okhttp3：無法創建新的本機線程

Question

遇到一個奇怪的問題，嘗試了幾次后無法重現。 如何重現它以及它為什么發生？

這是一個非並發任務，循環調用 HTTP 連接。

    public static Response syncGet(URL url) throws IOException {
        log.debug("http url:{}", url);
        OkHttpClient client = new OkHttpClient().newBuilder().connectTimeout(15L, TimeUnit.SECONDS)
                .readTimeout(30L, TimeUnit.SECONDS).build();

        Request request = new Request.Builder().url(url).get().addHeader("cache-control", "no-cache").build();
        Call call = client.newCall(request);
        return call.execute();
    }

堆：

2019-12-05 11:20:56.068 ERROR 18484 --- [   scheduling-1] o.s.s.s.TaskUtils$LoggingErrorHandler    : Unexpected error occurred in scheduled task

    java.lang.OutOfMemoryError: unable to create new native thread
        at java.lang.Thread.start0(Native Method) [na:1.8.0_181]
        at java.lang.Thread.start(Thread.java:717) [na:1.8.0_181]
        at java.util.concurrent.ThreadPoolExecutor.addWorker(ThreadPoolExecutor.java:957) [na:1.8.0_181]
        at java.util.concurrent.ThreadPoolExecutor.execute(ThreadPoolExecutor.java:1378) [na:1.8.0_181]
        at okhttp3.ConnectionPool.put(ConnectionPool.java:153) ~[okhttp-3.12.1.jar:na]
        at okhttp3.OkHttpClient$1.put(OkHttpClient.java:167) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.connection.StreamAllocation.findConnection(StreamAllocation.java:266) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.connection.StreamAllocation.findHealthyConnection(StreamAllocation.java:135) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.connection.StreamAllocation.newStream(StreamAllocation.java:114) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.connection.ConnectInterceptor.intercept(ConnectInterceptor.java:42) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.cache.CacheInterceptor.intercept(CacheInterceptor.java:93) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.BridgeInterceptor.intercept(BridgeInterceptor.java:93) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RetryAndFollowUpInterceptor.intercept(RetryAndFollowUpInterceptor.java:126) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:147) ~[okhttp-3.12.1.jar:na]
        at okhttp3.internal.http.RealInterceptorChain.proceed(RealInterceptorChain.java:121) ~[okhttp-3.12.1.jar:na]
        at okhttp3.RealCall.getResponseWithInterceptorChain(RealCall.java:254) ~[okhttp-3.12.1.jar:na]
        at okhttp3.RealCall.execute(RealCall.java:92) ~[okhttp-3.12.1.jar:na]
        at chances.cms.util.HttpUtil.syncGet(HttpUtil.java:67) ~[classes/:na]
        at chances.cms.task.CheckTask.checkContent(CheckTask.java:76) ~[classes/:na]
        at chances.cms.task.CheckTask.check(CheckTask.java:60) ~[classes/:na]
        at chances.cms.task.CheckTask.check(CheckTask.java:51) ~[classes/:na]
        at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method) ~[na:1.8.0_181]
        at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:62) ~[na:1.8.0_181]
        at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43) ~[na:1.8.0_181]
        at java.lang.reflect.Method.invoke(Method.java:498) ~[na:1.8.0_181]
        at org.springframework.scheduling.support.ScheduledMethodRunnable.run(ScheduledMethodRunnable.java:84) ~[spring-context-5.2.1.RELEASE.jar:5.2.1.RELEASE]
        at org.springframework.scheduling.support.DelegatingErrorHandlingRunnable.run(DelegatingErrorHandlingRunnable.java:54) ~[spring-context-5.2.1.RELEASE.jar:5.2.1.RELEASE]
        at org.springframework.scheduling.concurrent.ReschedulingRunnable.run(ReschedulingRunnable.java:93) [spring-context-5.2.1.RELEASE.jar:5.2.1.RELEASE]
        at java.util.concurrent.Executors$RunnableAdapter.call(Executors.java:511) [na:1.8.0_181]
        at java.util.concurrent.FutureTask.run(FutureTask.java:266) [na:1.8.0_181]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.access$201(ScheduledThreadPoolExecutor.java:180) [na:1.8.0_181]
        at java.util.concurrent.ScheduledThreadPoolExecutor$ScheduledFutureTask.run(ScheduledThreadPoolExecutor.java:293) [na:1.8.0_181]
        at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1149) [na:1.8.0_181]
        at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:624) [na:1.8.0_181]
        at java.lang.Thread.run(Thread.java:748) [na:1.8.0_181]

Answer 1

OkHttpClients 應該被共享

當您創建單個 OkHttpClient 實例並將其重用於所有 HTTP 調用時，OkHttp 的性能最佳。 這是因為每個客戶端都擁有自己的連接池和線程池。 重用連接和線程可減少延遲並節省內存。

更多細節： https : //square.github.io/okhttp/3.x/okhttp/okhttp3/OkHttpClient.html

因此在syncGet方法之外創建client應該可以解決您的問題。