spring boot: scope (一般注入说明(一) @Autowired注解)

实例一：

DiConfig 文件：

package di;
import org.springframework.context.annotation.ComponentScan;
import org.springframework.context.annotation.Configuration;

//声明当前类是一个配置类
@Configuration
//自动扫描包下的所有@Service,@Component,@Repository和@Controller注册为Bean;
@ComponentScan("di")

public class DiConfig {	
	
	
}

　　

DFunctionService 文件：
@service相当于 singleton的scope

package di;
import org.springframework.stereotype.Service;

//注入：当前类是spring管理的一个bean
//相当于singleton的scope
@Service
public class DFunctionService {

	public String SayHello(String word)
	{
		return "Hello, " + word + " !";
	}
	
}

　　

 UseFunctionService 文件：

package di;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;

//注入：当前类是spring管理的一个bean
@Service
public class UseFunctionService {
	
	//将DFunctionService类的实体Bean注入到UseFunctionService中,让UseFunctionService拥有DFunctionService的功能
	//等效注解: @Autowire=@Inject=@Resource
	@Autowired
	DFunctionService functionService;
	
	public String SayHello(String word)
	{		
		return functionService.SayHello(word);
	}
	
}

　　

Main 文件：

package di;
import org.springframework.context.annotation.AnnotationConfigApplicationContext;
public class Main {

	public static void main(String args[])
	{
		
		AnnotationConfigApplicationContext context = new AnnotationConfigApplicationContext(DiConfig.class);
		UseFunctionService userFunctionService = context.getBean(UseFunctionService.class);
		System.out.print(userFunctionService.SayHello("word"));
		context.close();
				
	}
	
}

　　

运行Main.java ,结果为 hello word