SpringBoot 异步 controller 示例

下面的示例是在 springboot 的 controller 中整合异步service调用的示例。

我们需要完成：

1. 做一个提供测试测试数据的 controller。
2. 创建一个异步的 service，远程调用上面的测试数据 controller。
3. 创建一个 controller，调用多个异步 service，并等待异步调用全部完成，输出结果。

示例

1. 测试数据 controller

package com.example.demoasync;

import java.util.ArrayList;
import java.util.List;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class EmployeeDataController {
    private static Logger log = LoggerFactory.getLogger(EmployeeDataController.class);

    @RequestMapping(value = "/addresses", method = RequestMethod.GET)
    public List<String> getAddresses() {
        log.info("get addresses Start");

        ArrayList<String> employeeAddresses = new ArrayList<String>();
        employeeAddresses.add("addr1");
        employeeAddresses.add("addr2");
        employeeAddresses.add("addr3");

        return employeeAddresses;
    }

    @RequestMapping(value = "/phones", method = RequestMethod.GET)
    public List<String> getPhoneNumbers() {
        log.info("get phones Start");

        ArrayList<String> phoneNumberList = new ArrayList<String>();

        phoneNumberList.add("100000");
        phoneNumberList.add("200000");

        return phoneNumberList;
    }

    @RequestMapping(value = "/names", method = RequestMethod.GET)
    public List<String> getEmployeeName() {
        log.info("get names Start");

        List<String> employeeList = new ArrayList<String>();

        employeeList.add("Santa");
        employeeList.add("Banta");

        return employeeList;
    }
}

2. 异步 service

package com.example.demoasync;

import java.util.List;
import java.util.concurrent.CompletableFuture;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.context.annotation.Bean;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import org.springframework.web.client.RestTemplate;

@Service
public class AsyncService {

    private static Logger log = LoggerFactory.getLogger(AsyncService.class);

    @Autowired
    private RestTemplate restTemplate;

    @Bean
    public RestTemplate restTemplate() {
        return new RestTemplate();
    }

    @Async("asyncExecutor")
    public CompletableFuture<List<String>> getEmployeeName() throws InterruptedException {
        log.info("getEmployeeName starts");

        List<String> employeeNameData = restTemplate.getForObject("http://localhost:8080/names", List.class);

        log.info("employeeNameData, {}", employeeNameData);
        Thread.sleep(1000L); // Intentional delay
        log.info("employeeNameData completed");
        return CompletableFuture.completedFuture(employeeNameData);
    }

    @Async("asyncExecutor")
    public CompletableFuture<List<String>> getEmployeeAddress() throws InterruptedException {
        log.info("getEmployeeAddress starts");

        List<String> employeeAddressData = restTemplate.getForObject("http://localhost:8080/addresses", List.class);

        log.info("employeeAddressData, {}", employeeAddressData);
        Thread.sleep(1000L); // Intentional delay
        log.info("employeeAddressData completed");
        return CompletableFuture.completedFuture(employeeAddressData);
    }

    @Async("asyncExecutor")
    public CompletableFuture<List<String>> getEmployeePhone() throws InterruptedException {
        log.info("getEmployeePhone starts");

        List<String> employeePhoneData = restTemplate.getForObject("http://localhost:8080/phones", List.class);

        log.info("employeePhoneData, {}", employeePhoneData);
        Thread.sleep(1000L); // Intentional delay
        log.info("employeePhoneData completed");
        return CompletableFuture.completedFuture(employeePhoneData);
    }
}

3. controller

package com.example.demoasync;

import java.util.List;
import java.util.concurrent.CompletableFuture;
import java.util.concurrent.ExecutionException;

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RequestMethod;
import org.springframework.web.bind.annotation.RestController;

@RestController
public class AsyncController {
 
    private static Logger log = LoggerFactory.getLogger(AsyncController.class);
 
    @Autowired
    private AsyncService service;
 
    @RequestMapping(value = "/testAsynch", method = RequestMethod.GET)
    public void testAsynch() throws InterruptedException, ExecutionException
    {
        log.info("testAsynch Start");
 
        CompletableFuture<List<String>> employeeAddress = service.getEmployeeAddress();
        CompletableFuture<List<String>> employeeName = service.getEmployeeName();
        CompletableFuture<List<String>> employeePhone = service.getEmployeePhone();
 
        // 等待每个异步调用都完成
        CompletableFuture.allOf(employeeAddress, employeeName, employeePhone).join();
         
        log.info("EmployeeAddress--> " + employeeAddress.get());
        log.info("EmployeeName--> " + employeeName.get());
        log.info("EmployeePhone--> " + employeePhone.get());
    }
}