【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:WindowsSystem32Driversetchosts，添加一行：

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

2. 编辑client端机器的C:WindowsSystem32Driversetclmhosts.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:	omcat.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_HOMEjrelibsecurity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。