从NameValuePairs列表创建UrlEncodedFormEntity会抛出NullPointerException
我正在创建一个unit testing来试用我刚刚创建的servlet。
@Test public void test() throws ParseException, IOException { HttpClient client = new DefaultHttpClient(); HttpPost post = new HttpPost("http://localhost:8080/WebService/MakeBaby"); List nameValuePairs = new ArrayList(); nameValuePairs.add(new BasicNameValuePair("father_name", "Foo")); nameValuePairs.add(new BasicNameValuePair("mother_name", "Bar")); post.setEntity(new UrlEncodedFormEntity(nameValuePairs)); HttpResponse response = null; try { response = client.execute(post); } catch (ClientProtocolException e) { e.printStackTrace(); } catch (IOException e) { e.printStackTrace(); } String stringifiedResponse = EntityUtils.toString(response.getEntity()); System.out.println(stringifiedResponse); assertNotNull(stringifiedResponse); }
以下行生成NullPointerException:
post.setEntity(new UrlEncodedFormEntity(nameValuePairs));
有什么我想念的吗?
抱歉这个愚蠢的问题,只需添加utf-8格式即可解决。
post.setEntity(new UrlEncodedFormEntity(nameValuePairs, "utf-8"));
在不传递格式的情况下创建UrlEncodedFormEntity
将使用DEFAULT_CONTENT_CHARSET
,即ISO-8859-1
哪个让我感到困惑…是什么导致它抛出NullPointerException
?
根本不是一个愚蠢的问题。 我认为混淆是在httpclient 4.1中,不需要编码格式 – 这有效:
HttpEntity entity = new UrlEncodedFormEntity(params); method.setEntity(entity);
当我将依赖项更改为httpclient 4.2以访问URIBuilder时 ,我得到了:
java.lang.NullPointerException at org.apache.http.entity.StringEntity.(StringEntity.java:70) at org.apache.http.client.entity.UrlEncodedFormEntity. (UrlEncodedFormEntity.java:78) at org.apache.http.client.entity.UrlEncodedFormEntity. (UrlEncodedFormEntity.java:92)...
使用4.2时,似乎构造函数需要编码,如您所述。 令人困惑的是,doc指定旧构造函数仍然可用,但它似乎不再起作用。
public UrlEncodedFormEntity(List parameters) doc