Spring: Qualifier

电玩女神 2022-12-14 13:52 138阅读 0赞

用于限定注入bean的特殊用法  
1.定义注解

package tju.HclEurekaServer.anno;
    
    import java.lang.annotation.Retention;
    import java.lang.annotation.*;
    
    import org.springframework.beans.factory.annotation.Qualifier;
    
    @Retention(RetentionPolicy.RUNTIME)
    @Qualifier
    public @interface MyLoadBalanced {
    
    }

2.配置bean

package tju.HclEurekaServer.controller;
    
    import org.springframework.context.annotation.Bean;
    import org.springframework.web.bind.annotation.RequestMapping;
    import org.springframework.web.bind.annotation.RestController;
    
    import tju.HclEurekaServer.UserInfo;
    import tju.HclEurekaServer.anno.MyLoadBalanced;
    
    @RestController
    public class MyController1 {
    	
    	@Bean
    	//@MyLoadBalanced
    	UserInfo getUserInfo()
    	{
    	  UserInfo u=new UserInfo();
    	  u.setPassword("pwd");
    	  u.setUsername("yonghu");
    	  return u;
    	}
    	
    	
    	@Bean
    	@MyLoadBalanced
    	UserInfo getUserInfo2()
    	{
    	  UserInfo u=new UserInfo();
    	  u.setPassword("amadeus");
    	  u.setUsername("liu");
    	  return u;
    	}
    	
    	
    	@Bean
    	@MyLoadBalanced
    	UserInfo getUserInfo3()
    	{
    	  UserInfo u=new UserInfo();
    	  u.setPassword("david");
    	  u.setUsername("beckham");
    	  return u;
    	}
    	
    	
    	@Bean
    	@MyLoadBalanced
    	UserInfo getUserInfo4()
    	{
    	  UserInfo u=new UserInfo();
    	  u.setPassword("ryn");
    	  u.setUsername("giggs");
    	  return u;
    	}
    	
    	
    	@Bean
    	@MyLoadBalanced
    	UserInfo getUserInfo5()
    	{
    	  UserInfo u=new UserInfo();
    	  u.setPassword("crysti");
    	  u.setUsername("ronaldo");
    	  return u;
    	}
    	
    	
    	@RequestMapping("/hello")
    	public String test()
    	{
    		return "hello,wd";
    	}
    
    }

1.  注入 bean

package tju.HclEurekaServer.config;
    
    import java.util.List;
    
    import org.springframework.beans.factory.annotation.Autowired;
    import org.springframework.context.annotation.Bean;
    import org.springframework.context.annotation.Configuration;
    
    import tju.HclEurekaServer.UserInfo;
    import tju.HclEurekaServer.anno.MyLoadBalanced;
    
    @Configuration
    public class MyConfig {
    	
    	@Autowired(required=false)
    	@MyLoadBalanced
    	private List<UserInfo> userInfoList=null;
    	
    	@Bean
    	public String tt()
    	{
    		for(UserInfo u:userInfoList)
    		{
    			System.out.println(u);
    		}
    		return "good";
    	}
    
    
    }

注入ben时指定了注解，因此，在定义bean时，只有包含上述注解的bean才会被注入