Spring的IOC容器-工具盒子

基于spring framework 4.x， jdk1.8

1.集成Spring到项目中 {#1-集成Spring到项目中}

IOC容器需要以下spring核心依赖项：spring-core, spring-beans, spring-context, spring-expression

创建maven项目，并引入spring核心依赖以及单元测试junit到pom.xml

<?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>

    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>example<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>Spring<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>1.0-SNAPSHOT<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>

    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependencies</span><span class="token punctuation">&gt;</span></span>

        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.springframework<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>spring-core<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>4.3.18.RELEASE<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>

        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.springframework<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>spring-beans<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>4.3.18.RELEASE<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>

        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.springframework<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>spring-context<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>4.3.18.RELEASE<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>

        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.springframework<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>spring-expression<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>4.3.18.RELEASE<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>

        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>dependency</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>junit<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>junit<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>version</span><span class="token punctuation">&gt;</span></span>4.12<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>version</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>scope</span><span class="token punctuation">&gt;</span></span>compile<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>scope</span><span class="token punctuation">&gt;</span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependency</span><span class="token punctuation">&gt;</span></span>

    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>dependencies</span><span class="token punctuation">&gt;</span></span>

    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>build</span><span class="token punctuation">&gt;</span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>plugins</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>plugin</span><span class="token punctuation">&gt;</span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>groupId</span><span class="token punctuation">&gt;</span></span>org.apache.maven.plugins<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>groupId</span><span class="token punctuation">&gt;</span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>artifactId</span><span class="token punctuation">&gt;</span></span>maven-compiler-plugin<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>artifactId</span><span class="token punctuation">&gt;</span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>configuration</span><span class="token punctuation">&gt;</span></span>
                    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>source</span><span class="token punctuation">&gt;</span></span>1.8<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>source</span><span class="token punctuation">&gt;</span></span>
                    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>target</span><span class="token punctuation">&gt;</span></span>1.8<span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>target</span><span class="token punctuation">&gt;</span></span>
                <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>configuration</span><span class="token punctuation">&gt;</span></span>
            <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>plugin</span><span class="token punctuation">&gt;</span></span>
        <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>plugins</span><span class="token punctuation">&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>build</span><span class="token punctuation">&gt;</span></span>



</project>

2.新建spring配置文件spring.xml在main/resources文件夹下

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

3.新建一个测试类com.example.test.MainTest在main/java下

package com.example.test;

import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;


public class MainTest {

}

2.基于XML配置Bean {#2-基于XML配置Bean}

2.1通过反射配置Bean {#2-1通过反射配置Bean}

1.通过全类名反射的方式在ioc容器中创建bean

新建一个JavaBean对象com.example.bean.Bean在main/java下，通过全类名反射的方式需要bean实现无参构造器

package com.example.bean;

public class Bean {
private String name;


    <span class="token keyword">public</span> <span class="token class-name">Bean</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"bean 无参构造"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token class-name">Bean</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span><span class="token string">"bean 有参构造"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token class-name">String</span> <span class="token function">getName</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token keyword">public</span> <span class="token keyword">void</span> <span class="token function">setName</span><span class="token punctuation">(</span><span class="token class-name">String</span> name<span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">this</span><span class="token punctuation">.</span>name <span class="token operator">=</span> name<span class="token punctuation">;</span>
    <span class="token punctuation">}</span>

    <span class="token annotation punctuation">@Override</span>
    <span class="token keyword">public</span> <span class="token class-name">String</span> <span class="token function">toString</span><span class="token punctuation">(</span><span class="token punctuation">)</span> <span class="token punctuation">{</span>
        <span class="token keyword">return</span> <span class="token string">"Bean{"</span> <span class="token operator">+</span>
                <span class="token string">"name='"</span> <span class="token operator">+</span> name <span class="token operator">+</span> <span class="token char">'\''</span> <span class="token operator">+</span>
                <span class="token char">'}'</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>



}

spring.xml中通过<bean>配置bean，class设置为bean的全类名，id用于引用bean，id在ioc容器中必须是唯一的

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

    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>bean<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>com.example.bean.Bean<span class="token punctuation">"</span></span><span class="token punctuation">&gt;</span></span>
       <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>property</span> <span class="token attr-name">name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>name<span class="token punctuation">"</span></span> <span class="token attr-name">value</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>lzj<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>
    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;/</span>bean</span><span class="token punctuation">&gt;</span></span>

    <span class="token tag"><span class="token tag"><span class="token punctuation">&lt;</span>bean</span> <span class="token attr-name">id</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>bean2<span class="token punctuation">"</span></span> <span class="token attr-name">class</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>com.example.bean.Bean<span class="token punctuation">"</span></span> <span class="token attr-name"><span class="token namespace">p:</span>name</span><span class="token attr-value"><span class="token punctuation attr-equals">=</span><span class="token punctuation">"</span>lzj<span class="token punctuation">"</span></span><span class="token punctuation">/&gt;</span></span>



</beans>

Spring提供了两种ioc容器的实现，BeanFactory和ApplicationContext，BeanFactory是ioc容器的基本实现，ApplicationContext是BeanFactory的子接口，提供了更加高级的特性

ApplicationContext的主要实现类有

ClassPathXmlApplicationContext 从类路径下加载配置文件
FileSystemXmlApplicationContext 从文件系统加载配置文件
WebApplicationContext 专门为web应用所准备，从web根目录的路径中完成初始化

ApplicationContext在初始化上下文时就会实例化所有单例的Bean

package com.example.test;

import com.example.bean.Bean;


import org.junit.Test;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;


public class MainTest {
@Test
public void testBean() {
// 根据spring.xml配置文件启动spring-ioc容器，ioc容器启动，并且会调用无参构造器
ApplicationContext context = new ClassPathXmlApplicationContext("spring.xml");


        <span class="token comment">//从ioc容器中获取bean实例</span>
        <span class="token class-name">Bean</span> bean <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Bean</span><span class="token punctuation">)</span> context<span class="token punctuation">.</span><span class="token function">getBean</span><span class="token punctuation">(</span><span class="token string">"bean"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>bean<span class="token punctuation">)</span><span class="token punctuation">;</span>

        <span class="token class-name">Bean</span> bean2 <span class="token operator">=</span> <span class="token punctuation">(</span><span class="token class-name">Bean</span><span class="token punctuation">)</span> context<span class="token punctuation">.</span><span class="token function">getBean</span><span class="token punctuation">(</span><span class="token string">"bean2"</span><span class="token punctuation">)</span><span class="token punctuation">;</span>
        <span class="token class-name">System</span><span class="token punctuation">.</span>out<span class="token punctuation">.</span><span class="token function">println</span><span class="token punctuation">(</span>bean2<span class="token punctuation">)</span><span class="token punctuation">;</span>
    <span class="token punctuation">}</span>



}

输出

bean 无参构造
Bean{name='lzj'}
bean 无参构造
Bean{name='lzj'}

51工具盒子

Spring的IOC容器

1.集成Spring到项目中 {#1-集成Spring到项目中}

2.基于XML配置Bean {#2-基于XML配置Bean}

2.1通过反射配置Bean {#2-1通过反射配置Bean}

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