How can I get an HTTP response body as a string

Question

I know there used to be a way to get it with Apache Commons as documented here  http   hc apache org httpclient-legacy apidocs org apache commons httpclient HttpMethod html    and an example here  http   www kodejava org examples 416 html    but I believe this is deprecated  Is there any other way to make an http get request in Java and get the response body as a string and not a stream

User · Answer

This is relatively simple in the specific case, but quite tricky in the general case.

HttpClient httpclient = new DefaultHttpClient();
HttpGet httpget = new HttpGet("http://stackoverflow.com/");
HttpResponse response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
System.out.println(EntityUtils.getContentMimeType(entity));
System.out.println(EntityUtils.getContentCharSet(entity));

The answer depends on the Content-Type HTTP response header.

This header contains information about the payload and might define the encoding of textual data. Even if you assume text types, you may need to inspect the content itself in order to determine the correct character encoding. E.g. see the HTML 4 spec for details on how to do that for that particular format.

Once the encoding is known, an InputStreamReader can be used to decode the data.

This answer depends on the server doing the right thing - if you want to handle cases where the response headers don't match the document, or the document declarations don't match the encoding used, that's another kettle of fish.

User · Answer

Below is a simple way of accessing the response as a String using Apache HTTP Client library   import org apache http HttpResponse  import org apache http client HttpClient  import org apache http client ResponseHandler  import org apache http client methods HttpGet  import org apache http impl client BasicResponseHandler           HttpGet get  HttpClient httpClient      initialize variables above  ResponseHandler lt String gt  responseHandler   new BasicResponseHandler    String responseBody   httpClient execute get  responseHandler

User · Answer

Following is the code snippet which shows better way to handle the response body as a String whether it s a valid response or error response for the HTTP POST request   BufferedReader reader   null  OutputStream os   null  String payload       try       URL url1   new URL  YOUR URL        HttpURLConnection postConnection    HttpURLConnection  url1 openConnection        postConnection setRequestMethod  POST        postConnection setRequestProperty  Content-Type    application json        postConnection setDoOutput true       os   postConnection getOutputStream        os write eventContext getMessage   getPayloadAsString   getBytes         os flush         String line      try          reader   new BufferedReader new InputStreamReader postConnection getInputStream                catch IOException e           if reader    null              reader   new BufferedReader new InputStreamReader postConnection getErrorStream                while   line   reader readLine       null          payload    line toString             catch  Exception ex                log error  Post request Failed with message      ex getMessage    ex     finally       try           reader close            os close          catch  IOException e            log error e getMessage    e           return null

User · Answer

We can use the below code also to get the HTML Response in java  import org apache http client HttpClient  import org apache http client methods HttpGet  import org apache http impl client DefaultHttpClient  import org apache http HttpResponse  import java io BufferedReader  import java io InputStreamReader  import org apache log4j Logger   public static void main String   args  throws Exception       HttpClient client   new DefaultHttpClient            args 0   -  http   hostname 8080 abc xyz CheckResponse     HttpGet request1   new HttpGet args 0        HttpResponse response1   client execute request1       int code   response1 getStatusLine   getStatusCode         try  BufferedReader br   new BufferedReader new InputStreamReader  response1 getEntity   getContent                     Read in all of the post results into a String          String output               Boolean keepGoing   true          while  keepGoing                String currentLine   br readLine                 if  currentLine    null                    keepGoing   false                else                   output    currentLine                                   System out println  Response-- gt     output         catch  Exception e            System out println  Exception    e

User · Answer

You can use a 3-d party library that sends Http request and handles the response  One of the well-known products would be Apache commons HTTPClient  HttpClient javadoc  HttpClient Maven artifact  There is by far less known but much simpler HTTPClient  part of an open source MgntUtils library written by me   MgntUtils HttpClient javadoc   MgntUtils maven artifact  MgntUtils Github  Using either of those libraries you can send your REST request and receive response independently from Spring as part of your business logic

User · Answer

The Answer by McDowell is correct one  However if you try other suggestion in few of the posts above   HttpEntity responseEntity   httpResponse getEntity    if responseEntity  null       response   EntityUtils toString responseEntity      S O P  response       Then it will give you illegalStateException stating that content is already consumed

User · Answer

Here s a lightweight way to do so   String responseString       for  int i   0  i  lt  response getEntity   getContentLength    i           responseString        Character toString  char response getEntity   getContent   read          With of course responseString containing website s response and response being type of HttpResponse  returned by HttpClient execute request

User · Answer

Here s an example from another simple project I was working on using the httpclient library from Apache   String response   new String    List lt NameValuePair gt  nameValuePairs   new ArrayList lt NameValuePair gt  1   nameValuePairs add new BasicNameValuePair  j   request    HttpEntity requestEntity   new UrlEncodedFormEntity nameValuePairs    HttpPost httpPost   new HttpPost mURI   httpPost setEntity requestEntity   HttpResponse httpResponse   mHttpClient execute httpPost   HttpEntity responseEntity   httpResponse getEntity    if responseEntity  null        response   EntityUtils toString responseEntity       just use EntityUtils to grab the response body as a String   very simple

User · Answer

If you are using Jackson to deserialize the response body  one very simple solution is to use request getResponseBodyAsStream   instead of request getResponseBodyAsString

User · Answer

Every library I can think of returns a stream  You could use IOUtils toString   from Apache Commons IO to read an InputStream into a String in one method call  E g    URL url   new URL  http   www example com     URLConnection con   url openConnection    InputStream in   con getInputStream    String encoding   con getContentEncoding    encoding   encoding    null    UTF-8    encoding  String body   IOUtils toString in  encoding   System out println body     Update  I changed the example above to use the content encoding from the response if available  Otherwise it ll default to UTF-8 as a best guess  instead of using the local system default

User · Answer

Here are two examples from my working project     Using EntityUtils and HttpEntity  HttpResponse response   httpClient execute new HttpGet URL    HttpEntity entity   response getEntity    String responseString   EntityUtils toString entity   UTF-8    System out println responseString    Using BasicResponseHandler  HttpResponse response   httpClient execute new HttpGet URL    String responseString   new BasicResponseHandler   handleResponse response   System out println responseString

User · Answer

How about just this   org apache commons io IOUtils toString new URL  http   www someurl com

User · Answer

Here is a vanilla Java answer  import java net http HttpClient  import java net http HttpResponse  import java net http HttpRequest  import java net http HttpRequest BodyPublishers       HttpClient client   HttpClient newHttpClient    HttpRequest request   HttpRequest newBuilder      uri targetUrl     header  quot Content-Type quot    quot application json quot      POST BodyPublishers ofString requestBody      build    HttpResponse response   client send request  HttpResponse BodyHandlers ofString     String responseString    String  response body

[java] How can I get an HTTP response body as a string?

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