts2這個框架的初學者，能更好的去理解Struts2框架，並學會如何使用，如果有同學想要本例子中相關jar包，可以給博主要哦