@Value注释失效

一、@Value的注意事项

1.不能作用于静态变量(static);

2.不能作用于常量(final);

3.不能在非注册的类中使用(类需要被注册在spring上下文中,如用@Service,@RestController,@Component等);

4.使用这个类时,只能通过依赖注入的方式,用new的方式是不会自动注入这些配置的。

/**
 * 抽象工厂+反射
 */
//不能在非注册的类中使用(类需要被注册在spring上下文中,如用@Service,@RestController,@Component等);
public class SimpleAbstractFactory  {
 
 
    @Value("${packName}")
    //不能作用于静态变量(static)
    private static String packName;
    @Value("${sqlName}")
    //不能作用于常量(final);
    private final String sqlName;
    public IUser CreateUser() throws Exception{
            String className=packName+"."+sqlName+"IUser";
            return (IUser)Class.forName(className).newInstance();
    }
 
 
    public IDepartment CreateDepartment() throws Exception{
            String className=packName+"."+sqlName+"IDepartment";
            return (IDepartment)Class.forName(className).newInstance();
    }
 
 
 
 
}
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:spring-config.xml"})
public class MainToken{
 
    @Test
	public void testToken() {
		try{
            //使用这个类时,只能通过依赖注入的方式,用new的方式是不会自动注入这些配置的。
			SimpleAbstractFactory  simpleAbstractFactory=new SimpleAbstractFactory();
			User user=new User();
			Department department=new Department();
			IDepartment idp=simpleAbstractFactory.CreateDepartment();
			IUser ius=simpleAbstractFactory.CreateUser();
			idp.insert(department);
			idp.getDepartment(Long.valueOf(1));
			ius.insert(user);
			ius.getUser(Long.valueOf(1));
		}catch(Exception e){
 
		}
	}
}
三、正确的方式
/**
 * 抽象工厂+反射
 */
@Service
public class SimpleAbstractFactory  {
 
 
    @Value("${packName}")
    private String packName;
    @Value("${sqlName}")
    private String sqlName;
    public IUser CreateUser() throws Exception{
            String className=packName+"."+sqlName+"IUser";
            return (IUser)Class.forName(className).newInstance();
    }
 
 
    public IDepartment CreateDepartment() throws Exception{
            String className=packName+"."+sqlName+"IDepartment";
            return (IDepartment)Class.forName(className).newInstance();
    }
    
}
@RunWith(SpringJUnit4ClassRunner.class)
@ContextConfiguration(locations = {"classpath:spring-config.xml"})
public class MainToken {
    @Autowired
	//使用这个类时,只能通过依赖注入的方式,用new的方式是不会自动注入这些配置的。
	private SimpleAbstractFactory simpleAbstractFactory;
    @Test
	public void testToken() {
		try{
			User user=new User();
			Department department=new Department();
			IDepartment idp=simpleAbstractFactory.CreateDepartment();
			IUser ius=simpleAbstractFactory.CreateUser();
			idp.insert(department);
			idp.getDepartment(Long.valueOf(1));
			ius.insert(user);
			ius.getUser(Long.valueOf(1));
		}catch(Exception e){
 
		}
	}
}
 

  

posted @ 2020-09-27 15:11  逝年的我们  阅读(613)  评论(0编辑  收藏  举报