Spring在Web项目中的使用

对于在web项目中使用Spring，一直有想法，但是没有去实践，今天心血来潮就试了一次。现在讲工程代码放出来供大家学习。

引用jar包

spring-context
spring-beans
spring-core
spring-web
spring-aop
javax.servlet-api
commons-logging

pom.xml

<project xmlns="http://maven.apache.org/POM/4.0.0" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
     xsi:schemaLocation="http://maven.apache.org/POM/4.0.0 http://maven.apache.org/maven-v4_0_0.xsd">
<modelVersion>4.0.0</modelVersion>
<groupId>com.chen</groupId>
<artifactId>Spring-In-Webapp</artifactId>
<packaging>war</packaging>
<version>1.0-SNAPSHOT</version>
<name>Spring-In-Webapp Maven Webapp</name>
<url>http://maven.apache.org</url>
<dependencies>

    <!--
        为spring核心提供了大量扩展。可以找到使用spring applicationcontext特性时所需的全部类，
        jdni所需的全部类，ui方面的用来与模板(templating)引擎如 velocity、freemarker、
        jasperreports集成的类，以及校验validation方面的相关类，还有ejb,cache,format,jms等等。
    -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-context</artifactId>
        <version>4.3.12.RELEASE</version>
    </dependency>

    <!--
        springioc（依赖注入）的基础实现，所有应用都要用到的，它包含访问配置文件、创建和管理bean以及
        进行inversion of control / dependency injection（ioc/di）操作相关的所有类。
        但是这个是个基础实现，一般我们在实际的开发过程中很少直接用到，它是对起到支撑作用的。
    -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-beans</artifactId>
        <version>4.3.12.RELEASE</version>
    </dependency>

    <!--
        spring的核心包，包含spring框架基本的核心工具类，spring其它组件要都要使用到这个包里的类，是其它
        组件的基本核心。包括asm，cglib以及相关的工具类
    -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-core</artifactId>
        <version>4.3.12.RELEASE</version>
    </dependency>

    <!--
        包含web应用开发时，用到spring框架时所需的核心类，包括自动载入webapplicationcontext特性的类、
        struts与jsf集成类、文件上传的支持类、filter类和大量工具辅助类。
    -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-web</artifactId>
        <version>4.3.12.RELEASE</version>
    </dependency>

    <!-- 包含在应用中使用spring的aop特性时所需的类。 -->
    <dependency>
        <groupId>org.springframework</groupId>
        <artifactId>spring-aop</artifactId>
        <version>4.3.12.RELEASE</version>
    </dependency>

    <!-- https://mvnrepository.com/artifact/javax.servlet/javax.servlet-api -->
    <dependency>
        <groupId>javax.servlet</groupId>
        <artifactId>javax.servlet-api</artifactId>
        <version>3.1.0</version>
        <scope>provided</scope>
    </dependency>

    <dependency>
        <groupId>commons-logging</groupId>
        <artifactId>commons-logging</artifactId>
        <version>1.1.1</version>
    </dependency>


    <dependency>
        <groupId>junit</groupId>
        <artifactId>junit</artifactId>
        <version>4.12</version>
    </dependency>
</dependencies>
<build>
    <finalName>Spring-In-Webapp</finalName>
</build>
</project>

项目结构

代码

HelloService.java

    package service;

    /**
     * Created by handsome programmer.
     * User: chen
     * Date: 2018/1/21
     * Time: 17:38
     * Description:
     */
    public class HelloService {
        public String getUsername(String str) {
            return "Hello " + str;
        }
    }

HelloSpring.java

package servlet;

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

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 java.io.IOException;

/**
 * Created by handsome programmer.
 * User: chen
 * Date: 2018/1/21
 * Time: 17:24
 * Description:
 */
@WebServlet(name = "hello", urlPatterns = "/hello")
public class HelloSpring extends HttpServlet {
    private HelloService helloService;

    @Override
    protected void service(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        request.setCharacterEncoding("UTF-8");
        String message = request.getParameter("username");
        //获取Spring容器
        WebApplicationContext applicationContext = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
        System.out.println("applicationContext = " + applicationContext);
        helloService = applicationContext.getBean("helloService", HelloService.class);

        System.out.println("message = " + message);
        message = helloService.getUsername(message);
        request.setAttribute("message", message);
        request.getRequestDispatcher("index.jsp").forward(request, response);
    }
}

applicationContext.xml\

<?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="helloService" class="service.HelloService"/>
</beans>

web.xml

<!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>
    <display-name>Archetype Created Web Application</display-name>

    <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>

index.jsp

<%--
  Created by IntelliJ IDEA.
  User: chen
  Date: 2018/1/21
  Time: 17:44
  To change this template use File | Settings | File Templates.
--%>
<%@ page contentType="text/html;charset=UTF-8" language="java" %>
<html>
<head>
    <title>Hehe</title>
</head>
<body>
<h1>
   <%=request.getAttribute("message")%>
</h1>
</body>
</html>

访问链接：http://localhost:8080/hello?username=admin
访问效果

网页
网页效果

后台
idea输出

Spring在web中的使用

Spring在Web项目中的使用

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