spring5入门（十）：基于注解管理bean，注入属性

• @Autowired：根据属性类型进行自动装配

# bean.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.ychen"></context:component-scan>

</beans>

# 持久层接口
public interface UserDao {

    public void add();

}

# 持久层实现
@Repository
public class UserDaoImpl implements UserDao {

    @Override
    public void add() {
        System.out.println("dao add.....");
    }

}

# 业务层
@Service
public class UserService {

    @Autowired
    private UserDao userDao;

    public void add() {
        System.out.println("service add.......");
        userDao.add();
    }

}

# 测试方法
public class Test3 {

    @Test
    public void testAdd() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean7.xml");
        UserService userService = context.getBean("userService", UserService.class);
        System.out.println(userService);
        userService.add();
    }

}

# 控制台
com.ychen.spring.ser.UserService@37911f88
service add.......
dao add.....

Process finished with exit code 0

• @Qualifier：根据名称进行注入，需配合@Autowired一起使用

# bean.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.ychen"></context:component-scan>

</beans>

# 持久层接口
public interface UserDao {

    public void add();

}

# 持久层实现
@Repository(value = "userDaoImpl1")
public class UserDaoImpl implements UserDao {

    @Override
    public void add() {
        System.out.println("dao add.....");
    }

}

# 业务层
@Service
public class UserService {

    @Autowired
    @Qualifier(value = "userDaoImpl1")
    private UserDao userDao;

    public void add() {
        System.out.println("service add.......");
        userDao.add();
    }

}

# 测试方法
public class Test3 {

    @Test
    public void testAdd() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean7.xml");
        UserService userService = context.getBean("userService", UserService.class);
        System.out.println(userService);
        userService.add();
    }

}

# 控制台
com.ychen.spring.ser.UserService@37911f88
service add.......
dao add.....

Process finished with exit code 0

• @Resource：可以根据类型注入，可以根据名称注入，该注解并不时spring提供的注解，只是java扩展包中的注解

## 测试一：根据类型注入
# bean.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.ychen"></context:component-scan>

</beans>

# 持久层接口
public interface UserDao {

    public void add();

}

# 持久层实现
@Repository(value = "userDaoImpl1")
public class UserDaoImpl implements UserDao {

    @Override
    public void add() {
        System.out.println("dao add.....");
    }

}

# 业务层
@Service
public class UserService {

    @Resource
    private UserDao userDao;

    public void add() {
        System.out.println("service add.......");
        userDao.add();
    }

}

# 测试方法
public class Test3 {

    @Test
    public void testAdd() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean7.xml");
        UserService userService = context.getBean("userService", UserService.class);
        System.out.println(userService);
        userService.add();
    }

}

# 控制台
com.ychen.spring.ser.UserService@37911f88
service add.......
dao add.....

Process finished with exit code 0

## 测试二：根据名称注入
# bean.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.ychen"></context:component-scan>

</beans>

# 持久层接口
public interface UserDao {

    public void add();

}

# 持久层实现
@Repository(value = "userDaoImpl1")
public class UserDaoImpl implements UserDao {

    @Override
    public void add() {
        System.out.println("dao add.....");
    }

}

# 业务层
@Service
public class UserService {

    @Resource(name = "userDaoImpl1")
    private UserDao userDao;

    public void add() {
        System.out.println("service add.......");
        userDao.add();
    }

}

# 测试方法
public class Test3 {

    @Test
    public void testAdd() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean7.xml");
        UserService userService = context.getBean("userService", UserService.class);
        System.out.println(userService);
        userService.add();
    }

}

# 控制台
com.ychen.spring.ser.UserService@37911f88
service add.......
dao add.....

Process finished with exit code 0

• @Value：注入普通类型属性

# bean.xml
<?xml version="1.0" encoding="UTF-8"?>
<beans xmlns="http://www.springframework.org/schema/beans"
       xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance"
       xmlns:context="http://www.springframework.org/schema/context"
       xsi:schemaLocation="http://www.springframework.org/schema/beans http://www.springframework.org/schema/beans/spring-beans.xsd
                           http://www.springframework.org/schema/context http://www.springframework.org/schema/context/spring-context.xsd">

    <context:component-scan base-package="com.ychen"></context:component-scan>

</beans>

# 持久层接口
public interface UserDao {

    public void add();

}

# 持久层实现类
@Repository
public class UserDaoImpl implements UserDao {

    @Override
    public void add() {
        System.out.println("dao add.....");
    }

}

# 业务层
@Service
public class UserService {

    @Value(value = "abc")
    private String name;

    @Autowired
    private UserDao userDao;

    public void add() {
        System.out.println("service add......." + name);
        userDao.add();
    }

}

# 测试方法
public class Test3 {

    @Test
    public void testAdd() {
        ApplicationContext context = new ClassPathXmlApplicationContext("bean7.xml");
        UserService userService = context.getBean("userService", UserService.class);
        System.out.println(userService);
        userService.add();
    }

}

# 控制层
com.ychen.spring.ser.UserService@2cb2fc20
service add.......abc
dao add.....

Process finished with exit code 0

• 纯注解开发

# 编写配置类
@Configuration
@ComponentScan(basePackages = {"com.ychen"})
public class SpringConfig {

}

# 编写测试方法
    @Test
    public void testService2() {
        ApplicationContext context
                = new AnnotationConfigApplicationContext(SpringConfig.class);
        UserService userService = context.getBean("userService", UserService.class);
        System.out.println(userService);
        userService.add();
    }

# 控制台
com.ychen.spring.ser.UserService@7975d1d8
service add.......abc
dao add.....

Process finished with exit code 0