06. Custom interceptors, global exception handler classes, asynchronous calls

Custom interceptors

import org.springframework.context.annotation.Configuration;
import org.springframework.web.servlet.HandlerInterceptor;
import org.springframework.web.servlet.ModelAndView;
import org.springframework.web.servlet.config.annotation.InterceptorRegistry;
import org.springframework.web.servlet.config.annotation.WebMvcConfigurerAdapter;

import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;

/**
 * 自定义拦截器
 */
@Configuration
public class MyInterceptor extends WebMvcConfigurerAdapter {
    @Override
    public void addInterceptors(InterceptorRegistry registry) {
        HandlerInterceptor inter = new HandlerInterceptor() {
            @Override
            public boolean preHandle(HttpServletRequest request, HttpServletResponse response, Object handler) throws Exception {
                System.out.println("request:"+request.getRequestURL());
                return true;
            }

            @Override
            public void postHandle(HttpServletRequest request, HttpServletResponse response, Object handler, ModelAndView modelAndView) throws Exception {

            }

            @Override
            public void afterCompletion(HttpServletRequest request, HttpServletResponse response, Object handler, Exception ex) throws Exception {

            }
        };
        registry.addInterceptor(inter).addPathPatterns("/**");
    }
}

Global Exception class

import org.springframework.web.bind.annotation.ExceptionHandler;
import org.springframework.web.bind.annotation.RestControllerAdvice;

import java.util.HashMap;
import java.util.Map;

/**
 * 全局异常处理类
 */
@RestControllerAdvice
public class GlobalExceptionHandler {
    @ExceptionHandler(Exception.class)
    public Map<String,Object> handleException(Exception e){
        Map<String, Object> map = new HashMap<>();
        map.put("errorCode",500);
        map.put("errorMsg",e.toString());
        return map;
    }
}

Asynchronous call

@SpringBootApplication(scanBasePackages = {"com.fly"})
@EnableAsync
public class SpringDemoApp{

import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Service;

import java.util.Random;
import java.util.concurrent.Future;

@Service
public class AsyncServiceImpl {
    private static Random random = new Random();

    @Async
    public Future<String> doTask1() throws Exception{
        System.out.println("doTask1 start");
        long b = System.currentTimeMillis();
        Thread.sleep(random.nextInt(1000));
        long e = System.currentTimeMillis();
        System.out.println("doTask1 end:"+(e-b));
        return new AsyncResult<>("doTask1 end");
    }

    @Async
    public Future<String> doTask2() throws Exception{
        System.out.println("doTask2 start");
        long b = System.currentTimeMillis();
        Thread.sleep(random.nextInt(1000));
        long e = System.currentTimeMillis();
        System.out.println("doTask2 end:"+(e-b));
        return new AsyncResult<>("doTask2 end");
    }

    @Async
    public Future<String> doTask3() throws Exception{
        System.out.println("doTask3 start");
        long b = System.currentTimeMillis();
        Thread.sleep(random.nextInt(1000));
        long e = System.currentTimeMillis();
        System.out.println("doTask3 end:"+(e-b));
        return new AsyncResult<>("doTask3 end");
    }
}

 @Autowired
    private AsyncServiceImpl asyncService;

    @RequestMapping("/asyn")
    public String asyn() throws Exception {
        long b = System.currentTimeMillis();
        Future<String> f1 = asyncService.doTask1();
        Future<String> f2 = asyncService.doTask2();
        Future<String> f3 = asyncService.doTask3();
        while (true){
            if (f1.isDone()&&f2.isDone()&&f3.isDone()){
                break;
            }
        }
        long e = System.currentTimeMillis();
        return "asyn end:"+(e-b);
        //doTask2 start
        //doTask1 start
        //doTask3 start
        //doTask1 end:290
        //doTask2 end:607
        //doTask3 end:795

        //"asyn end:802"
    }