commons httpclient - Adding query string parameters to GET POST request

Question

I am using commons HttpClient to make an http call to a Spring servlet  I need to add a few parameters in the query string  So I do the following   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     However when i try to read the parameter in the servlet using    ServletRequestAttributes  RequestContextHolder currentRequestAttributes    getRequest   getParameter  key      it returns null  In fact the parameterMap is completely empty  When I manually append the parameters to the url before creating the HttpGet request  the parameters are available in the servlet  Same when I hit the servlet from the browser using the URL with queryString appended    What s the error here  In httpclient 3 x  GetMethod had a setQueryString   method to append the querystring  What s the equivalent in 4 x

User · Accepted Answer

Here is how you would add query string parameters using HttpClient 4.2 and later:

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

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

The resulting URI would look like:

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

User · Answer

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

User · Answer

The HttpParams interface isn t there for specifying query string parameters  it s for specifying runtime behaviour of the HttpClient object   If you want to pass query string parameters  you need to assemble them on the URL yourself  e g   new HttpGet url    key1     value1           Remember to encode the values first  using URLEncoder

User · Answer

If you want to add a query parameter after you have created the request  try casting the HttpRequest to a HttpBaseRequest  Then you can change the URI of the casted request   HttpGet someHttpGet   new HttpGet  http   google de     URI uri   new URIBuilder someHttpGet getURI    addParameter  q            That was easy    build       HttpRequestBase  someHttpGet  setURI uri

User · Answer

This approach is ok but will not work for when you get params dynamically   sometimes 1  2  3 or more  just like a SOLR search query  for example   Here is a more flexible solution  Crude but can be refined   public static void main String   args         String host    localhost       String port    9093        String param     10-2014 01 description cars amp verbose true amp hl true amp hl simple pre  lt b gt  amp hl simple post  lt  b gt        String   wholeString   param split             String theQueryString   wholeString length  gt  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   amp             List lt String gt  list   Arrays asList paramKeyValuesArray           List lt NameValuePair gt  nvPairList   new ArrayList lt NameValuePair gt             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

User · Answer

This is how I implemented my URL builder  I have created one Service class to provide the params for the URL  public interface ParamsProvider        String queryProvider List lt BasicNameValuePair gt  params        String bodyProvider List lt BasicNameValuePair gt  params        The Implementation of methods are below    Component public class ParamsProviderImp implements ParamsProvider        Override     public String queryProvider List lt BasicNameValuePair gt  params            StringBuilder query   new StringBuilder            AtomicBoolean first   new AtomicBoolean true           params forEach basicNameValuePair - gt                if  first get                      query append                       query append basicNameValuePair toString                     first set false                 else                   query append   amp                     query append basicNameValuePair toString                                       return query toString                Override     public String bodyProvider List lt BasicNameValuePair gt  params            StringBuilder body   new StringBuilder            AtomicBoolean first   new AtomicBoolean true           params forEach basicNameValuePair - gt                if  first get                      body append basicNameValuePair toString                     first set false                 else                   body append   amp                     body append basicNameValuePair toString                                       return body toString               When we need the query params for our URL  I simply call the service and build it  Example for that is below   Class Mock   Autowired ParamsProvider paramsProvider   String url   http   www google lk      For the query params price type  List lt BasicNameValuePair gt  queryParameters   new ArrayList lt  gt      queryParameters add new BasicNameValuePair  price   100     queryParameters add new BasicNameValuePair  type    L     url   url paramsProvider queryProvider queryParameters      You can use it in similar way to send the body params using the bodyProvider

[java] commons httpclient - Adding query string parameters to GET/POST request

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