Constructor-based dependency injection（构造器注入）
@Component
2public class ConstructorBasedInjection {
3
4 private final InjectedBean injectedBean;
5
6 @Autowired
7 public ConstructorBasedInjection(InjectedBean injectedBean) {
8 this.injectedBean = injectedBean;
9 }
10
11}
Setter-based dependency injection（set 注入）
@Component
2public class ConstructorBasedInjection {
3
4 private InjectedBean injectedBean;
5
6 @Autowired
7 public void setInjectedBean(InjectedBean injectedBean) {
8 this.injectedBean = injectedBean;
9 }
10
11}
Field-based dependency injection（使用字段(Filed)注入（用注解方式））
In field-based dependency injection, fields/properties are annotated with @Autowired. Spring container will set these fields once the class is instantiated.
1@Component
2public class ConstructorBasedInjection {
3
4 @Autowired
5 private InjectedBean injectedBean;
6
7}
