Spring_mvc ioc/DI 控制反转与依赖注入

最新推荐文章于 2024-04-22 23:46:35 发布

chou_out_man

最新推荐文章于 2024-04-22 23:46:35 发布

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本文链接：https://blog.youkuaiyun.com/chou_out_man/article/details/61191234

本文介绍了一个使用Spring框架实现的商品展示应用案例，包括了页面跳转、商品实体类定义、控制类实现及Spring IoC容器配置等内容。

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主要步骤：
1. 提交页面：一个查看商品的链接
结果页面：商品列表，显示三件商品的具体信息
2. 实体类：商品名称，价格
3. 后台控制类Servlet和配置
4. 添加spring开发包
5. 实体类改进：Spring IoC配置

控制类改进：Spring IoC程序

提交页面一个查看商品的链接：

<%@ page language="java" import="java.util.*" pageEncoding="UTF-8"%>
<%
String path = request.getContextPath();
String basePath = request.getScheme()+"://"+request.getServerName()+":"+request.getServerPort()+path+"/";
%>

<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN">
<html>
  <head>
    <base href="<%=basePath%>">
    
    <title>My JSP 'index.jsp' starting page</title>
	<meta http-equiv="pragma" content="no-cache">
	<meta http-equiv="cache-control" content="no-cache">
	<meta http-equiv="expires" content="0">    
	<meta http-equiv="keywords" content="keyword1,keyword2,keyword3">
	<meta http-equiv="description" content="This is my page">
	<!--
	<link rel="stylesheet" type="text/css" href="styles.css">
	-->
  </head>
  
  <body>
    This is my JSP page. <br>
    <a href="domain">查看已购买的商品</a>
  </body>
</html>

实体类Product

注意：实体勒种必须要有无参构造函数，否则在applicationContext.xml配置文件中将会报错

No constructor with 0 arguments defined in class 'Spring_modle.Product' applicationContext.xml /Spring_Ioc_DI/src line 7 Spring Beans Problem

package Spring_modle;

public class Product {
	/**
	 * @return the name
	 */
	public String getName() {
		return name;
	}
	/**
	 * @param name the name to set
	 */
	public void setName(String name) {
		this.name = name;
	}
	/**
	 * @return the pirce
	 */
	public double getPirce() {
		return pirce;
	}
	/**
	 * @param pirce the pirce to set
	 */
	public void setPirce(double pirce) {
		this.pirce = pirce;
	}
	private String name;
	private double pirce;
	/**
	 * 有参构造
	 * @param name
	 * @param pirce
	 */
	public Product(String name, double pirce) {
		super();
		this.name = name;
		this.pirce = pirce;
	}
	
	/**
	 * @author  tianjie
	 *Spring注入必须要有无参构造，否则 applicationContext.xml将会报错
	 * 无参构造
	 * */
	public Product() {
		
	}
}

后台控制类servlet

package Spring_Control;

import java.io.IOException;
import java.util.ArrayList;
import java.util.List;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import javax.servlet.http.HttpSession;

import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

import Spring_modle.Product;

public class domain extends HttpServlet {

	


	public void doGet(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {

		this.doPost(request, response);
	}

	
	public void doPost(HttpServletRequest request, HttpServletResponse response)
			throws ServletException, IOException {
		/**
		 * 静态获取
		 * */
//		ApplicationContext con=
//				new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml"});
//		
//		Proudect p1,p2,p3;
//		p1=con.getBean("p1",Proudect.class);
//		p2=con.getBean("p2",Proudect.class);
//		p3=con.getBean("p3",Proudect.class);
//		
//		List<Proudect> list=new ArrayList<Proudect>();
//		list.add(p1);
//		list.add(p2);
//		list.add(p3);
		/**
		 * 动态获取
		 * */
		ApplicationContext con=
				new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml"});
		String[] p=con.getBeanNamesForType(Product.class);
		List<Product> list=new ArrayList<Product>();
		Product proudect;
		for(int i=0;i<p.length;i++){
			proudect=con.getBean(p[i],Product.class);
			list.add(proudect);
		}
		HttpSession session=request.getSession();
		session.setAttribute("list", list);
		response.sendRedirect("details.jsp");
	
	}

	
}

applicationContext.xml配置文件

<?xml version="1.0" encoding="UTF-8"?>
<beans
	xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns:p="http://www.springframework.org/schema/p"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-3.0.xsd">
<bean name="p1" class="Spring_modle.Product" ><!-- 控制反转 -->
	<property name="name" value="化妆品"></property><!-- 依赖注入 -->
	<property name="pirce" value="300"></property>
</bean>

<bean name="p2" class="Spring_modle.Product"><!-- 控制反转 -->
	<property name="name" value="轮滑鞋"></property><!-- 依赖注入 -->
	<property name="pirce" value="500"></property>
</bean>

<bean name="p3" class="Spring_modle.Product"><!-- 控制反转 -->
	<property name="name" value="书"></property><!-- 依赖注入 -->
	<property name="pirce" value="30"></property>
</bean>

</beans>

结果页面 details.jsp

<%@page import="java.util.List"%>
<%@page import="Spring_modle.Proudect"%>
<%@ page language="java" contentType="text/html; charset=UTF-8"
    pageEncoding="UTF-8"%>
<!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>Insert title here</title>
</head>
<body>
	<center>
	<%
	out.write("输出商品：<br>");
	List<Proudect> list=(List<Proudect>)session.getAttribute("list");
	for(int i=0;i<list.size();i++){
		out.write("商品名称："+list.get(i).getName()+"<br>");
		out.write("商品名称："+list.get(i).getPirce()+"<br>");
	}
	 %>
	 </center>
</body>
</html>