springboot学习:自动装配

灰太狼 2023-05-29 05:07 16阅读 0赞

### 1、@Autowired ###

> 自动注入  
> 默认优先按照类型去容器找对应的组件:applicationContext.getBean(Dao.class);  
> 如果找到多个相同类型的组件,再将属性的名称作为组件的id去容器查找  
> applicationContext.getBean(“dao”);  
> 自动装配默认一定要将属性赋值好,没有就会报错  
> 可以使用@Autowired(required = false)来避免

*  MainConfigOfAutoWired类

@Configuration
    @ComponentScan({"com.dav.dao","com.dav.service","com.dav.controller"})
    public class MainConfigOfAutoWired {
    }

*  IOCTest\_Autowired类

public class IOCTest_Autowired {
    	@Test
    	public void test1() {
    		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(MainConfigOfAutoWired.class);
    		System.out.println("容器初始化");
    		Service service = context.getBean(Service.class);
    		System.out.println(service.toString());
    		Dao dao = context.getBean(Dao.class);
    		System.out.println(dao.toString());
    		context.close();
    	}
    }

![在这里插入图片描述][2019110414080584.png]

*  Controller 类

public class Controller {
    	@Autowired
    	private Service service;
    }

*  Service 类

@Service
    public class Service {
    	@Autowired
    	private Dao dao;	
    }

*  Dao 类

@Repository
    public class Dao {
    }

### 2、@Qualifier ###

> 使用@Qualifier指定需要装配的组件id,而不是使用属性名

*  MainConfigOfAutoWired

@Configuration
    @ComponentScan({"com.dav.dao","com.dav.service","com.dav.controller"})
    public class MainConfigOfAutoWired {
    	@Bean("dao2")
    	public Dao dao() {
    		Dao dao2 = new Dao();
    		dao2.setId(2);
    		return dao2;
    	}
    }

![在这里插入图片描述][20191104141214365.png]

*  Service

public class Service {
    	@Qualifier("dao2")
    	@Autowired
    	private Dao dao;
    	public void print() {
    		System.out.println(dao);
    	}
    	@Override
    	public String toString() {
    		return "Service [dao=" + dao + "]";
    	}
    }

*  Dao

@Repository
    public class Dao {
    	private int id = 1;
    	public int getId() {
    		return id;
    	}
    	public void setId(int id) {
    		this.id = id;
    	}
    	@Override
    	public String toString() {
    		return "Dao [id=" + id + "]";
    	}
    }

### 3、@Primary ###

> 让spring进行自动装配的时候，默认首选的bean  
> 也可以继续使用@Qualifier注定需要装配的bean

*  Dao

@Repository
    @Primary
    // 注入时默认该bean
    public class Dao {
    	private int id = 1;
    	public int getId() {
    		return id;
    	}
    	public void setId(int id) {
    		this.id = id;
    	}
    	@Override
    	public String toString() {
    		return "Dao [id=" + id + "]";
    	}
    }

*  Service

@org.springframework.stereotype.Service
    public class Service {
    	// 指定注入dao2
    //	@Qualifier("dao2")
    	@Autowired
    	private Dao dao;
    	public void print() {
    		System.out.println(dao);
    	}
    	@Override
    	public String toString() {
    		return "Service [dao=" + dao + "]";
    	}
    }

![在这里插入图片描述][2019110414171853.png]

### 4、@Resource(JSR250)和@Inject(JSR330)\[java规范注解\] ###

> @Resource：和@Autowired一样  
> @InJect：需要导入Javax.Inject包,和@Autowired一样,没有rquired=false的功能

*  TestDao 类

@Repository
    public class TestDao {
    }

*  Service 类

public class Service {
    	@Inject
    	private Dao dao;
    	@Resource
    	private TestDao testDao;
    	public void print() {
    		System.out.println(dao);
    	}
    	@Override
    	public String toString() {
    		return "Service [dao=" + dao + ", testDao=" + testDao + "]";
    	}	
    }

![在这里插入图片描述][20191106123805633.png]

### 5、@Profile ###

> Spring为我们提供的可以根据当前环境，动态的激活和切换一系列组件的功能;  
> @Profile：指定组件在哪个环境的情况下才能被注册到容器中，不指定，任何环境下都能注册这个组件  
> 1)、加了环境标识的bean，只有这个环境被激活的时候才能注册到容器中，默认是default环境  
> 2)、写在配置类上，只有是指定的环境的时候，整个配置类才能生效  
> 3)、没有标注环境标识的bean在任何环境下都是加载的

*  MainConfigOfPorfile 类

@Configuration
    public class MainConfigOfPorfile {
    	@Profile("test")
    	@Bean("testDataSource")
    	public DataSource dataSourceTest () throws PropertyVetoException {
    		ComboPooledDataSource dataSource = new ComboPooledDataSource();
    		dataSource.setUser("root");
    		dataSource.setPassword("liaowei123");
    		dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test");
    		dataSource.setDriverClass("com.mysql.jdbc.Driver");
    		return dataSource;
    	}
    	@Profile("dev")
    	@Bean("devDataSource")
    	public DataSource dataSourceDev () throws PropertyVetoException {
    		ComboPooledDataSource dataSource = new ComboPooledDataSource();
    		dataSource.setUser("root");
    		dataSource.setPassword("liaowei123");
    		dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test");
    		dataSource.setDriverClass("com.mysql.jdbc.Driver");
    		return dataSource;
    	}
    	@Profile("uat")
    	@Bean("uatDataSource")
    	public DataSource dataSourceUat () throws PropertyVetoException {
    		ComboPooledDataSource dataSource = new ComboPooledDataSource();
    		dataSource.setUser("root");
    		dataSource.setPassword("liaowei123");
    		dataSource.setJdbcUrl("jdbc:mysql://localhost:3306/test");
    		dataSource.setDriverClass("com.mysql.jdbc.Driver");
    		return dataSource;
    	}
    }

#### 5.1、使用命令行参数 ####

*  IOCTest\_Profile 类

@Test
    public void test1() {
    	AnnotationConfigApplicationContext context = 
    			new AnnotationConfigApplicationContext(MainConfigOfPorfile.class);
    
    	System.out.println("容器初始化");	
    	String[] names = context.getBeanNamesForType(DataSource.class);
    	for(String name : names) {
    		System.out.println(name);
    	}
    	context.close();
    }

> \-Dspring.profiles.active=dev(环境标识)  
> ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x3MzA1OTkzODk3_size_16_color_FFFFFF_t_70]  
> ![在这里插入图片描述][watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x3MzA1OTkzODk3_size_16_color_FFFFFF_t_70 1]

#### 5.2、使用代码激活环境 ####

*  IOCTest\_Profile 类

@Test
    public void test1() {
    	AnnotationConfigApplicationContext context = 
    			new AnnotationConfigApplicationContext();
    	// 1、创建容器对象
    	// 2、设置环境
    	// 3、注册主配置类
    	// 4、启动刷新容器
    	context.getEnvironment().setActiveProfiles("test", "dev");
    	context.register(MainConfigOfPorfile.class);
    	context.refresh();
    	System.out.println("容器初始化");	
    	String[] names = context.getBeanNamesForType(DataSource.class);
    	for(String name : names) {
    		System.out.println(name);
    	}
    	context.close();
    }

![在这里插入图片描述][20191106124456617.png]

[2019110414080584.png]: https://img-blog.csdnimg.cn/2019110414080584.png
[20191104141214365.png]: https://img-blog.csdnimg.cn/20191104141214365.png
[2019110414171853.png]: https://img-blog.csdnimg.cn/2019110414171853.png
[20191106123805633.png]: https://img-blog.csdnimg.cn/20191106123805633.png
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x3MzA1OTkzODk3_size_16_color_FFFFFF_t_70]: https://img-blog.csdnimg.cn/20191106124309270.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x3MzA1OTkzODk3,size_16,color_FFFFFF,t_70
[watermark_type_ZmFuZ3poZW5naGVpdGk_shadow_10_text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x3MzA1OTkzODk3_size_16_color_FFFFFF_t_70 1]: https://img-blog.csdnimg.cn/20191106124351667.png?x-oss-process=image/watermark,type_ZmFuZ3poZW5naGVpdGk,shadow_10,text_aHR0cHM6Ly9ibG9nLmNzZG4ubmV0L2x3MzA1OTkzODk3,size_16,color_FFFFFF,t_70
[20191106124456617.png]: https://img-blog.csdnimg.cn/20191106124456617.png