Spring学习笔记(01-HelloWorld)

1.使用IDEA创建Maven工程，在pom.xml文件中添加spring的四个核心jar包的依赖，以及junit测试依赖

<?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.xiao</groupId>
    <artifactId>spring_01</artifactId>
    <version>1.0-SNAPSHOT</version>

    <dependencies>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-core</artifactId>
            <version>4.2.5.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>4.2.5.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-beans</artifactId>
            <version>4.2.5.RELEASE</version>
        </dependency>

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-expression</artifactId>
            <version>4.2.5.RELEASE</version>
        </dependency>

        <!-- 测试 -->
        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.12</version>
        </dependency>

    </dependencies>

</project>

2.工程目录如下

3.写一个User实体类，准备放入spring容器中

package com.xiao.pojo;
/**
 * @Author 笑笑
 * @Date 21:01 2018/05/31
 */
public class User {

    private int id;
    private String username;
    private String password;

    public int getId() {
        return id;
    }

    public void setId(int id) {
        this.id = id;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

    @Override
    public String toString() {
        return "User{" +
                "id=" + id +
                ", username='" + username + '\'' +
                ", password='" + password + '\'' +
                '}';
    }
}

4.书写spring核心配置文件applicationContext.xml文件，并将User对象交给spring管理

<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
	xmlns="http://www.springframework.org/schema/beans"
	xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans-4.2.xsd ">

    <!-- name属性就是给注入到容器中的对象起个名字-->
	<bean name="user" class="com.xiao.pojo.User" />

</beans>

5.书写测试类SpringTest_01进行测试

import com.xiao.pojo.User;
import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
/**
 * @Author 笑笑
 * @Date 21:09 2018/05/31
 */
public class SpringTest_01 {

    @Test
    public void  test(){
        //创建容器对象
        ApplicationContext ac = new ClassPathXmlApplicationContext("applicationContext.xml");
        //从容器中获取user对象
        User user = (User) ac.getBean("user");
        //输出user对象
        System.out.println(user);
    }

}

测试的输出结果如下

表示从spring容器中获取对象成功！