使用Spring框架入门一：基于XML配置的IOC/DI的使用

一、Spring框架

　　1、方法一：逐项导入基础依赖包：

　　　　spring-core、spring-beans、spring-context、spring-expression

　　2、方法二：最简洁的导入，直接导入spring-context包：　　

        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.0.5.RELEASE</version>
        </dependency>

　　在pom.xml中加入上spring-context的依赖，它便会自动导入上述四个包。

　　3、参考本项目结构图：

　　

二、操作案例

　　1、建立几个类对象，便于测试。

　　

package test1;

import lombok.Data;

@Data
public class User {

    private String name;
    private int age;

    public void add() {
        System.out.println("user add method executed.");
    }

}

　　注意，此类中，使用了lombok框架的@Data方式来实现的Getter和Setter和无参构造函数。引入lombok的方法是添加下列依赖，并为Idea安装一个lombok的插件，并启动注释的编译：

<!-- https://mvnrepository.com/artifact/org.projectlombok/lombok -->
<dependency>
    <groupId>org.projectlombok</groupId>
    <artifactId>lombok</artifactId>
    <version>1.16.20</version>
    <scope>provided</scope>
</dependency>

　　2、建立一个非静态的工厂类，用于测试非静态工厂方式创建Bean。

package test1;

public class UserFactory {
    public User createUser() {
        User user = new User();
        user.setAge(12);
        user.setName("张三");
        return user;
    }
}

　　3、再创建一个的工厂类，添加一个静态方法，用于测试静态方法创建Bean。

package test1;

public class UserStaticFactory {
    public static User createUser() {
        User user = new User();
        user.setAge(22);
        user.setName("张五");
        return user;
    }
}

　　4、再建立一个Student类，用来测试多种不同构造函数的情况：

package test1;

import lombok.Data;

import java.util.List;
import java.util.Map;

@Data
public class Student {
    private final String name;
    private final int age;
    private List<User> users;
    private User user;
    private Map<String, String> map;

    public Student(String name, int age) {
        this.name = name;
        this.age = age;
    }

    public Student(User user) {
        this.user = user;
        this.name = "另外一个有参数构建Name1";
        this.age = 2;
    }

    public Student(List<User> users) {
        this.users = users;
        this.name = "另外一个有参数构建Name2";
        this.age = 33;
    }

    public Student(Map<String, String> map) {
        this.map = map;
        this.name = "另外一个有参数构建Name2";
        this.age = 33;
    }
}

　　5、在Maven项目的resources中添加一个xml（在WEB项目中要放在/WEB-INF/下），官方建议命名为：applicationContext.xml，我们为了方便做多项测试，因此就故意起个别的名字，比如：applicationContextTest1.xml，内容如下：

<?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">
    <!--方式一：直接创建-->
    <bean id="myUser1" class="test1.User">
        <property name="name" value="songxingzhu"/>
        <property name="age" value="10"/>
    </bean>

    <!--方式二：非静态工厂创建-->
    <bean id="userFactory" class="test1.UserFactory"/>
    <!--使用scope设置为prototype（默认为singleton）让每次产生新实例-->
    <bean id="myUser2" factory-bean="userFactory" factory-method="createUser" scope="prototype">
        <property name="name" value="修改后的Name"/>
    </bean>

    <!--方式三：静态方法创建-->
    <bean id="myUser3" class="test1.UserStaticFactory" factory-method="createUser"></bean>

    <!--构建函数的情况一：普通参数 -->
    <bean id="myStudent1" class="test1.Student">
        <constructor-arg name="name" value="Sindrol"/>
        <constructor-arg name="age" value="23"/>
    </bean>
    <!--构建函数的情况二：Bean -->
    <bean id="myStudent2" class="test1.Student">
        <constructor-arg name="user" type="test1.User" ref="myUser3"/>
    </bean>
    <!--构建函数的情况三：Map -->
    <bean id="myStudent3" class="test1.Student">
        <constructor-arg name="map">
            <map key-type="java.lang.String" value-type="java.lang.String">
                <entry key="key1" value="value1"/>
                <entry key="key2" value="value2"/>
            </map>
        </constructor-arg>
    </bean>
    <!--构建函数的情况四：List -->
    <bean id="myStudent4" class="test1.Student">
        <constructor-arg name="users">
            <array>
                <ref bean="myUser1"/>
                <ref bean="myUser2"/>
            </array>
        </constructor-arg>
    </bean>
</beans>

　　6、调用Spring框架

　　（1）调用代码：

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import test1.Student;
import test1.User;

public class BeanTest {
    @Test
    public void test1() {
        ApplicationContext context = new ClassPathXmlApplicationContext("applicationContextTest1.xml");
        User myUser1 = (User) context.getBean("myUser1");
        System.out.println(myUser1);
        User myUser2 = (User) context.getBean("myUser2");
        System.out.println(myUser2);
        User myUser2_2 = (User) context.getBean("myUser2");
        System.out.println("[user2==myUser2_2]:" + (myUser2 == myUser2_2));
        User myUser3 = (User) context.getBean("myUser3");
        System.out.println(myUser3);

        Student student1 = (Student) context.getBean("myStudent1");
        System.out.println(student1);
        Student student2 = (Student) context.getBean("myStudent2");
        System.out.println(student2);
        Student student3 = (Student) context.getBean("myStudent3");
        System.out.println(student3);
        Student myStudent4 = (Student) context.getBean("myStudent4");
        System.out.println(myStudent4);

    }
}

　　（2）测试结果：

"C:\Program Files\Java\jdk1.8.0_161\bin\java" -ea -Didea.test.cyclic.buffer.size=1048576 "-javaagent:D:\Application\DevTools\JetBrains\IntelliJ IDEA 2018.1\lib\idea_rt.jar=9042:D:\Application\DevTools\JetBrains\IntelliJ IDEA 2018.1\bin" -Dfile.encoding=UTF-8 -classpath "D:\Application\DevTools\JetBrains\IntelliJ IDEA 2018.1\lib\idea_rt.jar;D:\Application\DevTools\JetBrains\IntelliJ IDEA 2018.1\plugins\junit\lib\junit-rt.jar;D:\Application\DevTools\JetBrains\IntelliJ IDEA 2018.1\plugins\junit\lib\junit5-rt.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\charsets.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\deploy.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\access-bridge-64.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\cldrdata.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\dnsns.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\jaccess.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\jfxrt.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\localedata.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\nashorn.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunec.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunjce_provider.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunmscapi.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\sunpkcs11.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\ext\zipfs.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\javaws.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\jce.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\jfr.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\jfxswt.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\jsse.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\management-agent.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\plugin.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\resources.jar;C:\Program Files\Java\jdk1.8.0_161\jre\lib\rt.jar;D:\Projects\JavaProjects\StudyDemo\SpringDemo\target\test-classes;C:\Users\Sindrol\.m2\repository\org\springframework\spring-context\5.0.5.RELEASE\spring-context-5.0.5.RELEASE.jar;C:\Users\Sindrol\.m2\repository\org\springframework\spring-aop\5.0.5.RELEASE\spring-aop-5.0.5.RELEASE.jar;C:\Users\Sindrol\.m2\repository\org\springframework\spring-beans\5.0.5.RELEASE\spring-beans-5.0.5.RELEASE.jar;C:\Users\Sindrol\.m2\repository\org\springframework\spring-core\5.0.5.RELEASE\spring-core-5.0.5.RELEASE.jar;C:\Users\Sindrol\.m2\repository\org\springframework\spring-jcl\5.0.5.RELEASE\spring-jcl-5.0.5.RELEASE.jar;C:\Users\Sindrol\.m2\repository\org\springframework\spring-expression\5.0.5.RELEASE\spring-expression-5.0.5.RELEASE.jar;C:\Users\Sindrol\.m2\repository\junit\junit\4.12\junit-4.12.jar;C:\Users\Sindrol\.m2\repository\org\hamcrest\hamcrest-core\1.3\hamcrest-core-1.3.jar;C:\Users\Sindrol\.m2\repository\org\projectlombok\lombok\1.16.20\lombok-1.16.20.jar" com.intellij.rt.execution.junit.JUnitStarter -ideVersion5 -junit4 BeanTest,test1
五月 05, 2018 7:47:45 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@22a71081: startup date [Sat May 05 19:47:45 CST 2018]; root of context hierarchy
五月 05, 2018 7:47:45 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContextTest1.xml]
User(name=songxingzhu, age=10)
User(name=修改后的Name, age=12)
[user2==myUser2_2]:false
User(name=张五, age=22)
Student(name=Sindrol, age=23, users=null, user=null, map=null)
Student(name=另外一个有参数构建Name1, age=2, users=null, user=User(name=张五, age=22), map=null)
Student(name=另外一个有参数构建Name2, age=33, users=null, user=null, map={key1=value1, key2=value2})
Student(name=另外一个有参数构建Name2, age=33, users=[User(name=songxingzhu, age=10), User(name=修改后的Name, age=12)], user=null, map=null)