如何为spring-boot-2.1.6的HttpClient/TcpClient设置连接/读写超时？

一、连接超时配置的正确性修正 #

你当前的连接超时代码不生效，原因是Reactor Netty的配置类为不可变设计，调用tc.option(...)会返回一个新的TcpClient实例，必须将这个新实例赋值给tc才能让配置生效。修正后的代码如下：

final HttpClient httpClient = HttpClient.create()
        .tcpConfiguration(tc -> {
            Optional.ofNullable(getConnectTimeout())
                    .map(Duration::toMillis)
                    .map(Math::toIntExact)
                    .ifPresent(ct -> {
                        // 必须接收option返回的新实例，否则配置不会生效
                        tc = tc.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, ct);
                    });
            return tc;
        });

如果是固定时长的配置，可简化为：

final HttpClient httpClient = HttpClient.create()
        .tcpConfiguration(tc -> tc.option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 5000));

二、写入超时配置 #

写入超时需在客户端连接建立后添加WriteTimeoutHandler实现，有两种配置方式：

方式1：通过HttpClient的doOnConnected配置 #

final HttpClient httpClient = HttpClient.create()
        .doOnConnected(conn -> 
            conn.addHandlerLast(new WriteTimeoutHandler(10, TimeUnit.SECONDS))
        );

方式2：通过tcpConfiguration配置TcpClient #

final HttpClient httpClient = HttpClient.create()
        .tcpConfiguration(tc -> 
            tc.doOnConnected(conn -> 
                conn.addHandlerLast(new WriteTimeoutHandler(10, TimeUnit.SECONDS))
            )
        );

三、读取超时配置 #

读取超时的配置逻辑与写入超时一致，使用ReadTimeoutHandler即可：

方式1：通过HttpClient的doOnConnected配置 #

final HttpClient httpClient = HttpClient.create()
        .doOnConnected(conn -> 
            conn.addHandlerLast(new ReadTimeoutHandler(15, TimeUnit.SECONDS))
        );

方式2：通过tcpConfiguration配置TcpClient #

final HttpClient httpClient = HttpClient.create()
        .tcpConfiguration(tc -> 
            tc.doOnConnected(conn -> 
                conn.addHandlerLast(new ReadTimeoutHandler(15, TimeUnit.SECONDS))
            )
        );

四、单独使用TcpClient时的超时配置 #

如果直接使用TcpClient而非HttpClient，配置逻辑完全一致：

// 连接超时
TcpClient tcpClient = TcpClient.create()
        .option(ChannelOption.CONNECT_TIMEOUT_MILLIS, 5000);

// 写入+读取超时
tcpClient = tcpClient.doOnConnected(conn -> {
    conn.addHandlerLast(new WriteTimeoutHandler(10, TimeUnit.SECONDS));
    conn.addHandlerLast(new ReadTimeoutHandler(15, TimeUnit.SECONDS));
});

内容的提问来源于stack exchange，提问作者Jin Kwon