HTTP Client in Apache return "Target host must not be null"

Posted on 2009-06-29
Last Modified: 2013-12-06
Dear experts,
I am using Apache HTTP client library for Android emulator.

However whenever I enter e.g "" or "", it always return error "Target host must not be null"
But when i convert into IP Address, all works well.
Would you be able to advice?

public void run() {
			Log.i("GList", "downloadProcess run()");
			props = new Properties();
			try {
				String url;
				url = ""; //THIS IS FAILED
				//url = ""; // THIS IS OK
				HttpManager.doGet(url, props);
			} catch (Exception e) {
				// TODO Auto-generated catch block
			// TODO Auto-generated method stub

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Question by:isuhendro
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LVL 86

Expert Comment

ID: 24743483
>>HttpManager.doGet(url, props);

What's that? It's not Apache HttpClient..

Author Comment

ID: 24743532
HttpManager just a wrapper of Apache HTTP client, please refer to the static method inside HttpManager below.
	public static String doGet (String serviceEndpoint, Properties props) throws Exception
		HttpClient httpClient = new DefaultHttpClient();
		StringBuilder uriBuilder = new StringBuilder(serviceEndpoint);
		StringBuffer sbResponse = new StringBuffer ();		
		Enumeration<Object> enumProps = props.keys();
		String key, value = null;
		if (enumProps.hasMoreElements()) uriBuilder.append('?');
		while (enumProps.hasMoreElements())
			key = (String)enumProps.nextElement();
			value = (String)props.get(key);
		HttpGet request = new HttpGet(uriBuilder.toString());
	HttpResponse response = httpClient.execute(request);

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LVL 86

Accepted Solution

CEHJ earned 125 total points
ID: 24743600
>>But when i convert into IP Address, all works well.

Sounds like a DNS error. Have you tried running your code on another network?

Author Closing Comment

ID: 31598185
hi CEHJ,

thank you for your suggestion.
somehow this line gave invalid form URL
LVL 86

Expert Comment

ID: 24949148

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