How to solve the problem of using SpringBoot ApplicationListener event listening interface-Java Tutorial-php.cn

How to solve the problem of using SpringBoot ApplicationListener event listening interface

王林

Release： 2023-05-26 10:13:15

forward

1032 people have browsed it

Let’s reproduce the problem. Look at the code below to see if there is a problem and how to solve it:

@RequestMapping("verify")
@RestController
@DependsOn({"DingAppInfoService","CloudChatAppInfoService"})
public class LoginAction {
    @Qualifier("ElderSonService")
    @Autowired
    private ElderSonService elderSonService;
    @Qualifier("EmployeeService")
    @Autowired
    private EmployeeService employeeService;
    @Qualifier("UserThreadPoolTaskExecutor")
    @Autowired
    private ThreadPoolTaskExecutor userThreadPoolTaskExecutor;
    private static AuthRequest ding_request = null;
    private static RongCloud cloud_chat = null;
    private static TokenResult register = null;
    private static final ThreadLocal USER_TYPE = new ThreadLocal<>();
    /**
     * 注意不能在bean的生命周期方法上添注@CheckAppContext注解
     */
    @PostConstruct
    public void beforeVerifySetContext() {
        AppContext.fillLoginContext();
        Assert.hasText(AppContext.getAppLoginDingId(), "初始化app_login_ding_id错误");
        Assert.hasText(AppContext.getAppLoginDingSecret(), "初始化app_login_ding_secret错误");
        Assert.hasText(AppContext.getAppLoginReturnUrl(), "初始化app_login_return_url错误");
        Assert.hasText(AppContext.getCloudChatKey(), "初始化cloud_chat_key错误");
        Assert.hasText(AppContext.getCloudChatSecret(), "初始化cloud_chat_secret错误");
        if (!(StringUtils.hasText(AppContext.getCloudNetUri()) || StringUtils.hasText(AppContext.getCloudNetUriReserve()))) {
            throw new IllegalArgumentException("初始化cloud_net_uri与cloud_net_uri_reserve错误");
        }
        ding_request = new AuthDingTalkRequest(
                AuthConfig.builder().
                        clientId(AppContext.getAppLoginDingId()).
                        clientSecret(AppContext.getAppLoginDingSecret()).
                        redirectUri(AppContext.getAppLoginReturnUrl()).build());
        cloud_chat = RongCloud.getInstance(AppContext.getCloudChatKey(), AppContext.getCloudChatSecret());
    }
.....以下API方法无所影响......
}

Copy after login

What may be puzzling is the code of the initialization method in the controller component:

    public static void fillLoginContext() {
        DingAppInfo appInfo = SpringContextHolder.getBean(DingAppInfoService.class).findAppInfo(APP_CODE);
        setDingVerifyInfo(appInfo);
        CloudChatAppInfo cloudChatAppInfo = SpringContextHolder.getBean(CloudChatAppInfoService.class).findAppInfo(APP_CODE);
        setCloudChatInfo(cloudChatAppInfo);
    }
   public static void setDingVerifyInfo(DingAppInfo dingAppInfo){
        if (dingAppInfo.checkKeyWordIsNotNull(dingAppInfo)) {
            put(APP_LOGIN_DING_ID, dingAppInfo.getApp_id());
            put(APP_LOGIN_DING_SECRET, dingAppInfo.getApp_secret());
            put(APP_LOGIN_RETURN_URL, dingAppInfo.getApp_return_url());
        }
    }
    public static void setCloudChatInfo(CloudChatAppInfo cloudChatAppInfo){
        if (cloudChatAppInfo.checkKeyWordIsNotNull(cloudChatAppInfo)){
            put(CLOUD_CHAT_KEY,cloudChatAppInfo.getCloud_key());
            put(CLOUD_CHAT_SECRET,cloudChatAppInfo.getCloud_secret());
            put(CLOUD_NET_URI,cloudChatAppInfo.getCloud_net_uri());
            put(CLOUD_NET_URI_RESERVE,cloudChatAppInfo.getCloud_net_uri_reserve());
        }
    }

Copy after login

You can find here that actually pouring some project customized data into the local thread ThreadLocal> object of our static custom context AppContext, but we know that this type is a thread Isolated, different threads have different data, and each of our requests is a thread, which will inevitably lead to data loss, so even if we put the data in when the component is initialized, the next request will still be reported. abnormal.

Solution idea (actually this is not the solution, but it can also be done at the cost of high performance):

Design a listener and a publisher in the method of request entry Perform aspect processing. The aspect checks the AppContext object data. If it is empty, the event will be published. If it is not empty, enter the method:

Event prototype:

public class AppContextStatusEvent extends ApplicationEvent {
    public AppContextStatusEvent(Object source) {
        super(source);
    }
    public AppContextStatusEvent(Object source, Clock clock) {
        super(source, clock);
    }
}

Copy after login

Listener:

@Component
public class AppContextListener implements ApplicationListener {
    @Override
    public void onApplicationEvent(AppContextStatusEvent event) {
        if ("FillAppContext".equals(event.getSource())) {
            AppContext.fillLoginContext();
        } else if ("CheckAppContextLogin".equals(event.getSource())) {
            boolean checkContext = AppContext.checkLoginContext();
            if (!checkContext) {
                AppContext.fillLoginContext();
            }
        }
    }
}

Copy after login

Publisher (aspect class):

@Aspect
@Component("AppContextAopAutoSetting")
public class AppContextAopAutoSetting {
    @Before("@annotation(com.lww.live.ApplicationListener.CheckAppContextLogin)")
    public void CheckContextIsNull(JoinPoint joinPoint){
        System.out.println("-----------aop---------CheckAppContextLogin---------start-----");
        MethodSignature signature = (MethodSignature) joinPoint.getSignature();
        boolean value = signature.getMethod().getAnnotation(CheckAppContextLogin.class).value();
        if (value){
            boolean checkContext = AppContext.checkLoginContext();
            if (!checkContext){
                SpringContextHolder.pushEvent(new AppContextStatusEvent("FillAppContext"));
            }
        }
    }
    @After("@annotation(com.lww.live.ApplicationListener.CheckAppContextLogin)")
    public void CheckContextIsNull(){
        System.out.println("-----------aop---------CheckAppContextLogin---------end-----");
        SpringContextHolder.pushEvent(new AppContextStatusEvent("CheckAppContextLogin"));
    }
}

Copy after login

Then the AOP aspect class captures the annotation:

@Inherited
@Documented
@Target(ElementType.METHOD)
@Retention(RetentionPolicy.RUNTIME)
public @interface CheckAppContextLogin {
    boolean value() default false;
    String info() default "";
}

Copy after login

It is not difficult to find that we check first in the pre- and post-enhancement methods of the aspect. AppContext data integrity, and then fill in the data. In this way, it can be achieved if we annotate @CheckAppContextLogin on every request method. However, the problem is that other data except the filled methods are too difficult to maintain, the cost of aspect hijacking agents is too high, and the frequency of checking data is too high.

Correct solution:

Divide according to the business function of the data, because it mainly realizes the filling of two objects. Even if these data are lost, the member variables of the same controller component They are all the same object, and they are all initialized during initialization, so subsequent switching requests will not affect their ability to implement business:

 private static AuthRequest ding_request = null;
 private static RongCloud cloud_chat = null;

Copy after login

We can ask the front end to pass us the current user in the interceptor The user type and unique identifier are used to encapsulate the user-customized data for each request (to reduce the method chain library check operation called within the request):

public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
        String token = (String) request.getSession().getAttribute("token");
        String user_type = (String) request.getSession().getAttribute("user_type");
        if (StringUtils.hasText(token) && StringUtils.hasText(user_type)) {
            Context context = new Context();
            if (Objects.equals(user_type, "elder_son")) {
                ElderSon elderSon = elderSonService.getElderSonByElderSonId(token);
                context.setContextByElderSon(elderSon);
                return true;
            } else if (Objects.equals(user_type, "employee")) {
                Employee employee = employeeService.getEmployeeById(token);
                context.setContextByEmployee(employee);
                return true;
            }
        } else if (StringUtils.hasText(user_type)) {
            response.sendRedirect("/verify/login?user_type=" + user_type);
            return false;
        }
        return false;
    }

Copy after login

Finally, don’t forget to remove the ThreadLocal reference:

 @Override
    public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {
        AppContext.clear();
        HandlerInterceptor.super.afterCompletion(request, response, handler, ex);
    }

Copy after login

So the actual scenario is actually solved, the core is the business, and the code simplicity is just an incidental requirement.

The above is the detailed content of How to solve the problem of using SpringBoot ApplicationListener event listening interface. For more information, please follow other related articles on the PHP Chinese website!