Java HttpClient中的三种超时设置区别

最近项目中在使用HttpClient有三个超时(connectionRequestTimeout,connectTimeout,socketTimeout)时间理解得不是很透彻，API文档不是很理解，专门写Demo理解了一下。

API的描述如下：

/**     * Returns the timeout in milliseconds used when requesting a connection     * from the connection manager. A timeout value of zero is interpreted     * as an infinite timeout.     * <p>     * A timeout value of zero is interpreted as an infinite timeout.     * A negative value is interpreted as undefined (system default).     * </p>     * <p>     * Default: {@code -1}     * </p>     */    public int getConnectionRequestTimeout() {        return connectionRequestTimeout;    }    /**     * Determines the timeout in milliseconds until a connection is established.     * A timeout value of zero is interpreted as an infinite timeout.     * <p>     * A timeout value of zero is interpreted as an infinite timeout.     * A negative value is interpreted as undefined (system default).     * </p>     * <p>     * Default: {@code -1}     * </p>     */    public int getConnectTimeout() {        return connectTimeout;    }    /**     * Defines the socket timeout ({@code SO_TIMEOUT}) in milliseconds,     * which is the timeout for waiting for data  or, put differently,     * a maximum period inactivity between two consecutive data packets).     * <p>     * A timeout value of zero is interpreted as an infinite timeout.     * A negative value is interpreted as undefined (system default).     * </p>     * <p>     * Default: {@code -1}     * </p>     */    public int getSocketTimeout() {        return socketTimeout;    }

正确解读一下

API中不能看出正式的含义是什么，经过demo之后，终于知道了各自含义

1. connectTimeOut：指建立连接的超时时间，比较容易理解

2. connectionRequestTimeOut：指从连接池获取到连接的超时时间，如果是非连接池的话，该参数暂时没有发现有什么用处

3. socketTimeOut：指客户端和服务进行数据交互的时间，是指两者之间如果两个数据包之间的时间大于该时间则认为超时，而不是整个交互的整体时间，比如如果设置1秒超时，如果每隔0.8秒传输一次数据，传输10次，总共8秒，这样是不超时的。而如果任意两个数据包之间的时间超过了1秒，则超时。

代码

首先是为这次demo写的服务代码，包含几个controller方法（Spring MVC）

package me.nabil.demo.springbootdemo;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import org.springframework.boot.SpringApplication;import org.springframework.boot.autoconfigure.EnableAutoConfiguration;import org.springframework.stereotype.Controller;import org.springframework.web.bind.annotation.RequestMapping;import org.springframework.web.bind.annotation.RequestMethod;import org.springframework.web.bind.annotation.ResponseBody;import javax.servlet.http.HttpServletRequest;import javax.servlet.http.HttpServletResponse;import java.io.IOException;/** * 超时测试 * * @author nabilzhang */@Controller@EnableAutoConfiguration@RequestMapping(value = {"/test"}, method = {RequestMethod.GET})public class TimeoutTestController {    private static final Logger logger = LoggerFactory.getLogger(TimeoutTestController.class);    /**     * main方法     *     * @param args 参数数组     */    public static void main(String args[]) {        SpringApplication.run(TimeoutTestController.class, args);    }    /**     * 1.测试socketOutTimeout，三秒后返回数据     *     * @return     * @throws InterruptedException     */    @RequestMapping(value = {"/socket_timeout"}, method = {RequestMethod.GET})    @ResponseBody    String socketTimeout() throws InterruptedException {        logger.info("socket_timeout");        Thread.sleep(3000);        return "socket_timeout";    }    /**     * 2.测试socketOutTimeout，每隔0.8秒返回数据     *     * @return     * @throws InterruptedException     */    @RequestMapping(value = {"/socket_timeout_2"}, method = {RequestMethod.GET})    void socketTimeout2(HttpServletResponse response) throws InterruptedException, IOException {        logger.info("socket_timeout_2");        for (int i = 0; i < 10; i++) {            logger.info("{}", i);            response.getWriter().println("" + i);            response.flushBuffer();            Thread.sleep(800);        }    }    /**     * 3.测试connectionRequestTimeout用的服务，三秒后返回数据     *     * @param request     * @return     * @throws InterruptedException     */    @RequestMapping(value = {"/connection_request_timeout"}, method = {RequestMethod.GET})    @ResponseBody    String connectionRequestTimeout(HttpServletRequest request) throws InterruptedException {        logger.info("{}", request.getRequestURI());        Thread.sleep(3000);        return "connectionRequestTimeout";    }}

如下是客户端的测试Case，下面几个Case分别测试了几个超时时间的各种情况，Case全部通过才可以

package me.nabil.demo.springbootdemo;import org.apache.http.client.ClientProtocolException;import org.apache.http.client.config.RequestConfig;import org.apache.http.client.methods.CloseableHttpResponse;import org.apache.http.client.methods.HttpGet;import org.apache.http.conn.ConnectTimeoutException;import org.apache.http.impl.client.CloseableHttpClient;import org.apache.http.impl.client.HttpClients;import org.apache.http.impl.conn.BasicHttpClientConnectionManager;import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;import org.apache.http.util.EntityUtils;import org.junit.Assert;import org.junit.Test;import java.io.IOException;import java.net.SocketTimeoutException;import java.util.Date;import java.util.concurrent.ExecutorService;import java.util.concurrent.Executors;/** * 测试HttpClient超时参数 * * @author nabilzhang */public class TimeoutTestControllerTest {    /**     * 1.connectionTimeout测试：IP无法链接，链接超时     *     * @throws Exception     */    @Test    public void connectionTimeout() throws Exception {        CloseableHttpClient httpclient = HttpClients.createDefault();        HttpGet httpGet = new HttpGet("http://74.125.203.100");        RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(1000)                .setSocketTimeout(1000).setConnectTimeout(1000).build();        httpGet.setConfig(requestConfig);        try {            httpclient.execute(httpGet);        } catch (ConnectTimeoutException exception) {            Assert.assertTrue(exception.getMessage().contains("connect timed out"));        }    }    /**     * 2.socketTimeout测试，服务端没有指定时间内任何响应，会超时     *     * @throws Exception     */    @Test    public void socketTimeout() throws Exception {        CloseableHttpClient httpclient = HttpClients.createDefault();        HttpGet httpGet = new HttpGet("http://127.0.0.1:8080/test/socket_timeout");        RequestConfig requestConfig = RequestConfig.custom()                .setSocketTimeout(1000).build();        httpGet.setConfig(requestConfig);        try {            httpclient.execute(httpGet);        } catch (SocketTimeoutException exception) {            Assert.assertEquals("Read timed out", exception.getMessage());        }    }    /**     * 3.socketTimeout测试：服务端隔800ms返回一点数据,不会超时     *     * @throws Exception     */    @Test    public void socketTimeoutNo() {        CloseableHttpClient httpclient = HttpClients.createDefault();        HttpGet httpGet = new HttpGet("http://127.0.0.1:8080/test/socket_timeout_2");        RequestConfig requestConfig = RequestConfig.custom().setConnectionRequestTimeout(1000)                .setSocketTimeout(1000).setConnectTimeout(1000).build();        httpGet.setConfig(requestConfig);        try {            httpclient.execute(httpGet);            CloseableHttpResponse response = httpclient.execute(httpGet);            System.out.println(String.format("socketTimeoutNo, %s", EntityUtils.toString(response.getEntity())));        } catch (Exception e) {            Assert.fail("服务端隔800ms返回一点数据,不会超时");        }    }    /**     * 4.connectionRequestTimeout测试:指从连接管理器(例如连接池)中拿到连接的超时时间     *     * @throws Exception     */    @Test    public void connectionRequestTimeoutWithPoolingConnectionManager() throws Exception {        PoolingHttpClientConnectionManager conMgr = new PoolingHttpClientConnectionManager();        conMgr.setMaxTotal(2);        final CloseableHttpClient httpclient = HttpClients.custom().setConnectionManager(conMgr).build();        final HttpGet httpGet = new HttpGet("http://127.0.0.1:8080/test/connection_request_timeout");        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(1000)                .setConnectionRequestTimeout(1000).setSocketTimeout(1000).build();        httpGet.setConfig(requestConfig);        // 如下多线程占满连接池        ExecutorService executorService = Executors.newFixedThreadPool(10);        for (int i = 0; i < 10; i++) {            executorService.submit(new Runnable() {                @Override                public void run() {                    try {                        CloseableHttpResponse response = httpclient.execute(httpGet);                        System.out.println(String.format("connectionRequestTimeoutTest: %s",                                EntityUtils.toString(response.getEntity())));                    } catch (SocketTimeoutException exception) {                        System.out.println(exception.getMessage());                    } catch (ClientProtocolException e) {                        e.printStackTrace();                    } catch (IOException e) {                        e.printStackTrace();                    }                }            });        }        // 在连接池占满的情况下，拿不到就会抛异常        try {            CloseableHttpResponse response = httpclient.execute(httpGet);            System.out.println(String.format("connectionRequestTimeoutTest: %s",                    EntityUtils.toString(response.getEntity())));            Assert.fail();        } catch (Exception exception) {            // 异常是从连接池拿到连接超时            Assert.assertEquals("Timeout waiting for connection from pool", exception.getMessage());            System.out.println(exception.getMessage());        }    }    /**     * 5.connectionRequestTimeout测试，指从连接管理器中拿到连接的超时时间，由于使用基本的连接管理器，链接被占用时，直接无法分配链接     * connectionRequestTimeout并未生效，目前看来该参数只在连接池奏效.     * 该链接管理器(BasicHttpClientConnectionManager)是单线程情况下可以使用，多线程情况下不要使用。     *     * @throws Exception     */    @Test    public void connectionRequestTimeoutWithBasicConnectionManager() throws Exception {        BasicHttpClientConnectionManager connManager = new BasicHttpClientConnectionManager();        final CloseableHttpClient httpclient = HttpClients.custom()                .setConnectionManager(connManager).setMaxConnPerRoute(1).build();        final HttpGet httpGet = new HttpGet("http://127.0.0.1:8080/test/connection_request_timeout");        RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(100000)                .setConnectionRequestTimeout(1000000).setSocketTimeout(1000000).build();        httpGet.setConfig(requestConfig);        // 如下多线程占满连接        ExecutorService executorService = Executors.newFixedThreadPool(10);        for (int i = 0; i < 10; i++) {            executorService.submit(new Runnable() {                @Override                public void run() {                    CloseableHttpResponse response = null;                    try {                        response = httpclient.execute(httpGet);                        System.out.println(String.format("connectionRequestTimeoutTest: %s",                                EntityUtils.toString(response.getEntity())));                    } catch (Exception exception) {                        exception.printStackTrace();                    } finally {                        if (response != null) {                            try {                                response.close();                                httpclient.close();                            } catch (IOException e) {                                e.printStackTrace();                            }                        }                    }                }            });        }        System.out.println(new Date());        // 在连接池占满的情况下，拿不到就会抛异常        try {            CloseableHttpResponse response = httpclient.execute(httpGet);            System.out.println(String.format("connectionRequestTimeoutTest: %s",                    EntityUtils.toString(response.getEntity())));            Assert.fail();        } catch (Exception exception) {            System.out.println(new Date());            exception.printStackTrace();            // 异常是从连接池拿到连接超时            Assert.assertEquals("Connection is still allocated", exception.getMessage());            System.out.println(exception.getMessage());        }    }}

注：上面Case是使用httpclient版本4.5.2测试所得。

<dependency>            <groupId>org.apache.httpcomponents</groupId>            <artifactId>httpclient</artifactId>            <version>4.5.2</version>            <type>jar</type>        </dependency>

更深理解可以参照:http://www.baeldung.com/httpclient-connection-management