Spring RestTemplet https请求

基础知识：

　　微服务都是以HTTP接口的形式暴露自身服务的，因此在调用远程服务时就必须使用HTTP客户端。我们可以使用JDK原生的URLConnection、Apache的Http Client、Netty的异步HTTP Client,最方便、最优雅的Feign, Spring的RestTemplate等。

RestTemplate简述：
         RestTemplate是Spring提供的用于访问Rest服务(Rest风格、Rest架构)的客户端。
         RestTemplate提供了多种便捷访问远程Http服务的方法,能够大大提高客户端的编写效率。

调用RestTemplate的默认构造函数，RestTemplate对象在底层通过使用java.net包下的实现创建HTTP 请求;我们也可以通过使用ClientHttpRequestFactory指定不同的请求方式:

ClientHttpRequestFactory接口主要提供了两种实现方式:

        1.常用的一种是SimpleClientHttpRequestFactory，使用J2SE提供的方式（既java.net包提供的方式）创建底层
            的Http请求连接。

         2.常用的另一种方式是使用HttpComponentsClientHttpRequestFactory方式，底层使用HttpClient访问远程的
             Http服务，使用HttpClient可以配置连接池和证书等信息。

HTTP请求没有什么特殊要做的这里主要说HTTPS: HTTPS请求 = 超文本传输协议HTTP + 。

解决办法：创建自定义 ClientHttpRequestFactory

package com.zy.cm.common.core.config;
 
import org.springframework.http.client.SimpleClientHttpRequestFactory;
 
import javax.net.ssl.*;
import java.io.IOException;
import java.net.HttpURLConnection;
import java.net.InetAddress;
import java.net.Socket;
import java.security.cert.X509Certificate;
 
/**
 * Desc: 使用Spring RestTemplete实现 Https需要自定义ClientHttpRequestFactory；
 * 

 * 参考链接：https://stackoverflow.com/questions/17619871/access-https-rest-service-using-spring-resttemplate
 */
public class HttpsClientRequestFactory extends SimpleClientHttpRequestFactory {
    @Override
    protected void prepareConnection(HttpURLConnection connection, String httpMethod) {
        try {
            if (!(connection instanceof HttpsURLConnection)) {
                throw new RuntimeException("An instance of HttpsURLConnection is expected");
            }
 
            HttpsURLConnection httpsConnection = (HttpsURLConnection) connection;
 
            TrustManager[] trustAllCerts = new TrustManager[]{
                    new X509TrustManager() {
                        @Override
                        public java.security.cert.X509Certificate[] getAcceptedIssuers() {
                            return null;
                        }
                        @Override
                        public void checkClientTrusted(X509Certificate[] certs, String authType) {
                        }
                        @Override
                        public void checkServerTrusted(X509Certificate[] certs, String authType) {
                        }
 
                    }
            };
            SSLContext sslContext = SSLContext.getInstance("TLS");
            sslContext.init(null, trustAllCerts, new java.security.SecureRandom());
            httpsConnection.setSSLSocketFactory(new MyCustomSSLSocketFactory(sslContext.getSocketFactory()));
 
            httpsConnection.setHostnameVerifier(new HostnameVerifier() {
                @Override
                public boolean verify(String s, SSLSession sslSession) {
                    return true;
                }
            });
 
            super.prepareConnection(httpsConnection, httpMethod);
        } catch (Exception e) {
            e.printStackTrace();
        }
    }
 
    /**
     * We need to invoke sslSocket.setEnabledProtocols(new String[] {"SSLv3"});
     * see http://www.oracle.com/technetwork/java/javase/documentation/cve-2014-3566-2342133.html (Java 8 section)
     */
    private static class MyCustomSSLSocketFactory extends SSLSocketFactory {
 
        private final SSLSocketFactory delegate;
 
        public MyCustomSSLSocketFactory(SSLSocketFactory delegate) {
            this.delegate = delegate;
        }
 
        @Override
        public String[] getDefaultCipherSuites() {
            return delegate.getDefaultCipherSuites();
        }
 
        @Override
        public String[] getSupportedCipherSuites() {
            return delegate.getSupportedCipherSuites();
        }
 
        @Override
        public Socket createSocket(final Socket socket, final String host, final int port, final boolean autoClose) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(socket, host, port, autoClose);
            return overrideProtocol(underlyingSocket);
        }
 
        @Override
        public Socket createSocket(final String host, final int port) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port);
            return overrideProtocol(underlyingSocket);
        }
 
        @Override
        public Socket createSocket(final String host, final int port, final InetAddress localAddress, final int localPort) throws
                IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port, localAddress, localPort);
            return overrideProtocol(underlyingSocket);
        }
 
        @Override
        public Socket createSocket(final InetAddress host, final int port) throws IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port);
            return overrideProtocol(underlyingSocket);
        }
 
        @Override
        public Socket createSocket(final InetAddress host, final int port, final InetAddress localAddress, final int localPort) throws
                IOException {
            final Socket underlyingSocket = delegate.createSocket(host, port, localAddress, localPort);
            return overrideProtocol(underlyingSocket);
        }
 
        private Socket overrideProtocol(final Socket socket) {
            if (!(socket instanceof SSLSocket)) {
                throw new RuntimeException("An instance of SSLSocket is expected");
            }
            ((SSLSocket) socket).setEnabledProtocols(new String[]{"TLSv1"});
            return socket;
        }
    }
}

使用时：

    private RestTemplate restTemplate = new RestTemplate(new HttpsClientRequestFactory());

在构造器中传入工厂类对象。