控制反转IOC

IoC ：Inverse of control 控制反转，思想就是在项目中引入一个工厂容器，对项目中接口依赖对象的创建，实现项目中对于依赖对象解耦合。

将程序中对象的创建权，交给工厂容器来管理
Spring其实就是一个工厂，出现为了解除程序中耦合，底层原理：工厂、配置文件、反射。程序不需要自己创建对象，获取spring工厂已经创建好的对象，对象创建权，反转到spring容器。

依赖注入DI

动态将某种依赖关系注入到对象之中。

例如: UserService中的UserDao变量就可使用依赖注入

Bean的作用域

singleton单例默认一个IOC容器里只有一个对应的实例化对象

prototype多例

IOC容器在初始化时,会把容器中的所有单例Bean实例化, 默认调用无参构造,如果Bean设置了初始化方法init, 还会执行初始化方法, 在IOC容器关闭时, 单例Bean的销毁方法才会执行.

IOC容器配置 XML方法

配置文件配置<bean标签> 必要属性 id class

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:p="http://www.springframework.org/schema/p"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd">


    <bean id="userDao" class="com.hrh.a_quickstart.UserDaoImpl"/>
    <bean id="userService" class="com.hrh.a_quickstart.UserServiceImpl">
        <property name="userDao" ref="userDao"/>
    </bean>

    <bean id="bean1" class="com.hrh.b_definition.Bean1"/>
    <bean id="bean2" class="com.hrh.b_definition.Bean2Factory" factory-method="initBean2"/>
    <bean id="bean3Factory" class="com.hrh.b_definition.Bean3Factory"/>
    <bean id="bean3" factory-bean="bean3Factory" factory-method="createBean3"/>
    <bean id="bean3_2" class="com.hrh.b_definition.MyFactoryBean"/>


    <bean id="singleBean" class="com.hrh.c_scope.SingletonBean"/>
    <bean id="prototypeBean" class="com.hrh.c_scope.PrototypeBean" scope="prototype"/>

    
    <bean id="lifecycleBean" class="com.hrh.d_lifecycle.LifeCycleBeanImpl" init-method="init" destroy-method="destroy" scope="prototype"/>


    <bean id="car" class="com.hrh.e_di.Car">
        <constructor-arg index="0" value="保时捷"/>
        <constructor-arg index="1" value="5000000"/>
    </bean>

    <!--<bean id="employee" class="com.hrh.e_di.Employee">
        <property name="name" value="张三"/>
        <property name="car" ref="car"/>
    </bean>-->
    <bean id="employee" class="com.hrh.e_di.Employee" p:name="李四" p:car-ref="car"/>

    <bean id="collectionBean" class="com.hrh.e_di.CollectionBean">
        <property name="list">
            <list>
                <value>abc</value>
                <value>def</value>
            </list>
        </property>
        <property name="set">
            <set>
                <value>1</value>
                <value>1</value>
                <value>2</value>
            </set>
        </property>
        <property name="map">
            <map>
                <entry key="aa" value="11"/>
                <entry key="bb" value="22"/>
            </map>
        </property>
        <property name="properties">
            <props>
                <prop key="qwe">111</prop>
                <prop key="ewq">222</prop>
            </props>
        </property>

    </bean>

</beans>

IOC容器配置注解方式

1 配置文件扫描包及包后代类中所有有注解的类

2 类上添加注解相当于XML的<bean>标签

3 @value 给变量注入值相当于XML的<property>

<?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:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">



    <context:component-scan base-package="com.hrh"/>

</beans>

package com.hrh.b;

import org.springframework.stereotype.Repository;

@Repository("userDao")
public class UserDaoImpl implements UserDao {
    @Override
    public void findByUsernameAndPassword() {
        System.out.println("持久层  findByUsernameAndPassword ...");
    }
}

package com.hrh.a;

import com.hrh.b.UserDao;
import org.springframework.beans.factory.annotation.Value;
import org.springframework.stereotype.Component;
import org.springframework.stereotype.Service;

@Service("userService")
public class UserServiceImpl implements UserService {

    @Value("#{userDao}")
    private UserDao userDao;

    public void setUserDao(UserDao userDao){
        this.userDao=userDao;
    }

    @Override
    public void login() {

        System.out.println("业务层 login ...");
        userDao.findByUsernameAndPassword();

    }
}

package com.hrh.a;

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

import java.lang.reflect.InvocationTargetException;
import java.lang.reflect.Method;

public class test {

    @Test
    public void testBeanDefinition() throws NoSuchMethodException, InvocationTargetException, IllegalAccessException {
        ApplicationContext applicationContext = new ClassPathXmlApplicationContext(
                "applicationContext.xml");
        UserService userService = (UserService) applicationContext
                .getBean("userService");
        userService.login();
        
    }
}

Spring和Junit集成测试

在测试类中加入这两个注解
初始化容器
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath: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:content="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">


    <bean id="userDao" class="com.hrh.test.UserDao"/>
    <bean id="userService" class="com.hrh.test.UserService">
        <property name="userDao" ref="userDao"/>
    </bean>

</beans>

package com.hrh.test;


import org.junit.Test;
import org.junit.runner.RunWith;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.beans.factory.annotation.Qualifier;
import org.springframework.test.context.ContextConfiguration;
import org.springframework.test.context.junit4.SpringJUnit4ClassRunner;


@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = "classpath:applicationContext.xml")
public class test {

    @Autowired
    @Qualifier("userService")
    private UserService userService;
    @Test
    public void test1(){

        userService.login();

    }

}

结合WEB代码

web.xml 配置信息

listener 监听器监听容器的创建

全局配置信息配置applicationContext.xml的的路径

<!DOCTYPE web-app PUBLIC
 "-//Sun Microsystems, Inc.//DTD Web Application 2.3//EN"
 "http://java.sun.com/dtd/web-app_2_3.dtd" >

<web-app>
  <display-name>Archetype Created Web Application</display-name>
  
  <context-param>
    <param-name>contextConfigLocation</param-name>
    <param-value>classpath:applicationContext.xml</param-value>
  </context-param>
  <listener>
    <listener-class>org.springframework.web.context.ContextLoaderListener</listener-class>
  </listener>

  <servlet>
    <servlet-name>LoginServlet</servlet-name>
    <servlet-class>com.hrh.web.LoginServlet</servlet-class>
  </servlet>
  <servlet-mapping>
    <servlet-name>LoginServlet</servlet-name>
    <url-pattern>/LoginServlet</url-pattern>
  </servlet-mapping>
</web-app>

WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());

获取IOC容器

package com.hrh.web;

import com.hrh.service.UserService;
import org.springframework.context.ApplicationContext;
import org.springframework.context.support.ClassPathXmlApplicationContext;
import org.springframework.web.context.support.WebApplicationContextUtils;

import javax.servlet.ServletException;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import java.io.IOException;

public class LoginServlet extends HttpServlet {
    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
            doGet(request, response);
    }

    protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {


        ApplicationContext ac = WebApplicationContextUtils.getWebApplicationContext(this.getServletContext());
        UserService userService = ac.getBean("userService", UserService.class);
        userService.login();

    }
}

Spring( 一 ) IOC

控制反转IOC

依赖注入DI

Bean的作用域

IOC容器配置 XML方法

IOC容器配置注解方式

Spring和Junit集成测试

结合WEB代码

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Spring( 一 ) IOC

控制反转IOC

依赖注入DI

Bean的作用域

IOC容器配置 XML方法

IOC容器配置 注解方式

Spring和Junit集成测试

结合WEB代码

猜你喜欢

IOC容器配置注解方式