Java怎么获取线程状态及堆栈信息

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基本概念

出现内存泄漏或者运行缓慢场景，有时候无法直接从业务日志看出问题时候，需要分析jvm内存和线程堆栈

线程堆栈信息主要记录jvm线程在某时刻线程执行情况，分析线程状态可以跟踪到程序出问题的地方内存堆栈信息主要记录jvm堆中在某时刻对象使用情况，主要用于跟踪是哪个对象占用了太多的空间，从而跟踪导致内存泄漏的地方

跟踪线程信息

查看当前线程数量

actuator

1.x

http://host:port/metrics/threads //当前进程的线程数http://host:port/metrics/threads.daemon  //当前进程后台驻留线程数http://host:port/metrics/threads.peak  //当前进程线程数峰值

2.x

http://host:port/actuator/metrics/jvm.threads.daemon  //当前进程后台驻留线程数http://host:port/actuator/metrics/jvm.threads.live  //当前进程的线程数http://host:port/actuator/metrics/jvm.threads.peak  //当前进程线程数峰值

hystrix 线程状态

如果接入了turbine可以直接通过turbine查看整个集群状态

当集群较大的时候，单纯想看hystrix线程池状态，可以单独从hystrix监控统计类里面获取

http://host:port/sys/hystrix/threads

源码如下：

import com.alibaba.fastjson.JSON;import com.netflix.hystrix.HystrixThreadPoolMetrics;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.jmx.export.annotation.ManagedResource;import org.springframework.scheduling.annotation.EnableScheduling;import org.springframework.scheduling.annotation.Scheduled;import org.springframework.web.bind.annotation.GetMapping;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RestController;import java.util.List;import java.util.stream.Collectors;/** * @author yugj * @date 19/5/5 22:17. */@RestController@RequestMapping(path = "/sys/hystrix")@ManagedResource(description = "hystrix Endpoint")@EnableSchedulingpublic class HystrixThreadPoolEndpoint {    private boolean showStats = false;    private static final Logger log = LoggerFactory.getLogger(HystrixThreadPoolEndpoint.class);    @GetMapping(value = "/threads")    public List threadStats() {        return HystrixThreadPoolMetrics.getInstances().stream().map((m) -> {            final HystrixThreadStats stats = new HystrixThreadStats();            stats.poolName = m.getThreadPoolKey().name();            stats.cumulativeExecuted = m.getCumulativeCountThreadsExecuted();            stats.currentActiveCount = m.getCurrentActiveCount().intValue();            stats.currentCompletedCount = m.getCurrentCompletedTaskCount().intValue();            stats.currentCorePoolSize = m.getCurrentCorePoolSize().intValue();            stats.currentLargestPoolSize = m.getCurrentLargestPoolSize().intValue();            stats.currentMaxPoolSize = m.getCurrentMaximumPoolSize().intValue();            stats.currentPoolSize = m.getCurrentPoolSize().intValue();            stats.currentQueueSize = m.getCurrentQueueSize().intValue();            stats.currentTaskCount = m.getCurrentTaskCount().intValue();            return stats;        }).collect(Collectors.toList());    }    @GetMapping(value = "/setShowStats")    public String setShowStats(Boolean showStats) {        if (showStats != null) {            this.showStats = showStats;        }        return "this.show stats:" + this.showStats;    }    @Scheduled(fixedRate = 5000)    public void showStats() {        if (showStats) {            List statsList = threadStats();            log.info("thread stats :{}", JSON.toJSONString(statsList));        }    }    class HystrixThreadStats {        private String poolName;        private Long cumulativeExecuted;        private Integer currentActiveCount;        private Integer currentCompletedCount;        private Integer currentCorePoolSize;        private Integer currentLargestPoolSize;        private Integer currentMaxPoolSize;        private Integer currentPoolSize;        private Integer currentQueueSize;        private Integer currentTaskCount;        public String getPoolName() {            return poolName;        }        public void setPoolName(String poolName) {            this.poolName = poolName;        }        public Long getCumulativeExecuted() {            return cumulativeExecuted;        }        public void setCumulativeExecuted(Long cumulativeExecuted) {            this.cumulativeExecuted = cumulativeExecuted;        }        public Integer getCurrentActiveCount() {            return currentActiveCount;        }        public void setCurrentActiveCount(Integer currentActiveCount) {            this.currentActiveCount = currentActiveCount;        }        public Integer getCurrentCompletedCount() {            return currentCompletedCount;        }        public void setCurrentCompletedCount(Integer currentCompletedCount) {            this.currentCompletedCount = currentCompletedCount;        }        public Integer getCurrentCorePoolSize() {            return currentCorePoolSize;        }        public void setCurrentCorePoolSize(Integer currentCorePoolSize) {            this.currentCorePoolSize = currentCorePoolSize;        }        public Integer getCurrentLargestPoolSize() {            return currentLargestPoolSize;        }        public void setCurrentLargestPoolSize(Integer currentLargestPoolSize) {            this.currentLargestPoolSize = currentLargestPoolSize;        }        public Integer getCurrentMaxPoolSize() {            return currentMaxPoolSize;        }        public void setCurrentMaxPoolSize(Integer currentMaxPoolSize) {            this.currentMaxPoolSize = currentMaxPoolSize;        }        public Integer getCurrentPoolSize() {            return currentPoolSize;        }        public void setCurrentPoolSize(Integer currentPoolSize) {            this.currentPoolSize = currentPoolSize;        }        public Integer getCurrentQueueSize() {            return currentQueueSize;        }        public void setCurrentQueueSize(Integer currentQueueSize) {            this.currentQueueSize = currentQueueSize;        }        public Integer getCurrentTaskCount() {            return currentTaskCount;        }        public void setCurrentTaskCount(Integer currentTaskCount) {            this.currentTaskCount = currentTaskCount;        }    }}

linux

ps huH p {pid}|wc -l

jstack生成线程堆栈

当服务cup飙升或者出问题需要从主机层面定位时候，使用top -c 命令查看对应哪个进程占用了过高资源

找到资源占用高的进程

明确需要定位的进程通过如下命令找到对应的进程id

ps aux|grep {application alias}

可以通过如下命令定位具体高load线程：

查询进程具体哪个线程占用高loadtop -Hp {进程pid}thread id为十六进制格式转十六进制值printf %x {线程pid}指定特定行数堆栈信息jstack {进程id}|grep -A 200 {线程id}

接下来通过jstack导出对应的线程堆栈

jstack 对应参数如下

• -m to print both java and native frames (mixed mode)

• -l long listing. Prints additional information about locks

服务器线程相对较多，文件大小较大，一般不会考虑在服务器看，另外这样查也会导致忽略了一些统计信息

通过如下命令导出文件，下载到本地查

jstack -l {pid} >> {dump-file-path}

docker环境涉及一些权限，需要进入docker执行，docker里面进程id根据实际情况，一般会联系运维操作

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