Spring对Web应用的支持

案例一：设计Web程序，在jsp页面获取SpringIoC,并显示有关信息。

分析：首先在web.xml中配置信息，使之自动创建并装载SpringIoC容器，然后建立一个JavaBean，并包含获取信息的方法，最后设计jsp页面，获取信息并显示。

代码：

（1）创建web工程，并在web.xml中配置信息
<?xml version="1.0" encoding="UTF-8"?>
<web-app xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xmlns="http://xmlns.jcp.org/xml/ns/javaee" xsi:schemaLocation="http://xmlns.jcp.org/xml/ns/javaee http://xmlns.jcp.org/xml/ns/javaee/web-app_3_1.xsd" id="WebApp_ID" version="3.1">
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>
</web-app>

（2）设计JavaBean
package com.edu.spring.web.beans;

public class Person {	
	private String username;	
	public void setUsername(String username) {
		this.username = username;
	}	
	public String getUsername() {
		return username;
	}

	public String geyHello(){
		return "My name is " + username;
	}
	
}

（3）创建Spring的配置文件（applicationContext.xml),并添加配置Person的Bean
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
	xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">

	<bean id="person" 
		class="com.edu.spring.web.beans.Person">
		<property name="username" value="张三"></property>	
	</bean>	
	
</beans>

(4)设计jsp页面（index.jsp)
<%@page import="org.springframework.web.context.WebApplicationContext"%>
<%@page import="com.edu.spring.web.beans.Person"%>
<%@page import="org.springframework.web.context.support.WebApplicationContextUtils"%>
<%@page import="org.springframework.context.ApplicationContext"%>
<%@ 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>Spring Web 第一个案例</title>
</head>
<body>
	<%
		//1. 从 appication 域对象中得到 IOC 容器的实例
		ApplicationContext ctx = WebApplicationContextUtils
				.getWebApplicationContext(application);
		//2. 从 IOC 容器中得到 bean
		Person person = (Person) ctx.getBean(Person.class);
		//3. 使用 bean
	%>
	       从Bean中获取的信息：<%=person.geyHello()%>
</body>
</html>

案例二：通过servlet获取SpringIoC，并显示有关信息

分析：实现过程与案例一相同，只是将jsp页面替换为servlet即可。即设计servlet，并采用注释配置方式配置servlet

package com.edu.spring.web.servlet;

import java.io.IOException;
import java.io.PrintWriter;

import javax.servlet.ServletContext;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

import org.springframework.web.context.WebApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import com.edu.spring.web.beans.Person;

@WebServlet("/SpringIoC")
public class SpringIoC extends HttpServlet {
	private static final long serialVersionUID = 1L;

	public SpringIoC() {
		super();
	}

	protected void doGet(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		 doPost( request, response);
	}

	protected void doPost(HttpServletRequest request,
			HttpServletResponse response) throws ServletException, IOException {
		// (1)首先通过request对象，获取web服务器容器
		ServletContext sc = request.getServletContext();
		//(2)利用Spring框架提供的静态方法，从Web服务器中获取 Spring容器
		WebApplicationContext wact = WebApplicationContextUtils
				.getWebApplicationContext(sc);
		// (3) 从 IOC 容器中得到 bean
		Person person = (Person) wact.getBean(Person.class);
		// (4) 使用 bean		
		response.setCharacterEncoding("GBK");
		request.setCharacterEncoding("GBK");
		PrintWriter out = response.getWriter();		
		out.println(person.geyHello());		
	}

}

Flora_M

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