java9系列(六)HTTP/2 Client (Incubator)

序

本文主要研究下JEP 110: HTTP/2 Client (Incubator)

基本實例

sync get

/**
     * --add-modules jdk.incubator.httpclient
     * @throws IOException
     * @throws InterruptedException
     * @throws URISyntaxException
     */
    @Test
    public void testGet() throws IOException, InterruptedException, URISyntaxException {
        HttpClient httpClient = HttpClient.newHttpClient();
        HttpRequest httpRequest = HttpRequest.newBuilder()
                .uri(new URI("https://www.baidu.com"))
                .header("User-Agent", "jdk 9 http client")
                .GET()
                .build();
        HttpResponse<String> httpResponse = httpClient.send(httpRequest, HttpResponse.BodyHandler.asString());
        System.out.println(httpResponse.statusCode());
        System.out.println(httpResponse.body());
    }

因爲jdk9模塊化了，junit這裏沒有模塊化，須要在javac編譯時添加--add-modules jdk.incubator.httpclient，不然報錯以下：

Error:(3, 21) java: 程序包 jdk.incubator.http 不可見
  (程序包 jdk.incubator.http 已在模塊 jdk.incubator.httpclient 中聲明, 但該模塊不在模塊圖中)

在java運行時也要添加--add-modules jdk.incubator.httpclient，不然報NoClassDefFoundError

java.lang.NoClassDefFoundError: jdk/incubator/http/HttpResponse

    at java.base/java.lang.Class.getDeclaredMethods0(Native Method)
    at java.base/java.lang.Class.privateGetDeclaredMethods(Class.java:3139)
    at java.base/java.lang.Class.getDeclaredMethods(Class.java:2266)
    at org.junit.internal.MethodSorter.getDeclaredMethods(MethodSorter.java:54)
    at org.junit.runners.model.TestClass.scanAnnotatedMembers(TestClass.java:65)
    at org.junit.runners.model.TestClass.<init>(TestClass.java:57)
    at org.junit.runners.ParentRunner.createTestClass(ParentRunner.java:88)
    at org.junit.runners.ParentRunner.<init>(ParentRunner.java:83)
    at org.junit.runners.BlockJUnit4ClassRunner.<init>(BlockJUnit4ClassRunner.java:65)
    at org.junit.internal.builders.JUnit4Builder.runnerForClass(JUnit4Builder.java:10)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.builders.AllDefaultPossibilitiesBuilder.runnerForClass(AllDefaultPossibilitiesBuilder.java:26)
    at org.junit.runners.model.RunnerBuilder.safeRunnerForClass(RunnerBuilder.java:59)
    at org.junit.internal.requests.ClassRequest.getRunner(ClassRequest.java:33)
    at org.junit.internal.requests.FilterRequest.getRunner(FilterRequest.java:36)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:49)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:47)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)
Caused by: java.lang.ClassNotFoundException: jdk.incubator.http.HttpResponse
    at java.base/jdk.internal.loader.BuiltinClassLoader.loadClass(BuiltinClassLoader.java:582)
    at java.base/jdk.internal.loader.ClassLoaders$AppClassLoader.loadClass(ClassLoaders.java:185)
    at java.base/java.lang.ClassLoader.loadClass(ClassLoader.java:496)
    ... 19 more

async get

@Test
    public void testAsyncGet() throws URISyntaxException, InterruptedException, ExecutionException {
        HttpClient client = HttpClient.newHttpClient();

        HttpRequest request = HttpRequest.newBuilder()
                .uri(new URI("https://www.baidu.com"))
                .GET()
                .build();

        CompletableFuture<HttpResponse<String>> response = client.sendAsync(request, HttpResponse.BodyHandler.asString());

        response.whenComplete((resp,t) -> {
            if(t != null){
                t.printStackTrace();
            }else{
                System.out.println(resp.body());
                System.out.println(resp.statusCode());
            }
        }).join();
    }

post form

@Test
    public void testPostForm() throws URISyntaxException {
        HttpClient client = HttpClient.newHttpClient();

        HttpRequest request = HttpRequest.newBuilder()
                .uri(new URI("http://www.w3school.com.cn/demo/demo_form.asp"))
                .header("Content-Type","application/x-www-form-urlencoded")
                .POST(HttpRequest.BodyProcessor.fromString("name1=value1&name2=value2"))
                .build();
        client.sendAsync(request, HttpResponse.BodyHandler.asString())
                .whenComplete((resp,t) -> {
                    if(t != null){
                        t.printStackTrace();
                    }else{
                        System.out.println(resp.body());
                        System.out.println(resp.statusCode());
                    }
        }).join();
    }

HTTP/2

curl http2

• 安裝

brew install curl --with-nghttp2
==> Installing dependencies for curl: jemalloc, nghttp2
==> Installing curl dependency: jemalloc
==> Downloading https://homebrew.bintray.com/bottles/jemalloc-5.0.1.sierra.bottl
######################################################################## 100.0%
==> Pouring jemalloc-5.0.1.sierra.bottle.tar.gz
?  /usr/local/Cellar/jemalloc/5.0.1: 16 files, 1.6MB
==> Installing curl dependency: nghttp2
==> Downloading https://homebrew.bintray.com/bottles/nghttp2-1.31.0.sierra.bottl
######################################################################## 100.0%
==> Pouring nghttp2-1.31.0.sierra.bottle.tar.gz
?  /usr/local/Cellar/nghttp2/1.31.0: 33 files, 6.3MB
==> Installing curl --with-nghttp2
==> Downloading https://curl.haxx.se/download/curl-7.58.0.tar.bz2
######################################################################## 100.0%
==> ./configure --disable-silent-rules --prefix=/usr/local/Cellar/curl/7.58.0 --
==> make install
==> Caveats
This formula is keg-only, which means it was not symlinked into /usr/local,
because macOS already provides this software and installing another version in
parallel can cause all kinds of trouble.

If you need to have this software first in your PATH run:
  echo 'export PATH="/usr/local/opt/curl/bin:$PATH"' >> ~/.zshrc

For compilers to find this software you may need to set:
    LDFLAGS:  -L/usr/local/opt/curl/lib
    CPPFLAGS: -I/usr/local/opt/curl/include
For pkg-config to find this software you may need to set:
    PKG_CONFIG_PATH: /usr/local/opt/curl/lib/pkgconfig

==> Summary
?  /usr/local/Cellar/curl/7.58.0: 415 files, 3MB, built in 2 minutes 37 seconds

• 檢查

curl -V
curl 7.58.0 (x86_64-apple-darwin16.7.0) libcurl/7.58.0 OpenSSL/1.0.2n zlib/1.2.8 nghttp2/1.31.0
Release-Date: 2018-01-24
Protocols: dict file ftp ftps gopher http https imap imaps ldap ldaps pop3 pop3s rtsp smb smbs smtp smtps telnet tftp
Features: AsynchDNS IPv6 Largefile NTLM NTLM_WB SSL libz TLS-SRP HTTP2 UnixSockets HTTPS-proxy

• 訪問

curl -I --http2 https://http2.akamai.com/demo
HTTP/2 200
server: Apache
etag: "07ce30bc53aa7834dff55f92a6d05a56:1466062139"
last-modified: Thu, 16 Jun 2016 07:28:59 GMT
accept-ranges: bytes
content-length: 2421
content-type: text/html
rtt: 186
ghost_ip: 23.193.143.145
ghost_service_ip: 107.14.44.207
client_real_ip: 210.21.215.42
client_ip: 210.21.215.42
myproto: h2
protocol_negotiation: h2
expires: Mon, 05 Mar 2018 01:15:17 GMT
cache-control: max-age=0, no-cache, no-store
pragma: no-cache
date: Mon, 05 Mar 2018 01:15:17 GMT
accept-ch: DPR, Width, Viewport-Width, Downlink, Save-Data
access-control-max-age: 86400
access-control-allow-credentials: false
access-control-allow-headers: *
access-control-allow-methods: GET,HEAD,POST
access-control-allow-origin: *
strict-transport-security: max-age=31536000 ; includeSubDomains

HTTP/2實例

@Test
    public void testHttp2() throws URISyntaxException, IOException, InterruptedException {
        HttpClient.newBuilder()
                .followRedirects(HttpClient.Redirect.SECURE)
                .version(HttpClient.Version.HTTP_2)
                .build()
                .sendAsync(HttpRequest.newBuilder()
                                .uri(new URI("https://http2.akamai.com/demo"))
                                .GET()
                                .build(),
                        HttpResponse.BodyHandler.asString())
                .whenComplete((resp,t) -> {
                    if(t != null){
                        t.printStackTrace();
                    }else{
                        System.out.println(resp.body());
                        System.out.println(resp.statusCode());
                    }
                }).join();
    }

小結

jdk9的httpclient如今還在incubator中，最大的特性即是支持HTTP/2，固然也優化了httpclient的api，同時也支持了異步模式。鑑於它還處在incubator，若是不是着急使用HTTP/2，建議仍是使用spring5的webclient，它是遵循reactive-streams規範的，使用起來更加方便。reactor-netty貌似要在0.9.0.RELEASE版本才支持HTTP/2。

doc

• JDK 9 features
• Getting Started With Java 9's New HTTP Client
• Java 9: The New HttpClient
• Java 9 揭祕（14. HTTP/2 Client API）
• 讓 curl 支持 HTTP/2 協議
• 如何啓用curl命令HTTP2支持
• Add Http2 support #104
• Java 9: High level HTTP and WebSocket API