UnknownHostException尝试通过Ektorp连接到云数据库

Question

这并不是在点击如何使用Ektorp连接到托管的云数据库。我在Eclipse中通过新的m2eclipse Maven集成使用Ektorp1.1(这很不错)。我正在努力寻找除了javadoc之外的好的CouchDB/Cloudant/Ektorp文档。

我正在尝试从他们的main page中获取示例Ektorp API示例：

HttpClient httpClient = new StdHttpClient.Builder()
                                    .host("localhost")
                                    .port(5984)
                                    .build();

CouchDbInstance dbInstance = new StdCouchDbInstance(httpClient);
CouchDbConnector db = new StdCouchDbConnector("mydatabase", dbInstance);

db.createDatabaseIfNotExists();

我用什么来构建httpClient并不重要，我总是得到下面的UnknownHostException错误。我已经为主机尝试了这些URL: https/http://cloudant.com/db/_session和https/http://[username].cloudant.com

那么端口号呢？用户名和密码是否应该包含在StdHttpClient.Builder()中？

下面是完整的错误-它在createDatabaseIfNotExists()调用中失败，但我不确定CouchDbConnector变量是否正确。

Exception in thread "main" org.ektorp.DbAccessException: java.net.UnknownHostException: https://cloudant.com/db/_session
    at org.ektorp.util.Exceptions.propagate(Exceptions.java:19)
    at org.ektorp.http.StdHttpClient.executeRequest(StdHttpClient.java:104)
    at org.ektorp.http.StdHttpClient.get(StdHttpClient.java:42)
    at org.ektorp.http.RestTemplate.get(RestTemplate.java:21)
    at org.ektorp.impl.StdCouchDbInstance.getAllDatabases(StdCouchDbInstance.java:61)
    at org.ektorp.impl.StdCouchDbConnector.createDatabaseIfNotExists(StdCouchDbConnector.java:256)
    at com.codegouge.examples.App.main(App.java:30)
Caused by: java.net.UnknownHostException: https://cloudant.com/db/_session
    at java.net.Inet6AddressImpl.lookupAllHostAddr(Native Method)
    at java.net.InetAddress$1.lookupAllHostAddr(InetAddress.java:850)
    at java.net.InetAddress.getAddressFromNameService(InetAddress.java:1201)
    at java.net.InetAddress.getAllByName0(InetAddress.java:1154)
    at java.net.InetAddress.getAllByName(InetAddress.java:1084)
    at java.net.InetAddress.getAllByName(InetAddress.java:1020)
    at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:126)
    at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:149)
    at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:108)
    at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:415)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:641)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:576)
    at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:554)
    at org.ektorp.http.StdHttpClient.executeRequest(StdHttpClient.java:96)

Answer 1

我对Ektorp不是很熟悉，但你肯定需要把你的用户名/密码放进去。我建议使用以下代码创建HttpClient：

HttpClient httpClient = new StdHttpClient.Builder()
                                    .host("[username].cloudant.com")
                                    .port(443)
                                    .username("[username]")
                                    .password("[password]")
                                    .build();

我已将端口更改为443 ( Cloudant监听的HTTPS的默认端口)，并添加了用户名和密码。我没有看到任何方法让Ektorp知道你想使用HTTPS，但幸运的是，这将在内部处理。

Answer 2

所以我做错了几件事。使用SSL requires additional parameters。另外，将Ektorp 1.1.1 includes SSL-related bug fixes设置为1.1.0。这是我的最后一个HttpClient构造函数：

HttpClient httpClient = new StdHttpClient.Builder()
        .host("[username].cloudant.com")
        .port(443)
        .username("[username]")
        .password("[password]")
        .enableSSL(true)
        .relaxedSSLSettings(true)
        .build();

此外，请确保在pom.xml中更新ektorp的依赖项以查找版本"1.1.1“。如果有兴趣，我有一篇博客文章介绍了这个练习here。

Answer 3

您还可以使用URL与Ektorp连接：

JSONObject serviceAttr = val.getJSONObject(0);
                        JSONObject credentials = serviceAttr.getJSONObject("credentials");
                        httpClient = new StdHttpClient.Builder()
                        .url(credentials.getString("url"))
                        .build();

这是一种简单的连接方式。我找到了一个使用Ektorp 1.4.2：http://www.ibm.com/developerworks/java/library/j-hangman-app/index.html进行连接的教程