springboot中设置API代码的超时时间

因为web服务本身的持久性，大多数时候超时设置应该在请求方设置；

当前一个springboot框架的web项目有一个需求，需要给api设置最大响应时间，超过这个时间，服务自动返回默认值给请求方。

现在有如下操作：

一、主线启动类加异步支持注解

package com.zving;

import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;

@SpringBootApplication
@EnableAsync public class WebApplication {

    public static void main(String[] args) {
        SpringApplication.run(WebApplication.class, args);
    }

}

二、主要的逻辑代码独立出来，放入另一个文件中，接口api异步调用该逻辑代码

package com.zving.util;

import java.util.concurrent.Future;
import org.springframework.scheduling.annotation.Async;
import org.springframework.scheduling.annotation.AsyncResult;
import org.springframework.stereotype.Component;

@Component
public class ApiUtil {

    @Async public Future<String> submitFun() throws InterruptedException {
        //业务逻辑具体代码
        Thread.sleep(4000);
        return new AsyncResult<String>("后端业务逻辑已经处理完成");    
    }
}

三、接口的线程有时间比较，超过时间则返回一个默认值

package com.zving.controller;

import java.util.concurrent.ExecutionException;
import java.util.concurrent.Future;

import javax.annotation.Resource;
import org.springframework.web.bind.annotation.GetMapping;
import org.springframework.web.bind.annotation.RestController;
import com.zving.util.ApiUtil;

@RestController
public class ApiController {

    @Resource
    private ApiUtil util;

    @GetMapping(value = "/submit")
    public String submit() throws InterruptedException, ExecutionException {
        long oldTime = System.currentTimeMillis();
        Future<String> result = util.submitFun();
        while(true) {
            long newTime = System.currentTimeMillis();
            if(result.isDone()) {
                return result.get();
            }
            if(newTime-oldTime>3000) {
                return "后端业务逻辑正在处理，请耐心等待";
            }
        }
    }
}