什么是HTTPS

严格地讲，HTTPS并不是一个单独的协议，而是对工作在一加密连接（TLS或SSL）上的常规HTTP协议的称呼。

TLS/SSL

关于TLS/SSL的介绍网上已经有很多，大家可以参考《SSL/TLS协议运行机制的概述》和 《图解SSL/TLS协议》中的介绍

Java与HTTPS

JDK中对 HTTPS 版本的支持情况

• JDK 6
  SSL v3
  TLS v1(默认)
  TLS v1.1(JDK6 update 111 及以上)

• JDK 7
  SSLv3
  TLS v1(默认)
  TLS v1.1
  TLS v1.2

• JDK 8
  SSL v3
  TLS v1
  TLS v1.1
  TLS v1.2(默认)

Java在使用HTTPS时遇到的问题

首先看一个错误:

java.net.SocketException: Connection reset

    at java.net.SocketInputStream.read(SocketInputStream.java:196)
    at java.net.SocketInputStream.read(SocketInputStream.java:122)
    at sun.security.ssl.InputRecord.readFully(InputRecord.java:442)
    at sun.security.ssl.InputRecord.read(InputRecord.java:480)
    at sun.security.ssl.SSLSocketImpl.readRecord(SSLSocketImpl.java:934)
    at sun.security.ssl.SSLSocketImpl.performInitialHandshake(SSLSocketImpl.java:1332)
    at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1359)
    at sun.security.ssl.SSLSocketImpl.startHandshake(SSLSocketImpl.java:1343)
    at sun.net.www.protocol.https.HttpsClient.afterConnect(HttpsClient.java:559)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(AbstractDelegateHttpsURLConnection.java:185)
    at sun.net.www.protocol.http.HttpURLConnection.getInputStream(HttpURLConnection.java:1301)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.getInputStream(HttpsURLConnectionImpl.java:254)
    at httpsTest.HttpsSendTest.basicHttpsGet(HttpsSendTest.java:38)
    at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
    at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
    at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
    at java.lang.reflect.Method.invoke(Method.java:606)
    at org.junit.runners.model.FrameworkMethod$1.runReflectiveCall(FrameworkMethod.java:44)
    at org.junit.internal.runners.model.ReflectiveCallable.run(ReflectiveCallable.java:15)
    at org.junit.runners.model.FrameworkMethod.invokeExplosively(FrameworkMethod.java:41)
    at org.junit.internal.runners.statements.InvokeMethod.evaluate(InvokeMethod.java:20)
    at org.junit.runners.BlockJUnit4ClassRunner.runNotIgnored(BlockJUnit4ClassRunner.java:79)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:71)
    at org.junit.runners.BlockJUnit4ClassRunner.runChild(BlockJUnit4ClassRunner.java:49)
    at org.junit.runners.ParentRunner$3.run(ParentRunner.java:193)
    at org.junit.runners.ParentRunner$1.schedule(ParentRunner.java:52)
    at org.junit.runners.ParentRunner.runChildren(ParentRunner.java:191)
    at org.junit.runners.ParentRunner.access$000(ParentRunner.java:42)
    at org.junit.runners.ParentRunner$2.evaluate(ParentRunner.java:184)
    at org.junit.runners.ParentRunner.run(ParentRunner.java:236)
    at org.junit.runner.JUnitCore.run(JUnitCore.java:157)
    at com.intellij.junit4.JUnit4IdeaTestRunner.startRunnerWithArgs(JUnit4IdeaTestRunner.java:68)
    at com.intellij.rt.execution.junit.IdeaTestRunner$Repeater.startRunnerWithArgs(IdeaTestRunner.java:51)
    at com.intellij.rt.execution.junit.JUnitStarter.prepareStreamsAndStart(JUnitStarter.java:242)
    at com.intellij.rt.execution.junit.JUnitStarter.main(JUnitStarter.java:70)

背景

最近在使用的第三方接口升级了TLS协议，只支持TLSv1.2，而我们的机器使用的JDK版本为JDK1.7，默认使用的是TLSv1，所以当服务端只支持TLSv1.2时会报异常

解决

解决方案很简单，只需要在启动参数加上-Dhttps.protocols=TLSv1.2即可

下面我们验证下此解决方案是否有效

• 使用 HttpURLConnection发送HTTPS请求访问百度（未修改启动参数）

/**
 * Created by wujiang on 2017/6/30.
 */
public class HttpsSendTest {
    @Test
    public void basicHttpsGet() throws Exception {

        String url = "https://www.baidu.com";

        URL obj = new URL(url);

        SSLContext sslContext = SSLContext.getInstance("TLSv1.2");
        sslContext.init(null, null, null);

        HttpsURLConnection con = (HttpsURLConnection) obj.openConnection();
        con.setRequestProperty("User-Agent", "Mozilla/5.0 (Windows NT 6.1; WOW64) ...");
        con.setRequestProperty("Accept-Language", "en-US,en;q=0.5");
        con.setRequestMethod("GET");

        InputStream inputStream = con.getInputStream();
        Scanner scanner = new Scanner(inputStream, "UTF-8");
        String text = scanner.useDelimiter("\\A").next();
        System.out.println(text);
        scanner.close();
    }
}

• 通过wireShark抓包可以看到使用的协议为TLSv1（JDK1.7）

• 修改启动参数（jdk1.7）

再次请求 可以看到协议变为TLSv1.2

• 使用JDK1.8我们再看看