Spring-IOC是实现[03-其他实现方式]

冷不防 2022-02-18 13:17 197阅读 0赞

## Java配置方式 ##

> java配置本质上,就是一个Java类去代替xml配置。

## 1.创建java项目 ##

## 2.引入相关jar包 ##

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## 3.创建实体类 ##

## 4.创建配置文件类 ##

/**
     * 该类相当于 application.xml文件
     * 
     *
     */
    @Configuration
    public class AppJavaConfig {
    
    	/**
    	 * 该方法生成一个Book对象，和application.xml文件中的bean标签一致
    	 * 默认 id为方法名，可以通过name和value属性自定义
    	 * @return
    	 */
    	@Bean
    	public Book getBook(){
    		return new Book();
    	}
    }

## 5.测试调用 ##

@Test
    	public void test1() {
    		AnnotationConfigApplicationContext ac = 
    				new AnnotationConfigApplicationContext(AppJavaConfig.class);
    		Book book = ac.getBean(Book.class);
    		System.out.println(book);
    	}

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## 自动配置 ##

前面这种方式，对于所有要使用的类都需要一个一个的配置。而已通过自动配置来简化Bean的配置。

## xml配置 ##

xml配置通过四个注解来实现。

<table> 
 <thead> 
  <tr> 
   <th>注解</th> 
   <th>描述</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>@Component</td> 
   <td>一般用在身份不明的组件上</td> 
  </tr> 
  <tr> 
   <td>@Setvice</td> 
   <td>一般用在Service层</td> 
  </tr> 
  <tr> 
   <td>@Controller</td> 
   <td>一般用在控制层</td> 
  </tr> 
  <tr> 
   <td>@Repository</td> 
   <td>一般用在数据库访问层</td> 
  </tr> 
 </tbody> 
</table>

## 1.需要在application.xml文件中开启注解扫描 ##

## 2.java对象中添加对应的注解 ##

![在这里插入图片描述][20190417151855381.]

## 3.测试 ##

![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwOTg0NTYx_size_16_color_FFFFFF_t_70 2]

## 简单案例 ##

## 1.创建项目 ##

![在这里插入图片描述][20190417152013965.]

## 2.创建dao层 ##

package com.sxt.dao;
    
    public interface IUserDao {
    	String add(String msg);
    }

package com.sxt.dao.impl;
    
    
    import org.springframework.stereotype.Repository;
    
    import com.sxt.dao.IUserDao;
    @Repository
    public class UserDaoImpl implements IUserDao{
    	
    	@Override
    	public String add(String msg) {
    		System.out.println("----->"+msg);
    		return "hello";
    	}
    
    }

## 3.创建service层 ##

package com.sxt.service;
    
    public interface IUserService {
    	String add(String msg);
    }

package com.sxt.service.impl;
    
    import javax.annotation.Resource;
    
    
    import org.springframework.stereotype.Service;
    
    import com.sxt.dao.IUserDao;
    import com.sxt.service.IUserService;
    @Service
    public class UserServiceImpl implements IUserService{
    	@Resource
    	private IUserDao dao;
    
    	@Override
    	public String add(String msg) {
    		return dao.add(msg);
    	}
    
    }

## 4.创建Controller层 ##

package com.sxt.controller;
    
    import javax.annotation.Resource;
    
    
    import org.springframework.stereotype.Controller;
    
    import com.sxt.service.IUserService;
    @Controller
    public class UserConrtroller {
    	@Resource
    	private IUserService userService;
    	
    
    	public void add(String msg) {
    		System.out.println("-------"+userService.add(msg));
    		
    		//return userService.add(msg);
    	}
    
    }

## 5.在配置文件中添加扫描 ##

<context:component-scan 
    	base-package="com.sxt.controller,com.sxt.service.impl,com.sxt.dao.impl"/>

## 6.测试 ##

package com.sxt.test;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    import com.sxt.controller.UserConrtroller;
    
    public class Test {
    	public static void main(String[] args) {
    		ApplicationContext ac = new ClassPathXmlApplicationContext("application.xml");
    		UserConrtroller bean = ac.getBean(UserConrtroller.class);
    		bean.add("aaa");
    	}
    }

![在这里插入图片描述][20190417152645862.]

## 7.java代码配置 ##

Java配置和XML配置基本一致，唯一不同的地方就是包扫描的方式。移除application.xml

package com.sxt.test;
    
    import org.springframework.context.annotation.ComponentScan;
    import org.springframework.context.annotation.Configuration;
    @Configuration
    @ComponentScan("com.sxt.*")
    public class JavaConfig {
    
    }

## 8.测试 ##

package com.sxt.test;
    
    import org.springframework.context.ApplicationContext;
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    import com.sxt.controller.UserConrtroller;
    
    public class Test {
    	public static void main(String[] args) {
    	 ApplicationContext context = new AnnotationConfigApplicationContext(JavaConfig.class);
    	 UserConrtroller bean = context.getBean(UserConrtroller.class);
    	 bean.add("aa");
    		
    	}
    }

![在这里插入图片描述][20190417153242894.]

## @Resource和@Autowired的区别 ##

<table> 
 <thead> 
  <tr> 
   <th>注解</th> 
   <th>区别</th> 
  </tr> 
 </thead> 
 <tbody> 
  <tr> 
   <td>@Resource</td> 
   <td>1.默认根据name注入对象2.jdk提供的注解</td> 
  </tr> 
  <tr> 
   <td>@Autowired</td> 
   <td>1.只能根据类型注入对象 2.spring框架提供的注解3.需要根据name注入对象需要和@Qualifier一块使用</td> 
  </tr> 
 </tbody> 
</table>

扫描特殊配置

<context:component-scan base-package="com.itbaizhan"
    		use-default-filters="false">
    		<context:include-filter type="annotation"
    			expression="org.springframework.stereotype.Service" />
    	</context:component-scan>

> use-default-filters  
> 表示使用使用spring默认提供的过滤器，  
> false表示不使用，true则表示使用。  
> 一般来说，  
> true结合exclude-filter标签使用，表示除去某个注解  
> false结合include标签使用，表示包含某个注解

## profile ##

在实际开发中，项目即将上线时，可能需要不停的在开发环境、生产环境、测试环境…之间进行切换。

## java配置实现 ##

## 1.创建实体类 ##

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## 2.java配置文件 ##

package com.sxt;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    import org.springframework.context.annotation.Profile;
    
    import com.sxt.bean.DataSource;
    
    @Configuration
    public class JavaConfig {
    	@Bean
    	@Profile("dev")
    	public DataSource getdev(){
    		DataSource source = new DataSource();
    		source.setUrl("http://dev1:8080/");
    		source.setUsername("admin");
    		source.setPassword("123456");
    		return source;
    		
    	}
    	@Bean
    	@Profile("pro")
    	public DataSource getpro(){
    		DataSource source = new DataSource();
    		source.setUrl("http://pro:8083/");
    		source.setUsername("root");
    		source.setPassword("111");
    		return source;
    		
    	}
    
    }

## 3.测试切换 ##

package com.sxt.test;
    
    
    import org.springframework.context.annotation.AnnotationConfigApplicationContext;
    
    
    import com.sxt.JavaConfig;
    import com.sxt.bean.DataSource;
    
    
    public class Test {
    	public static void main(String[] args) {
    		AnnotationConfigApplicationContext ac = 
    				new AnnotationConfigApplicationContext();
    		// 设置环境变量信息
    		ac.getEnvironment().setActiveProfiles("pro");
    		// 注册Java配置文件
    		ac.register(JavaConfig.class);
    		// 刷新 重新加载
    		ac.refresh();
    		
    		DataSource sources = (DataSource) ac.getBean(DataSource.class);
    		System.out.println(sources);
    		
    	}
    }

![在这里插入图片描述][20190417153617321.]  
![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L3FxXzMwOTg0NTYx_size_16_color_FFFFFF_t_70 4]

## xml配置 ##

## 1.创建相关的Bean ##

## 2.在xml配置中配置bean ##

<?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"
    	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-4.3.xsd">
    	<beans profile="dev">
    		<bean class="com.sxt.bean.DataSource">
    			<property name="url" value="http://dev1:8080/"/>
    			<property name="username" value="root"/>
    			<property name="password" value="111"/>
    		</bean>
    	</beans>
    	<beans profile="pro">
    		<bean class="com.sxt.bean.DataSource">
    			<property name="url" value="http://pro:8083/"/>
    			<property name="username" value="admin"/>
    			<property name="password" value="222"/>
    		</bean>
    	</beans>
    </beans>

## 3.测试数据 ##

package com.sxt.test;
    
    import org.springframework.context.support.ClassPathXmlApplicationContext;
    
    import com.sxt.bean.DataSource;
    
    public class Test {
    	public static void main(String[] args) {
    		ClassPathXmlApplicationContext ac = new ClassPathXmlApplicationContext("application.xml");
    		ac.getEnvironment().setActiveProfiles("pro");
    		ac.refresh();
    		
    		DataSource bean = ac.getBean(DataSource.class);
    		System.out.println(bean);
    		
    	}
    }

![在这里插入图片描述][2019041715390156.]  
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