@Qualifier 注解作用就是为了给Bean打上一个标记，用来查找bean，代码示例:
创建一个java bean package com.gupaoedu.springcloud.example.demo; public class TestClass { private String name; // getter setter 略 } 编写配置类，将这个bean装载到IOC容器 package com.gupaoedu.springcloud.example.demo; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.context.annotation.Bean; import org.springframework.context.annotation.Configuration; @Configuration public class TestConfiguration { @Bean("testClass1") TestClass testClass1(){ return new TestClass("TestClass1"); } @Qualifier @Bean("testClass2") TestClass testClass2(){ return new TestClass("TestClass2"); } } 启动类，配置扫描包 package com.gupaoedu.springcloud.example.springclouduserservice; import org.springframework.boot.SpringApplication; import org.springframework.boot.autoconfigure.SpringBootApplication; import org.springframework.context.annotation.ComponentScan; @ComponentScan(basePackages = "com.gupaoedu") @SpringBootApplication public class SpringCloudUserServiceApplication { public static void main(String[] args) { SpringApplication.run(SpringCloudUserServiceApplication.class, args); } } 测试controller 对testClassList 加上@Qualifier注解 package com.gupaoedu.springcloud.example.demo; import org.springframework.beans.factory.annotation.Autowired; import org.springframework.beans.factory.annotation.Qualifier; import org.springframework.web.bind.annotation.GetMapping; import org.springframework.web.bind.annotation.RestController; import java.util.Collections; import java.util.List; @RestController public class TestController { @Qualifier @Autowired List<TestClass> testClassList= Collections.emptyList(); @GetMapping("/test") public Object test(){ return testClassList; } }然后启动，访问/test， 看到只打印了 TestClass2 然后对testClass1 Bean的注入，也加上@Qualifier注解后再请求/test
@Qualifier @Bean("testClass1") TestClass testClass1(){ return new TestClass("TestClass1"); }结果如下，可以看到，只有加了@Qualifier标记的Bean, 才会被注入给同样加了@Qualifier标记的 testClassList 这个list中 注： 本文是为了给ribbon负载均衡原理中， @LoadBalanced注解实现负载均衡的原理做铺垫；
