SpringBoot Basics - Interceptors

Create project

Create a Spring Boot project

 The overall project is as follows:

①Create database, table; insert data

CREATE TABLE `user` (
  `id` bigint(20) NOT NULL AUTO_INCREMENT,
  `name` varchar(255) DEFAULT NULL COMMENT '名字',
  `balance` double(255,0) DEFAULT NULL COMMENT '余额',
  `username` varchar(255) DEFAULT NULL,
  `password` varchar(255) DEFAULT NULL,
  PRIMARY KEY (`id`)
) ENGINE=InnoDB AUTO_INCREMENT=4 DEFAULT CHARSET=utf8 COMMENT='用户测试表';

configuration database 

spring:
  datasource:
    url: jdbc:mysql://localhost:3306/springboot_demo?useUnicode=true&characterEncoding=utf-8&serverTimezone=UTC
    username: root
    password: 密码
    driver-class-name: com.mysql.cj.jdbc.Driver
mybatis-plus:
  configuration:
    log-impl: org.apache.ibatis.logging.stdout.StdOutImpl
  typeAliasesPackage: com.qcby.entity
  mapperLocations: classpath:mapper/*.xml
  # 全局配置id自增  =>
  global-config:
    db-config:
      id-type: auto

 ②Create config.MybatisPlusConfig class and introduce mybatis-plus

@Configuration
public class MybatisPlusConfig {
    // 最新版
    @Bean  // <bean id=""/>
    public MybatisPlusInterceptor mybatisPlusInterceptor() {
        MybatisPlusInterceptor interceptor = new MybatisPlusInterceptor();
        interceptor.addInnerInterceptor(new PaginationInnerInterceptor(DbType.MYSQL));
        return interceptor;
    }
}

③pow.xml refresh dependency, add mybatis-plus dependency

        <!--mybatis-plus核心-->
        <dependency>
            <groupId>com.baomidou</groupId>
            <artifactId>mybatis-plus-boot-starter</artifactId>
            <version>3.4.2</version>
        </dependency>
        <dependency>
            <groupId>mysql</groupId>
            <artifactId>mysql-connector-java</artifactId>
            <scope>runtime</scope>
        </dependency>

④Create a User entity class in the entity package

//Lombok提供的注解
@Data
@TableName("user")
public class User {
    private Long id;
    private String name;
    private String balance;
    private String username;
    private String password;
}

 ⑤Create mapper.UserMapper interface

public interface UserMapper extends BaseMapper<User> {
   
}

⑥Create service.UserService interface

public interface UserService extends IService<User> {
    
}

⑦Create service.impl.UserServiceImpl class

@Service
public class UserServiceImpl extends ServiceImpl<UserMapper,User> implements UserService {
    @Resource
    private UserMapper userMapper;
}

⑧ Create controller.UserController class

@RestController
@RequestMapping("login")
public class UserController {
    @Autowired
    private UserServiceImpl service;
}

session mode

①Create config.WebMvcConfig class, inherit WebMvcConfigurer, add @Configuration annotation

@Configuration
public class WebMvcConfig implements WebMvcConfigurer {

    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        registry.addInterceptor(loginInterceptor())
                //拦截的路径(*所有)
                .addPathPatterns("/**")
                // 那些路径不拦截
                .excludePathPatterns("/login/**","/error");
    }

    @Bean
    public LoginInterceptor loginInterceptor(){
        return new LoginInterceptor();
    }
}

②Create UserController class

@RestController
@RequestMapping("login")
public class UserController {
    @Autowired
    private UserServiceImpl service;
    @Autowired
    private HttpSession session;

    @RequestMapping(value = "login",method = RequestMethod.GET)
    public Map<String,Object> login(User user){
        Map<String,Object> map = new HashMap<>();
        map.put("code",0);
        if(StringUtils.isEmpty(user.getUsername()) || StringUtils.isEmpty(user.getPassword()) ){
            map.put("msg","用户或者密码为空！");
            return map;
        }
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("username",user.getUsername())
                .eq("password",user.getPassword());
        User userDb = service.getOne(queryWrapper);
        if(userDb != null){
            map.put("code",1);
            map.put("data",userDb);
            //重点在这里
            session.setAttribute("username",userDb.getUsername());

        }else{
            map.put("msg","用户名或密码错误！");
        }
        return map;
    }

    //退出
    @RequestMapping("logout")
    public String logout(){
        session.removeAttribute("username");
        return "login";
    }
}

③Create the interceptor.LogIninterceptor class and implement the HandlerInterceptor interface

public class LoginInterceptor implements HandlerInterceptor {

    private Logger log = LoggerFactory.getLogger(getClass());

    @Autowired
    private HttpSession httpSession;

    //Controller逻辑执行之前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle....");
        String uri = request.getRequestURI();
        System.out.println("uri："+ uri);

        if (!(handler instanceof HandlerMethod)) {
            return true;
        }
        //与Session呼应
        //重点
        if (httpSession.getAttribute("username") == null) {
            // 未登录跳转到登录界面
            response.sendRedirect("/login/login");
            return false;
        } else {
            return true;
        }
       
    }
    //Controller逻辑执行完毕但是视图解析器还未进行解析之前
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle....");
    }

    //Controller逻辑和视图解析器执行完毕
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("afterCompletion....");
    }

④Test: Create Test class

@RestController
@RequestMapping("test")
public class Test {
    @RequestMapping("getInfo")
    public List<User> getInfo(HttpServletRequest request){
        return service.list();
    }
}

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token method 

①Continue to use the WebMvcConfig class

②Create token.TokenUtil class

public class TokenUtil {
    private static Map<String, User> tokenMap=new HashMap<>();

    public static String generateToken(User user){
        String token= UUID.randomUUID().toString();
        tokenMap.put(token,user);
        return token;
    }

    public static boolean verify(String token){
        return tokenMap.containsKey(token);
    }

    public static User getUser(String token){
        return tokenMap.get(token);
    }
}

③ Edit the UserController class and only modify the session part

@RestController
@RequestMapping("login")
public class UserController {
    @Autowired
    private UserServiceImpl service;
    @Autowired
    private HttpSession session;


    @ApiOperation("登录接口")
    @RequestMapping(value = "login",method = RequestMethod.GET)
    public Map<String,Object> login(User user){
        Map<String,Object> map = new HashMap<>();
        map.put("code",0);
        if(StringUtils.isEmpty(user.getUsername()) || StringUtils.isEmpty(user.getPassword()) ){
            map.put("msg","用户或者密码为空！");
            return map;
        }
        QueryWrapper<User> queryWrapper = new QueryWrapper<>();
        queryWrapper.eq("username",user.getUsername())
                .eq("password",user.getPassword());
        User userDb = service.getOne(queryWrapper);
        if(userDb != null){
            map.put("code",1);
            map.put("data",userDb);
            //session.setAttribute("username",userDb.getUsername());
            //重点
            String token= TokenUtil.generateToken(userDb);
            map.put("qcby-token",token);

        }else{
            map.put("msg","用户名或密码错误！");
        }
        return map;
    }
}

④Modify the LoginInterceptor class

public class LoginInterceptor implements HandlerInterceptor {

    private Logger log = LoggerFactory.getLogger(getClass());

    @Autowired
    private HttpSession httpSession;


    //Controller逻辑执行之前
    @Override
    public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        System.out.println("preHandle....");
        String uri = request.getRequestURI();
        System.out.println("uri："+ uri);
        if (!(handler instanceof HandlerMethod)) {
            return true;
        }
        String token=request.getHeader("qcby-token");
        if (!TokenUtil.verify(token)) {
            // 未登录跳转到登录界面
            response.sendRedirect("/login/login");
            return false;
        }else {
            return true;
        }
    }

    //Controller逻辑执行完毕但是视图解析器还未进行解析之前
    @Override
    public void postHandle(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, ModelAndView modelAndView) throws Exception {
        System.out.println("postHandle....");
    }

    //Controller逻辑和视图解析器执行完毕
    @Override
    public void afterCompletion(HttpServletRequest httpServletRequest, HttpServletResponse httpServletResponse, Object o, Exception e) throws Exception {
        System.out.println("afterCompletion....");
    }
}

⑤ Test ( postman test )

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