spring实践1_IOC/DI

写在前面：spring框架的火热不言而喻，为此学习spring是有必要的。热衷于实践的我更喜欢用案例来分析与理解。从今天开始，我们来走近spring，

　　　　　    希望通过这些简单的案例能够让我们对spring有个简单的了解，并达到入门水平。

准备材料：1.IDE：eclipse，

　　　　　  2.JDK：1.8，

　　　　　  3.JARS：spring核心包

学习目标：1.spring注入属性

　　　　　  2.spring注入对象

　　　　　  3.spring注解注入方式

一.spring注入属性

　　1.pojo实体类Category

package com.practice.pojo;

public class Category {
    private int id;
    private String name;

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

　　2.spring核心配置文件。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"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
   http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/aop
   http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
   http://www.springframework.org/schema/tx
   http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
   http://www.springframework.org/schema/context     
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">
   
   <!-- 配置第一个bean -->
       <bean id="c" class="com.practice.pojo.Category">
           <property name="name"  value="category1"></property>
       </bean>
       
</beans>

　　3.编写测试类

package com.practice.test;

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

import com.practice.pojo.Category;

public class TestSpring {
    public static void main (String args[]){
        ApplicationContext context=new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml"});
        Category c1=(Category)context.getBean("c");
        System.out.println(c1.getName());
    }
}

　　4.运行结果

九月 24, 2019 1:59:05 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@2e5d6d97: startup date [Tue Sep 24 13:59:05 CST 2019]; root of context hierarchy
九月 24, 2019 1:59:05 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
category1

二.spring注入对象

　　1.pojo实体类Product

package com.practice.pojo;

public class Product {
    private int id;
    private String name;
    private Category category;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Category getCategory() {
        return category;
    }
    public void setCategory(Category category) {
        this.category = category;
    }
    
}

　　2.Spring核心配置文件。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"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
   http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/aop
   http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
   http://www.springframework.org/schema/tx
   http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
   http://www.springframework.org/schema/context     
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">
   
   <!-- 配置第一个bean -->
       <bean id="c" class="com.practice.pojo.Category">
           <property name="name"  value="category1"></property>
       </bean>
       <!-- 配置第二个bean -->
       <bean id="p" class="com.practice.pojo.Product">
           <property name="category" ref="c"></property>
       </bean>
</beans>

　　3.测试类

package com.practice.test;

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

import com.practice.pojo.Product;

public class TestSpring {
    public static void main (String args[]){
        ApplicationContext context=new ClassPathXmlApplicationContext(new String[]{"applicationContext.xml"});
//        Category c1=(Category)context.getBean("c");
//        System.out.println(c1.getName());
        Product p1=(Product)context.getBean("p");
        System.out.println(p1.getCategory().getName());
    }
}

　　4.运行结果

九月 24, 2019 2:46:56 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@6433a2: startup date [Tue Sep 24 14:46:56 CST 2019]; root of context hierarchy
九月 24, 2019 2:46:57 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
category1

三.spring注解注入方式（注解属性对象）

　　
　　1.对上面已经存在的文件进行修改，修改Spring核心配置文件。applicaitonContext.xml  (红色部分是修改的部分)

<?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:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
   http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/aop
   http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
   http://www.springframework.org/schema/tx
   http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
   http://www.springframework.org/schema/context     
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">
   
   <!-- 开放注解功能 -->
   <context:annotation-config></context:annotation-config>
   <!-- 配置第一个bean -->
       <bean id="c" class="com.practice.pojo.Category">
           <property name="name"  value="category1"></property>
       </bean>
       <!-- 配置第二个bean -->
       <bean id="p" class="com.practice.pojo.Product">
           <!--  <property name="category" ref="c"></property>-->
       </bean>
       
</beans>

　　2.Product实体类

package com.practice.pojo;

import org.springframework.beans.factory.annotation.Autowired;

public class Product {
    private int id;
    private String name;
    //这一行的下一行  " @Autowired " 可以换成  " @Resource(name="c")"
    @Autowired 
    private Category category;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Category getCategory() {
        return category;
    }
    //如果上面的注解你都没用，那么你在下一行可以写上注解  “@Autowired" 
    public void setCategory(Category category) {
        this.category = category;
    }
    
}

//以上三种注解方式都可以实现同样的预期结果。

　　3.运行结果

九月 24, 2019 2:46:56 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@6433a2: startup date [Tue Sep 24 14:46:56 CST 2019]; root of context hierarchy
九月 24, 2019 2:46:57 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
category1

四.spring注解注入方式（注解bean）

　　1.修改Spring配置文件applicaitonContext.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"
    xmlns:aop="http://www.springframework.org/schema/aop"
    xmlns:tx="http://www.springframework.org/schema/tx"
    xmlns:context="http://www.springframework.org/schema/context"
    xsi:schemaLocation="
   http://www.springframework.org/schema/beans
   http://www.springframework.org/schema/beans/spring-beans-3.0.xsd
   http://www.springframework.org/schema/aop
   http://www.springframework.org/schema/aop/spring-aop-3.0.xsd
   http://www.springframework.org/schema/tx
   http://www.springframework.org/schema/tx/spring-tx-3.0.xsd
   http://www.springframework.org/schema/context     
   http://www.springframework.org/schema/context/spring-context-3.0.xsd">
   
  <context:component-scan base-package="com.practice.pojo"></context:component-scan>
       
</beans>

　　2.修改Product类

package com.practice.pojo;

import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Component;
@Component("p")
public class Product {
    private int id;
    private String name="product1";
    //这一行的下一行  " @Autowired " 可以换成  " @Resource(name="c")"
    @Autowired 
    private Category category;
    public int getId() {
        return id;
    }
    public void setId(int id) {
        this.id = id;
    }
    public String getName() {
        return name;
    }
    public void setName(String name) {
        this.name = name;
    }
    public Category getCategory() {
        return category;
    }
    //如果上面的注解你都没用，那么你在下一行可以写上注解  “@Autowired" 
    public void setCategory(Category category) {
        this.category = category;
    }
    
}

//以上三种注解方式都可以实现同样的预期结果。

　　3.修改Category类

package com.practice.pojo;

import org.springframework.stereotype.Component;

@Component("c")
public class Category {
    private int id;
    private String name="category1";

    public int getId() {
        return id;
    }

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

    public String getName() {
        return name;
    }

    public void setName(String name) {
        this.name = name;
    }

}

　4.运行结果

九月 24, 2019 3:22:23 下午 org.springframework.context.support.AbstractApplicationContext prepareRefresh
信息: Refreshing org.springframework.context.support.ClassPathXmlApplicationContext@6433a2: startup date [Tue Sep 24 15:22:23 CST 2019]; root of context hierarchy
九月 24, 2019 3:22:24 下午 org.springframework.beans.factory.xml.XmlBeanDefinitionReader loadBeanDefinitions
信息: Loading XML bean definitions from class path resource [applicationContext.xml]
category1

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-------------------------------------------分割线,以上我相信很容易看出异同，学习一个东西，首先是模仿，以后我会讲一讲我对控制反转和依赖注入的深入理解-------------------------------

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原文地址：https://www.cnblogs.com/zuoluwo/p/11577137.html