commons httpclient - 向GET/POST請求添加查詢字符串參數

Question

我正在使用commons HttpClient對Spring servlet進行http調用。我需要在查詢字符串中添加一些參數。所以，我做到以下幾點：

HttpRequestBase request = new HttpGet(url); 
HttpParams params = new BasicHttpParams(); 
params.setParameter("key1", "value1"); 
params.setParameter("key2", "value2"); 
params.setParameter("key3", "value3"); 
request.setParams(params); 
HttpClient httpClient = new DefaultHttpClient(); 
httpClient.execute(request); 

然而，當我嘗試使用

((ServletRequestAttributes) RequestContextHolder.currentRequestAttributes()).getRequest().getParameter("key"); 

返回null閱讀在servlet的參數。實際上parameterMap是完全空的。當我在創建HttpGet請求之前手動將參數附加到url時，這些參數在servlet中可用。當我使用追加了queryString的URL從瀏覽器中打開servlet時也是如此。

這裏有什麼錯誤？在httpclient 3.x中，GetMethod有一個setQueryString（）方法來追加查詢字符串。 4.x中的等效物是什麼？

Answer 1

這裏是你將如何使用的HttpClient 4.2及更高版本添加查詢字符串參數：

URIBuilder builder = new URIBuilder("http://example.com/"); 
builder.setParameter("parts", "all").setParameter("action", "finish"); 

HttpPost post = new HttpPost(builder.build()); 

產生的URI將如下所示：

http://example.com/?parts=all&action=finish 

Answer 2

HttpParams接口不用於指定查詢字符串參數，它用於指定HttpClient對象的運行時行爲。

如果您想傳遞查詢字符串參數，您需要自己將它們組裝到URL上，例如，

new HttpGet(url + "key1=" + value1 + ...); 

記得先編碼值（使用URLEncoder）。

Answer 3

如果你想添加的查詢參數已創建的請求後，嘗試鑄造HttpRequest到HttpBaseRequest。然後你可以改變鑄造請求的URI：

HttpGet someHttpGet = new HttpGet("http://google.de"); 

URI uri = new URIBuilder(someHttpGet.getURI()).addParameter("q", 
     "That was easy!").build(); 

((HttpRequestBase) someHttpGet).setURI(uri); 

Answer 4

這種方法是可以的，但不適用於動態獲取參數，有時爲1，2，3或更多，就像SOLR搜索查詢（例如）

這是一個更靈活的解決方案。原油，但可以提煉。

public static void main(String[] args) { 

    String host = "localhost"; 
    String port = "9093"; 

    String param = "/10-2014.01?description=cars&verbose=true&hl=true&hl.simple.pre=<b>&hl.simple.post=</b>"; 
    String[] wholeString = param.split("\\?"); 
    String theQueryString = wholeString.length > 1 ? wholeString[1] : ""; 

    String SolrUrl = "http://" + host + ":" + port + "/mypublish-services/carclassifications/" + "loc"; 

    GetMethod method = new GetMethod(SolrUrl); 

    if (theQueryString.equalsIgnoreCase("")) { 
     method.setQueryString(new NameValuePair[]{ 
     }); 
    } else { 
     String[] paramKeyValuesArray = theQueryString.split("&"); 
     List<String> list = Arrays.asList(paramKeyValuesArray); 
     List<NameValuePair> nvPairList = new ArrayList<NameValuePair>(); 
     for (String s : list) { 
      String[] nvPair = s.split("="); 
      String theKey = nvPair[0]; 
      String theValue = nvPair[1]; 
      NameValuePair nameValuePair = new NameValuePair(theKey, theValue); 
      nvPairList.add(nameValuePair); 
     } 
     NameValuePair[] nvPairArray = new NameValuePair[nvPairList.size()]; 
     nvPairList.toArray(nvPairArray); 
     method.setQueryString(nvPairArray);  // Encoding is taken care of here by setQueryString 

    } 
} 

Answer 5

I am using httpclient 4.4. For solr query I used the following way and it worked. 

NameValuePair nv2 = new BasicNameValuePair("fq","(active:true) AND (category:Fruit OR category1:Vegetable)"); 
nvPairList.add(nv2); 
NameValuePair nv3 = new BasicNameValuePair("wt","json"); 
nvPairList.add(nv3); 
NameValuePair nv4 = new BasicNameValuePair("start","0"); 
nvPairList.add(nv4); 
NameValuePair nv5 = new BasicNameValuePair("rows","10"); 
nvPairList.add(nv5); 

HttpClient client = HttpClientBuilder.create().build(); 
HttpGet request = new HttpGet(url); 
URI uri = new URIBuilder(request.getURI()).addParameters(nvPairList).build(); 
      request.setURI(uri); 

HttpResponse response = client.execute(request);  
if (response.getStatusLine().getStatusCode() != 200) { 

} 

BufferedReader br = new BufferedReader(
          new InputStreamReader((response.getEntity().getContent()))); 

String output; 
System.out.println("Output .... "); 
String respStr = ""; 
while ((output = br.readLine()) != null) { 
    respStr = respStr + output; 
    System.out.println(output); 
}