转载

Spring Boot 应用如何提高服务吞吐量?

意外和明天不知道哪个先来。没有危机是最大的危机，满足现状是最大的陷阱。

背景

生产环境偶尔会有一些慢请求导致系统性能下降，吞吐量下降，下面介绍几种优化建议。

方案

1、undertow替换tomcat

电子商务类型网站大多都是短请求，一般响应时间都在100ms，这时可以将web容器从tomcat替换为undertow，下面介绍下步骤：1、增加pom配置

<dependency>
    <groupid>
        org.springframework.boot
    </groupid>
    <artifactid>
        spring-boot-starter-web
    </artifactid>
    <exclusions>
        <exclusion>
            <groupid>
                org.springframework.boot
            </groupid>
            <artifactid>
                spring-boot-starter-tomcat
            </artifactid>
        </exclusion>
    </exclusions>
</dependency>
<dependency>
    <groupid>
        org.springframework.boot
    </groupid>
    <artifactid>
        spring-boot-starter-undertow
    </artifactid>
</dependency>

2、增加相关配置

server:
  undertow:
    direct-buffers: true
    io-threads: 4
    worker-threads: 160

重新启动可以在控制台看到容器已经切换为undertow了

2、缓存

将部分热点数据或者静态数据放到本地缓存或者redis中，如果有需要可以定时更新缓存数据

3、异步

在代码过程中我们很多代码都不需要等返回结果，也就是部分代码是可以并行执行，这个时候可以使用异步，最简单的方案是使用springboot提供的@Async注解，当然也可以通过线程池来实现，下面简单介绍下异步步骤。1、pom依赖一般springboot引入web相关依赖就行

<dependency>
    <groupid>
        org.springframework.boot
    </groupid>
    <artifactid>
        spring-boot-starter-web
    </artifactid>
</dependency>

2、在启动类中增加@EnableAsync注解

import org.springframework.boot.SpringApplication

@EnableAsync
@SpringBootApplication
public class AppApplication {
    public static void main(String[] args) {
        SpringApplication.run(AppApplication.class, args);
    }
}

3、需要时在指定方法中增加@Async注解，如果是需要等待返回值，则demo如下

@Async
public Future<String> doReturn(int i) {
    try {
        // 这个方法需要调用500毫秒
        Thread.sleep(500);
    } catch (InterruptedException e) {
        e.printStackTrace();
    }
    // 消息汇总
    return new AsyncResult<String>("异步调用");
}

4、如果有线程变量或者logback中的mdc，可以增加传递

import org.slf4j.MDC;
import org.springframework.context.annotation.Configuration;
import org.springframework.core.task.TaskDecorator;
import org.springframework.scheduling.annotation.AsyncConfigurerSupport;
import org.springframework.scheduling.annotation.EnableAsync;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.Map;
import java.util.concurrent.Executor;

/**
 * @Description:
 */
@EnableAsync
@Configuration
public class AsyncConfig extends AsyncConfigurerSupport {
    @Override
    public Executor getAsyncExecutor() {
        ThreadPoolTaskExecutor executor = new ThreadPoolTaskExecutor();
        executor.setTaskDecorator(new MdcTaskDecorator());
        executor.initialize();
        return executor;
    }
}

class MdcTaskDecorator implements TaskDecorator {

    @Override
    public Runnable decorate(Runnable runnable) {
        Map<string, string> contextMap = MDC.getCopyOfContextMap();
        return () - & gt; {
            try {
                MDC.setContextMap(contextMap);
                runnable.run();
            } finally {
                MDC.clear();
            }
        };
    }
}

5、有时候异步需要增加阻塞

import lombok.extern.slf4j.Slf4j;
import org.springframework.context.annotation.Bean;
import org.springframework.context.annotation.Configuration;
import org.springframework.scheduling.concurrent.ThreadPoolTaskExecutor;

import java.util.concurrent.Executor;
import java.util.concurrent.ThreadPoolExecutor;

@Configuration
@Slf4j
public class TaskExecutorConfig {

    @Bean("localDbThreadPoolTaskExecutor")
    public Executor threadPoolTaskExecutor() {
        ThreadPoolTaskExecutor taskExecutor = new ThreadPoolTaskExecutor();
        taskExecutor.setCorePoolSize(5);
        taskExecutor.setMaxPoolSize(200);
        taskExecutor.setQueueCapacity(200);
        taskExecutor.setKeepAliveSeconds(100);
        taskExecutor.setThreadNamePrefix("LocalDbTaskThreadPool");
        taskExecutor.setRejectedExecutionHandler((Runnable r, ThreadPoolExecutor executor) - & gt; {
            if (!executor.isShutdown()) {
                try {
                    Thread.sleep(300);
                    executor.getQueue().put(r);
                } catch (InterruptedException e) {
                    log.error(e.toString(), e);
                    Thread.currentThread().interrupt();
                }
            }
        }
        );
        taskExecutor.initialize();
        return taskExecutor;
    }
}