Spring入门(0) Hello World

本过程通过IDEA+Maven的方式来展示，Spring的hello world；

新建spring项目 (java project类型)
使用该项目用maven
右击之后选择这个
编写pom.xml，加入相关依赖

<?xml version="1.0" encoding="UTF-8"?>
<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/xsd/maven-4.0.0.xsd">
    <modelVersion>4.0.0</modelVersion>

    <groupId>com.springdemo</groupId>
    <artifactId>SpringDemo</artifactId>
    <version>1.0-SNAPSHOT</version>
    <dependencies>
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.3.3.RELEASE</version>
            <type>pom</type>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.3.3.RELEASE</version>
        </dependency>



    </dependencies>
    
</project>

在这里插入图片描述
相关依赖已经全部导入进来了。maven管理包的话还是很方便的。
4. 编写service类

package com.springdemo.service;

public class WelcomeService {
    private String message;

    public String getMessage() {
        return message;
    }

    public void setMessage(String message) {
        this.message = message;
    }

    public void sayHello(){
        System.out.println(message);
    }
}

编写beans.xml文件，这个文件就是Java bean，Spring只是帮你创建好了。

<?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="ws" class="com.springdemo.service.WelcomeService">
        <property name="message" value="hello world"/>
    </bean>

</beans>

bean标签，就是创建一个Java bean。这就是spring的作用和目的。
6. 编写测试类。

 package com.springdemo;


import com.springdemo.service.WelcomeService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;

public class Test {
//创建容器
    ApplicationContext ac = new ClassPathXmlApplicationContext("beans.xml");
    WelcomeService ws = (WelcomeService)ac.getBean("ws");
    ws.sayHello();
}

Spring入门(0) Hello World

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