CountDownLatch使用-编程知识

CountDownLatch使用

常用于多线程场景，待多线程都结束后方可继续主线程逻辑处理

CodeConstant 常量类

import java.util.HashMap;
import java.util.Map;public class CodeConstant {public static final Map<String, Map<String, String>> CODE = new HashMap<>();static {//资产1CODE.put(AssetTypeEnum.ZICHAN_1.getCode(),new HashMap<String, String>() {{put("JS", "JS1");put("CHECK", "CHECK1");put("PUBLISH", "PUBLISH1");}});//资产2CODE.put(AssetTypeEnum.ZICHAN_2.getCode(),new HashMap<String, String>() {{put("JS", "JS1");put("CHECK", "CHECK2");put("PUBLISH", "PUBLISH2");}});}
}

CountDownLatchController

import com.example.demo.constant.CodeConstant;
import com.example.demo.service.TestCountDownLatchService;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.web.bind.annotation.PostMapping;
import org.springframework.web.bind.annotation.RequestMapping;
import org.springframework.web.bind.annotation.RestController;
import java.util.Arrays;
import java.util.List;
import java.util.Map;
import java.util.concurrent.CountDownLatch;@RestController
@RequestMapping("/countDownLatch")
public class CountDownLatchController {private static final Logger logger = LoggerFactory.getLogger(CountDownLatchController.class);@Autowiredprivate TestCountDownLatchService downLatchService;@PostMapping("/test")public void testCountDownLatch() {logger.info("测试多线程开始...");try {List<String> list = Arrays.asList("zichan1", "zichan2", "zichan3");CountDownLatch countDownLatch = new CountDownLatch(2);Map<String, Map<String, String>> map = CodeConstant.CODE;for (String type : list) {downLatchService.test(type, map, countDownLatch);}countDownLatch.await();} catch (InterruptedException e) {e.printStackTrace();}logger.info("测试多线程结束...");}}

TestCountDownLatchService 类

import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.scheduling.annotation.Async;
import org.springframework.stereotype.Service;
import java.util.Map;
import java.util.concurrent.CountDownLatch;@Service
public class TestCountDownLatchService {private static final Logger logger = LoggerFactory.getLogger(TestCountDownLatchService.class);@Asyncpublic void test(String type, Map<String, Map<String, String>> map, CountDownLatch countDownLatch) {Map<String, String> typeMap = map.get(type);if (typeMap == null) {countDownLatch.countDown();return;}try {logger.info("类型{}的信息{}", type, typeMap);for (int i = 0; i < 1000; i++) {for (int j = 0; j < 1000; j++) {logger.debug("i*j={}", i * j);}}} catch (Exception e) {logger.error("类型{}异常：", type, e);} finally {countDownLatch.countDown();}}
}

启动类上补充注解 @EnableAsync

import org.mybatis.spring.annotation.MapperScan;
import org.springframework.boot.SpringApplication;
import org.springframework.boot.autoconfigure.SpringBootApplication;
import org.springframework.scheduling.annotation.EnableAsync;@EnableAsync
@SpringBootApplication
@MapperScan(basePackages = { "com.example.demo" })
public class DemoApplication {public static void main(String[] args) {SpringApplication.run(DemoApplication.class, args);}
}