day2.1.4spring ioc实现登录功能

Spring 介绍

Spring 是分层的 Java SE/EE 应用 full-stack 轻量级开源框架

• full-stack：servlet service dao

• 轻量级： 按需添加模块

• 开源：可以获取源代码

  以 IoC- （Inverse Of Control：反转控制）和 AOP- （Aspect Oriented Programming：面向切面编程）
  为内核

SpringIOC介绍：

类似于c内存分配和回收由程序员管理，java将这个过程通过jvm进行管理，程序员将主要精力用于业务逻辑的处理。程序员传统创建对象通过new来完成，而现在程序员只要在配置文件写少量代码就行，对象的创建和管理由spring来完成。

IDEA+Spring开发环境搭建：

maven导入依赖

<dependencies>
        <!--spring依赖 -->
        <dependency>
            <groupId>org.springframework</groupId>
            <artifactId>spring-context</artifactId>
            <version>5.2.9.RELEASE</version>
        </dependency>

        <!--日志包-->
        <dependency>
            <groupId>org.slf4j</groupId>
            <artifactId>slf4j-log4j12</artifactId>
            <version>1.7.25</version>
        </dependency>
        <dependency>
            <groupId>log4j</groupId>
            <artifactId>log4j</artifactId>
            <version>1.2.17</version>
        </dependency>

        <dependency>
            <groupId>junit</groupId>
            <artifactId>junit</artifactId>
            <version>4.11</version>
            <scope>test</scope>
        </dependency>
</dependencies>

开发步骤：

TestLoginService：

public class TestLoginService {
    private static final Logger logger = LoggerFactory.getLogger(TestLoginService.class);
    private ClassPathXmlApplicationContext context;
    @Before
    public void init(){
        //1:创建ioc 容器对象  暂时看成map
        context=new ClassPathXmlApplicationContext("applicationContext.xml");
        //2:给定配置文件的名称 applicationContext.xml
    }
    @Test
    public void Test01(){
        LoginService loginService = (LoginService) context.getBean("loginService");
        User user = (User) context.getBean("user");
        user.setUsername("jack");
        user.setPassword("123456");
        logger.debug(user+"");
        int res = loginService.login(user);
        if(res == -1){
            System.out.println("用户不存在");
        }else if(res == 1){
            System.out.println("登录成功");
        }else{
            System.out.println("密码错误");
        }
        logger.debug(loginService+":res="+res);
    }
}

LoginService:

@Service
public class LoginService {
    @Autowired
    @Qualifier("loginDao")
    private LoginDao loginDao;
    public int login(User user) {
        User u = loginDao.login(user);
        if (u == null) {
            return -1;
        } else if (u.getUsername().equals(user.getUsername()) && u.getPassword().equals(user.getPassword())){
            return 1;
        }else {
            return -2;
        }
    }
}

LoginDao:

@Repository
public class LoginDao {
    private User u;
    {
        u =  new User();
        u.setUsername("jack");
        u.setPassword("123456");
    }
    public User login(User user) {
        return u;
    }
}

User:

@Component
public class User {
    private String username;
    private String password;

    public User() {
    }

    public User(String username, String password) {
        this.username = username;
        this.password = password;
    }

    public String getUsername() {
        return username;
    }

    public void setUsername(String username) {
        this.username = username;
    }

    public String getPassword() {
        return password;
    }

    public void setPassword(String password) {
        this.password = password;
    }

//    @Override
//    public String toString() {
//        return "User{" +
//                "username='" + username + '\'' +
//                ", password='" + password + '\'' +
//                '}';
//    }
}

运行结果：