【Tech】CAS多机部署Server和Java Client端

昨天尝试把cas的java client端部署到另外一台机器，结果就有问题了。（localhost部署cas server和java client端参见：http://www.cnblogs.com/sunshineatnoon/p/4119565.html）

主要是client访问的时候报错：javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: No subject alternative names present。

后来在stackoverflow上找到了解决办法：http://stackoverflow.com/questions/9331087/how-to-setup-ssl-for-cas-and-client-different-machines?rq=1

根据jasig文档对这个错误的解释：

Sample Alt Name Stack Trace
javax.net.ssl.SSLHandshakeException: java.security.cert.CertificateException: No subject alternative names present
In most cases this is a hostname/SSL certificate CN mismatch. This commonly happens when a self-signed certificate issued to localhost is placed on a machine that is accessed by IP address. It should be noted that generating a certificate with an IP address for a common name, e.g. CN=192.168.1.1,OU=Middleware,dc=vt,dc=edu, will not work in most cases where the client making the connection is Java. For example the Java CAS client will throw SSL errors on connecting to a CAS server secured with a certificate containing an IP address in the CN.

是由于生成的证书中域名（CN）和server的域名或者以后client端访问的域名不一致造成的，并且这里也说了，不能用ip地址当作生成证书时候的CN，只能用域名。

所以改变的方法就是用域名生成证书，并且配置client端电脑的hosts和lmhosts.sam文件解析服务器域名，具体步骤如下：

1. 编辑client端机器的C:\Windows\System32\Drivers\etc\hosts，添加一行：

your_ip(xxx.xxx.xxx.xxx) your_cn(sunshineatnoon.com)

2. 编辑client端机器的C:\Windows\System32\Drivers\etc\lmhosts.sam，添加一行：

your_ip(xxx.xxx.xxx.xxx) your_cn(sunshineatnoon.com)

3. 在server端所在的机器用keytool重新生成证书：

keytool -genkeypair -alias "tomcat" -keyalg "RSA" -keystore "g:\tomcat.keystore"

在回答"what's you name?"这个问题的时候回答上述你的域名：sunshineatnoon.com

4.配置server端机器的tomcat下%TOMCAT_PATH%/conf下的server.xml文件，参考http://www.cnblogs.com/sunshineatnoon/p/4064632.html的3(1)(2)，如果生成证书和以前的位置密码都没变，就不用重新配置了。

5.重新用文件InstallCert.java生成证书放到client端机器的$JAVA_HOME\jre\lib\security下，参考http://www.cnblogs.com/sunshineatnoon/p/4070750.html我所解决的第2个bug。

6.client端的java程序中请求ticket的url就由https://localhost:8443/cas/v1/tickets变成了https://sunshineatnoon.com:8443/cas/v1/tickets，改变后的client.java如下所示：

 package cas;

 import java.io.BufferedReader;
 import java.io.BufferedWriter;
 import java.io.IOException;
 import java.io.InputStreamReader;
 import java.io.OutputStreamWriter;
 import java.net.MalformedURLException;
 import java.net.URL;
 import java.net.URLConnection;
 import java.net.URLEncoder;

 import javax.net.ssl.HttpsURLConnection;

 public class Client {

     public static void main(String... args) throws Exception
     {
         String username ="test01";
         String password ="psw01";
         validateFromCAS(username,password);
     }

     public static boolean validateFromCAS(String username, String password) throws Exception
     {

         //String url = "https://localhost:8443/cas/v1/tickets";
         String url = "https://sunshineatnoon.com:8443/cas/v1/tickets";
         try
         {
             HttpsURLConnection hsu = (HttpsURLConnection)openConn(url);
             String s =   URLEncoder.encode("username","UTF-8") + "=" + URLEncoder.encode("test01","UTF-8");
             s+="&" +URLEncoder.encode("password","UTF-8") + "=" + URLEncoder.encode("psw01","UTF-8");

             System.out.println(s);
             OutputStreamWriter out = new OutputStreamWriter(hsu.getOutputStream());
             BufferedWriter bwr = new BufferedWriter(out);
             bwr.write(s);
             bwr.flush();
             bwr.close();
             out.close();

             String tgt = hsu.getHeaderField("location");
             System.out.println( hsu.getResponseCode());
             if(tgt != null && hsu.getResponseCode() == 201)
             {
                 System.out.println(tgt);

                 System.out.println("Tgt is : " + tgt.substring( tgt.lastIndexOf("/") +1));
                 tgt = tgt.substring( tgt.lastIndexOf("/") +1);
                 bwr.close();
                 closeConn(hsu);

                 //String serviceURL = "http://localhost:8080/CasClient";
                 String serviceURL = "http://www.baidu.com";
                 String encodedServiceURL = URLEncoder.encode("service","utf-8") +"=" + URLEncoder.encode(serviceURL,"utf-8");
                 System.out.println("Service url is : " + encodedServiceURL);

                 String myURL = url+ "/"+ tgt ;
                 System.out.println(myURL);
                 hsu = (HttpsURLConnection)openConn(myURL);
                 out = new OutputStreamWriter(hsu.getOutputStream());
                 bwr = new BufferedWriter(out);
                 bwr.write(encodedServiceURL);
                 bwr.flush();
                 bwr.close();
                 out.close();

                 System.out.println("Response code is:  " + hsu.getResponseCode());

                 BufferedReader isr = new BufferedReader(   new InputStreamReader(hsu.getInputStream()));
                 String line;
                 System.out.println( hsu.getResponseCode());
                 while ((line = isr.readLine()) != null) {
                     System.out.println( line);
                 }
                 isr.close();
                 hsu.disconnect();
                 return true;

             }
             else
             {
                 return false;
             }

         }
         catch(MalformedURLException mue)
         {
             mue.printStackTrace();
             throw mue; 

         }
         catch(IOException ioe)
         {
             ioe.printStackTrace();
             throw ioe;
         }

     }

     static URLConnection openConn(String urlk)  throws MalformedURLException, IOException
     {

         URL url = new URL(urlk);
         HttpsURLConnection hsu = (HttpsURLConnection) url.openConnection();
         hsu.setDoInput(true);
         hsu.setDoOutput(true);
         hsu.setRequestMethod("POST");
         return hsu;

     }

     static void closeConn(HttpsURLConnection c)
     {
         c.disconnect();
     }

     }

注意红色那行改变的代码。

7.这时client端上的java client端应该就可以成功得到TGT和ST了。