相关注解
@Autowired：spring提供注解，根据类型注入属性
@Target({ElementType.CONSTRUCTOR, ElementType.METHOD, ElementType.PARAMETER, ElementType.FIELD, ElementType.ANNOTATION_TYPE}) @Retention(RetentionPolicy.RUNTIME) @Documented public @interface Autowired { /** * Declares whether the annotated dependency is required. * <p>Defaults to {@code true}. */ boolean required() default true; }
@Qualifier：@Autowired注入时，若有多个同类型的bean，可使用该注解指定加载的bean的名称
@Target({ElementType.FIELD, ElementType.METHOD, ElementType.PARAMETER, ElementType.TYPE, ElementType.ANNOTATION_TYPE}) @Retention(RetentionPolicy.RUNTIME) @Inherited @Documented public @interface Qualifier { String value() default ""; }
@Resource：java提供注解，可根据名称（默认）、类型注入属性
@Target({ElementType.TYPE, ElementType.FIELD, ElementType.METHOD}) @Retention(RetentionPolicy.RUNTIME) @Repeatable(Resources.class) public @interface Resource { String name() default ""; //根据名称注入属性，默认使用名称注入 Class<?> type() default Object.class; //根据类型注入属性 String lookup() default ""; boolean shareable() default true; String mappedName() default ""; String description() default ""; Resource.AuthenticationType authenticationType() default Resource.AuthenticationType.CONTAINER; public static enum AuthenticationType { CONTAINER, APPLICATION; private AuthenticationType() { } } }
示例
*****************
pojo 层
Person
@Data public class Person { private String name; private Integer age; }
*****************
config 层
WebConfig
@Configuration public class WebConfig { @Bean("person") public Person initPerson(){ Person person=new Person(); person.setName("瓜田李下"); person.setAge(20); return person; } @Bean("person2") public Person initPerson2(){ Person person=new Person(); person.setName("瓜田李下 2"); person.setAge(21); return person; } }
*****************
controller 层
HelloController
@RestController public class HelloController { @Autowired @Qualifier("person") private Person person; @Autowired @Qualifier("person2") private Person person2; @RequestMapping("/hello") public String hello(){ System.out.println("helloController： "+person); System.out.println("helloController： "+person2); return "success"; } }
Hello2Controller
@RestController public class Hello2Controller { @Resource private Person person; @Resource private Person person2; @Resource(name = "person2") private Person person3; @RequestMapping("/hello2") public String hello(){ System.out.println("hello2Controller： "+person); System.out.println("hello2Controller： "+person2); System.out.println("hello2Controller： "+person3); return "success"; } }
*****************
控制台输出
localhost:8080/hello
helloController： Person(name=瓜田李下, age=20) helloController： Person(name=瓜田李下 2, age=21)
localhost:8080/hello2
hello2Controller： Person(name=瓜田李下, age=20) hello2Controller： Person(name=瓜田李下 2, age=21) hello2Controller： Person(name=瓜田李下 2, age=21)
