Java加载证书，访问https链接，报了个错这是什么意思呢

Question

public static void main( String[] args ){
	PrintWriter out = null;
    BufferedReader in = null;
    String result = "";
    //设置证书
    System.setProperty("javax.net.ssl.trustStore","D:\Program Files\Java\jdk1.7.0_79\bin\12306d.keystore");  
    System.setProperty("javax.net.ssl.trustStorePassword", "12306java");  
    try {
        URL realUrl = new URL("https://kyfw.12306.cn/otn/login/loginAysnSuggest");
        // 打开和URL之间的连接
        URLConnection conn = realUrl.openConnection();
        // 设置通用的请求属性
        conn.setRequestProperty("accept", "*/*");
        conn.setRequestProperty("connection", "Keep-Alive");
        conn.setRequestProperty("user-agent",
                "Mozilla/4.0 (compatible; MSIE 6.0; Windows NT 5.1;SV1)");
        // 发送POST请求必须设置如下两行
        conn.setDoOutput(true);
        conn.setDoInput(true);
        // 获取URLConnection对象对应的输出流
        out = new PrintWriter(conn.getOutputStream());
        // 发送请求参数
        out.print("loginUserDTO.user_name=aaa&userDTO.password=123456&randCode=182,51,19,130");
        // flush输出流的缓冲
        out.flush();
        // 定义BufferedReader输入流来读取URL的响应
        in = new BufferedReader(
                new InputStreamReader(conn.getInputStream()));
        String line;
        while ((line = in.readLine()) != null) {
            result += line;
        }
        System.out.println(result);
    } catch (Exception e) {
        System.out.println("发送 POST 请求出现异常！"+e);
        e.printStackTrace();
    }
    //使用finally块来关闭输出流、输入流
    finally{
        try{
            if(out!=null){
                out.close();
            }
            if(in!=null){
                in.close();
            }
        }
        catch(IOException ex){
            ex.printStackTrace();
        }
    }
}

 

 

这是什么错呢

 

发送 POST 请求出现异常！javax.net.ssl.SSLException: java.lang.RuntimeException: Unexpected error: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty
javax.net.ssl.SSLException: java.lang.RuntimeException: Unexpected error: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty
    at sun.security.ssl.Alerts.getSSLException(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.fatal(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.handleException(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.startHandshake(Unknown Source)
    at sun.net.www.protocol.https.HttpsClient.afterConnect(Unknown Source)
    at sun.net.www.protocol.https.AbstractDelegateHttpsURLConnection.connect(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.getOutputStream0(Unknown Source)
    at sun.net.www.protocol.http.HttpURLConnection.getOutputStream(Unknown Source)
    at sun.net.www.protocol.https.HttpsURLConnectionImpl.getOutputStream(Unknown Source)
    at jj.myclic.main(myclic.java:40)
Caused by: java.lang.RuntimeException: Unexpected error: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty
    at sun.security.validator.PKIXValidator.<init>(Unknown Source)
    at sun.security.validator.Validator.getInstance(Unknown Source)
    at sun.security.ssl.X509TrustManagerImpl.getValidator(Unknown Source)
    at sun.security.ssl.X509TrustManagerImpl.checkTrustedInit(Unknown Source)
    at sun.security.ssl.X509TrustManagerImpl.checkTrusted(Unknown Source)
    at sun.security.ssl.X509TrustManagerImpl.checkServerTrusted(Unknown Source)
    at sun.security.ssl.ClientHandshaker.serverCertificate(Unknown Source)
    at sun.security.ssl.ClientHandshaker.processMessage(Unknown Source)
    at sun.security.ssl.Handshaker.processLoop(Unknown Source)
    at sun.security.ssl.Handshaker.process_record(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.readRecord(Unknown Source)
    at sun.security.ssl.SSLSocketImpl.performInitialHandshake(Unknown Source)
    ... 8 more
Caused by: java.security.InvalidAlgorithmParameterException: the trustAnchors parameter must be non-empty
    at java.security.cert.PKIXParameters.setTrustAnchors(Unknown Source)
    at java.security.cert.PKIXParameters.<init>(Unknown Source)
    at java.security.cert.PKIXBuilderParameters.<init>(Unknown Source)
    ... 20 more