简单的Spring容器注入和三种依赖注入(二)

2、属性注入

一个接口UserService.java

public interface UserService {public void add();}

一个实现类UserServiceImpl.java

public class UserServiceImpl implements UserService {@Overridepublic void add() {System.out.println("this is add()");}}

一个业务类UserAction.java

public class UserAction {private UserService userService;public void setUserService(UserService userService) {this.userService = userService;}public void say(){userService.add();}}

一个测试类：

public class Test {/** * @param args */public static void main(String[] args) {UserService userService = new UserServiceImpl();UserAction userAction = new UserAction();userAction.setUserService(userService);userAction.say();}}

3、接口注入

接口UserService.java

public interface UserService {public void add();}

实现类UserServiceImpl.java

public class UserServiceImpl implements UserService {@Overridepublic void add() {System.out.println("this is add()");}}

借助额外的一个接口

public interface InterfaceUtil { public void injectUserService(UserService userService);}

业务类

public class UserAction implements InterfaceUtil {private UserService userService;@Overridepublic void injectUserService(UserService userService) {this.userService = userService;}public void say(){userService.add();}}

测试类

public class Test {/** * @param args */public static void main(String[] args) {UserService userService = new UserServiceImpl();UserAction userAction = new UserAction();userAction.injectUserService(userService);userAction.say();}}