关于JAVA发送Https请求（HttpsURLConnection和HttpURLConnection）

关于JAVA发送Https请求（HttpsURLConnection和HttpURLConnection）

【转】

https协议对于开发者而言其实只是多了一步证书验证的过程。这个证书正常情况下被jdk/jre/security/cacerts所管理。里面证书包含两种情况：

1、机构所颁发的被认证的证书，这种证书的网站在浏览器访问时https头显示为绿色如百度

2、个人所设定的证书，这种证书的网站在浏览器里https头显示为红色×，且需要点击信任该网站才能继续访问。而点击信任这一步的操作就是我们在java代码访问https网站时区别于http请求需要做的事情。

所以JAVA发送Https请求有两种情况，三种解决办法：

第一种情况：Https网站的证书为机构所颁发的被认证的证书，这种情况下和http请求一模一样，无需做任何改变，用HttpsURLConnection或者HttpURLConnection都可以

• public static void main(String[] args) throws Exception{
          URL serverUrl = new URL("https://xxxx");
          HttpURLConnection conn = (HttpURLConnection) serverUrl.openConnection();
          conn.setRequestMethod("GET");
          conn.setRequestProperty("Content-type", "application/json");
          //必须设置false，否则会自动redirect到重定向后的地址
          conn.setInstanceFollowRedirects(false);
          conn.connect();
          String result = getReturn(conn);
      }
  
      /*请求url获取返回的内容*/
      public static String getReturn(HttpURLConnection connection) throws IOException{
          StringBuffer buffer = new StringBuffer();
          //将返回的输入流转换成字符串
          try(InputStream inputStream = connection.getInputStream();
              InputStreamReader inputStreamReader = new InputStreamReader(inputStream, ConstantInfo.CHARSET);
              BufferedReader bufferedReader = new BufferedReader(inputStreamReader);){
              String str = null;
              while ((str = bufferedReader.readLine()) != null) {
                  buffer.append(str);
              }
              String result = buffer.toString();
              return result;
          }
  }

第二种情况：个人所设定的证书，这种证书默认不被信任，需要我们自己选择信任，信任的办法有两种：

A、将证书导入java的运行环境中

• 从该网站下载或者从网站开发者出获取证书cacert.crt
• 运行命令将证书导入java运行环境：keytool -import -keystore %JAVA_HOME%\jre\lib\security\cacerts -file cacert.crt -alias xxx
• 完成。java代码中发送https的请求和http一样，同第一种情况。

B、忽略证书验证过程，忽略之后任何Https协议网站皆能正常访问，同第一种情况

• import java.security.cert.CertificateException;
  import java.security.cert.X509Certificate;
  import javax.net.ssl.X509TrustManager;
  public class MyX509TrustManager implements X509TrustManager {
  
      @Override
      public void checkClientTrusted(X509Certificate certificates[],String authType) throws CertificateException {
      }
  
      @Override
      public void checkServerTrusted(X509Certificate[] ax509certificate,String s) throws CertificateException {
      }
  
      @Override
      public X509Certificate[] getAcceptedIssuers() {
          // TODO Auto-generated method stub
          return null;
      }
  }

• public static void main(String[] args) throws Exception{
          SSLContext sslcontext = SSLContext.getInstance("SSL","SunJSSE");
          sslcontext.init(null, new TrustManager[]{new MyX509TrustManager()}, new java.security.SecureRandom());
          URL url = new URL("https://xxxx");
          HostnameVerifier ignoreHostnameVerifier = new HostnameVerifier() {
              public boolean verify(String s, SSLSession sslsession) {
                  System.out.println("WARNING: Hostname is not matched for cert.");
                  return true;
              }
          };
          HttpsURLConnection.setDefaultHostnameVerifier(ignoreHostnameVerifier);
          HttpsURLConnection.setDefaultSSLSocketFactory(sslcontext.getSocketFactory());
          //之后任何Https协议网站皆能正常访问，同第一种情况
  }

C、java代码中加载证书，必须使用HttpsURLConnection方式

• 从网站开发者出获取生成证书的密钥库cacert.keystore

• import java.io.FileInputStream;
  import java.security.KeyStore;
  import java.security.cert.CertificateException;
  import java.security.cert.X509Certificate;
  import javax.net.ssl.TrustManager;
  import javax.net.ssl.TrustManagerFactory;
  import javax.net.ssl.X509TrustManager;
  public class MyX509TrustManager implements X509TrustManager {
      /*
       * The default X509TrustManager returned by SunX509.  We'll delegate
       * decisions to it, and fall back to the logic in this class if the
       * default X509TrustManager doesn't trust it.
       */
      X509TrustManager sunJSSEX509TrustManager;
      MyX509TrustManager() throws Exception {
          // create a "default" JSSE X509TrustManager.
          KeyStore ks = KeyStore.getInstance("JKS");
          ks.load(new FileInputStream("cancert.keystore"),
                  "changeit".toCharArray());
          TrustManagerFactory tmf =
                  TrustManagerFactory.getInstance("SunX509", "SunJSSE");
          tmf.init(ks);
          TrustManager tms [] = tmf.getTrustManagers();
              /*
               * Iterate over the returned trustmanagers, look
               * for an instance of X509TrustManager.  If found,
               * use that as our "default" trust manager.
               */
          for (int i = 0; i < tms.length; i++) {
              if (tms[i] instanceof X509TrustManager) {
                  sunJSSEX509TrustManager = (X509TrustManager) tms[i];
                  return;
              }
          }
              /*
               * Find some other way to initialize, or else we have to fail the
               * constructor.
               */
          throw new Exception("Couldn't initialize");
      }
      /*
       * Delegate to the default trust manager.
       */
      public void checkClientTrusted(X509Certificate[] chain, String authType)
              throws CertificateException {
          try {
              sunJSSEX509TrustManager.checkClientTrusted(chain, authType);
          } catch (CertificateException excep) {
              // do any special handling here, or rethrow exception.
          }
      }
      /*
       * Delegate to the default trust manager.
       */
      public void checkServerTrusted(X509Certificate[] chain, String authType)
              throws CertificateException {
          try {
              sunJSSEX509TrustManager.checkServerTrusted(chain, authType);
          } catch (CertificateException excep) {
                  /*
                   * Possibly pop up a dialog box asking whether to trust the
                   * cert chain.
                   */
          }
      }
      /*
       * Merely pass this through.
       */
      public X509Certificate[] getAcceptedIssuers() {
          return sunJSSEX509TrustManager.getAcceptedIssuers();
      }
  }

• public static void main(String[] args) throws Exception{
          SSLContext sslcontext = SSLContext.getInstance("SSL","SunJSSE");
          sslcontext.init(null, new TrustManager[]{new MyX509TrustManager()}, new java.security.SecureRandom());
          URL serverUrl = new URL("https://xxxx");
          HttpsURLConnection conn = (HttpsURLConnection) serverUrl.openConnection();
          conn.setSSLSocketFactory(sslcontext.getSocketFactory());
          conn.setRequestMethod("GET");
          conn.setRequestProperty("Content-type", "application/json");
          //必须设置false，否则会自动redirect到重定向后的地址
          conn.setInstanceFollowRedirects(false);
          conn.connect();
          String result = getReturn(conn);
      }
  
      /*请求url获取返回的内容*/
      public static String getReturn(HttpsURLConnection connection) throws IOException{
          StringBuffer buffer = new StringBuffer();
          //将返回的输入流转换成字符串
          try(InputStream inputStream = connection.getInputStream();
              InputStreamReader inputStreamReader = new InputStreamReader(inputStream, ConstantInfo.CHARSET);
              BufferedReader bufferedReader = new BufferedReader(inputStreamReader);){
              String str = null;
              while ((str = bufferedReader.readLine()) != null) {
                  buffer.append(str);
              }
              String result = buffer.toString();
              return result;
          }
  }