@Resource和@Autowired都是做bean的注入时使用，其实@Resource并不是Spring的注解，它的包是javax.annotation.Resource，需要导入，但是Spring支持该注解的注入。
Demo:
public interface Human {
String runMarathon();
}
@Service
public class Man implements Human {
@Override
public String runMarathon() {
return "man ---";
}
}
@Service
public class Woman implements Human {
@Override
public String runMarathon() {
return "woman ---";
}
}
@Service
public class TestMan {
public String runMarathon() {
return "testman ---";
}
}
使用@Resource
case1:
@RestController
@RequestMapping("/hello")
public class HelloController {
@Resource
private Human testman;
@GetMapping("/uu")
public String list() {
return testman.runMarathon();
}
}
启动spring boot直接报错：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'helloController': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.imooc.luckymoney.Human' available: expected single matching bean but found 2: man,woman
at org.springframework.context.annotation.CommonAnnotationBeanPostProcess
case2:
@RestController
@RequestMapping("/hello")
public class HelloController {
@Resource
private Human human;
@GetMapping("/uu")
public String list() {
return human.runMarathon();
}
}
启动spring boot直接报错：
org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'helloController': Injection of resource dependencies failed; nested exception is org.springframework.beans.factory.NoUniqueBeanDefinitionException: No qualifying bean of type 'com.imooc.luckymoney.Human' available: expected single matching bean but found 2: man,woman
at org.springframework.context.annotation.CommonAnnotationBeanPostProcessor.postProcessProperties(CommonAnnotationBeanPostProcessor.java:324) ~[spring-context-5.1.5.RELEASE.jar:5.1.5.RELEASE]
case3:
@RestController
@RequestMapping("/hello")
public class HelloController {
@Resource
private Human man;
@GetMapping("/uu")
public String list() {
return man.runMarathon();
}
}
输出：man--
case4:
@RestController
@RequestMapping("/hello")
public class HelloController {
@Resource
private Human man;
@GetMapping("/uu")
public String list() {
return man.runMarathon();
}
}
输出：woman--
使用@Autowired
case1:
编译直接报错
case2：
@RestController
@RequestMapping("/hello")
public class HelloController {
@Autowired
private Human man;
@GetMapping("/uu")
public String list() {
return man.runMarathon();
}
}
输出：man--
case3:
@RestController
@RequestMapping("/hello")
public class HelloController {
@Autowired
private Human woman;
@GetMapping("/uu")
public String list() {
return woman.runMarathon();
}
}
输出：woman--
case4:
