如何在Android中使用HttpURLConnection类将JSON对象发送到Web服务？

Question

I have Rest Web Service developed using RESTEasy API, that accepts a Json Object and do some processing. I have written two clients for this, An Android Client and a normal Java Program Client. These two are basically the same doing the same function except the connection making part.

I'm using the RESTEasy Connection APIs in the Java Client and HttpURLConnection in the Android app since it is the recommended one (Instead of old Apache HttpClient).

Everything works fine in the Java Client, but it's not the same for the Android App. I'm getting this exception "com.fasterxml.jackson.core.jsonparseexception: unexpected end-of-input" when i run the Android client.

I didn't understand what was wrong so i tried some debug test using Chrome Advanced Rest Client to check whether everything was okay with the Web Service. So i took a copy of the Json String from both clients and executed as a POST request to the web service and it worked perfectly.

And after doing some more testing i assumed that this was because HttpURLConnection connection use an OutputStream to write the data and it sends a binary stream to the endpoint and the web service couldn't read the web service properly. That's all i could think of. (I tested the Json String with Jasonlint tool and they were all valid.)

Can somebody explain me what i'm doing wrong or how to do call the web service properly with HttpURLConnection? Thanks in Advance.

Web Service Code

@Path("/upload")
public class ImageTransferHandler {

@POST
@Path("/jsonString")
@Consumes("application/json")
public Response upload (ImageData jsonString){

    GsonBuilder builder = new GsonBuilder();
    builder.registerTypeAdapter(Image.class, new ImageDeserializer());

    Gson gson = builder.create();

    //Image image = gson.fromJson(jsonString, Image.class);
    ImageData image = jsonString;

    System.out.println("sys out : Name: " + image.getImageName() + " \nEncoded Image String : " + image.getEncodedImageString());

    // Decode the base64 String and get the byte array
    byte[] imageBytes = image.getEncodedImageString().getBytes();

    byte[] decodedBytes = Base64.decodeBase64(imageBytes);

    try {

        // Convert the bytes to an image and store
        ImageConverter ic = new ImageConverter();

        ic.bytesToImage(decodedBytes, "C:\\Users\\yomal.ds\\Desktop\\test\\output.jpg");

    } catch (Exception e) {
        // TODO Auto-generated catch block

        e.printStackTrace();
    }

    try{
        /**
         * Checksum Code Start
         * */
        MessageDigest md1 = MessageDigest.getInstance("SHA-256");
        md1.update(imageBytes);
        byte[] mdbytes1 = md1.digest();

        StringBuffer hexedHashB64 = new StringBuffer();

        for (int i = 0; i < mdbytes1.length; i++) {
            hexedHashB64.append(Integer.toString((mdbytes1[i] & 0xff) + 0x100, 16).substring(1));
        }

        System.out.println("HEXED HASH (Base64) : " + hexedHashB64.toString());
        /**
         * Checksum Code End
         * */


        /**
         * Checksum Code Start
         * */
        MessageDigest md2 = MessageDigest.getInstance("SHA-256");
        md2.update(decodedBytes);
        byte[] mdbytes2 = md2.digest();

        StringBuffer hexedHash = new StringBuffer();

        for (int i = 0; i < mdbytes2.length; i++) {
            hexedHash.append(Integer.toString((mdbytes2[i] & 0xff) + 0x100, 16).substring(1));
        }

        System.out.println("HEXED HASH (Original) : " + hexedHash.toString());
        /**
         * Checksum Code End
         * */

    } catch (NoSuchAlgorithmException e) {
        System.err.println("Algorithm is not correct");
        e.printStackTrace();
    }
    return Response.status(200).entity(image.toString()).build();
}   

}

Android Client Code (Connection Part)

try {
                      Log.e("Upload", "Making connection");
                      String url= "http://192.168.43.2:8080/RestEasyWS/rest/upload/jsonString";
                      URL urlObj = new URL(url);
                      Log.e("Upload", "Opening tunnel");
                      HttpURLConnection con = (HttpURLConnection) urlObj.openConnection();
                      Log.e("Upload", "Tunnel Opened");
                      con.setDoInput(true);
                      con.setDoOutput(true);
                      con.setChunkedStreamingMode(0);
                      con.setRequestProperty("Content-Type", "application/json");
                      con.setRequestProperty("Accept", "application/json");
                      con.setRequestProperty("Accept-Encoding","gzip, deflate");
                      con.setRequestProperty("Accept-Language","en-US,en;q=0.8");
                      con.setRequestMethod("POST");
                      Log.e("Upload", "Connection Made");
                      OutputStreamWriter osw = new OutputStreamWriter(con.getOutputStream());

                      Log.e("Upload", "Uploading...");
                      osw.write(jsonString);
                      Log.e("Upload", "Uploaded...");

                      Log.e("Upload", "Server Response : " + con.getResponseCode() + " - " + con.getResponseMessage() );

                      osw.flush();
                      osw.close();

                  } catch (IOException e) {
                      Log.e("Connection", "Error In Opening a Connection");
                      e.printStackTrace();
                  }

Stack Trace of the Error

Mar 16, 2016 12:16:00 PM org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher processApplication
INFO: RESTEASY002225: Deploying javax.ws.rs.core.Application: class com.informatics.webservice.MessageApplication
Mar 16, 2016 12:16:00 PM org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher processApplication
INFO: RESTEASY002220: Adding singleton resource com.informatics.webservice.imagetransfer.ImageTransferHandler from Application class com.informatics.webservice.MessageApplication
Mar 16, 2016 12:16:04 PM org.jboss.resteasy.core.ExceptionHandler handleFailure
ERROR: RESTEASY002005: Failed executing POST /upload/jsonString
org.jboss.resteasy.spi.ReaderException: com.fasterxml.jackson.databind.JsonMappingException: Unexpected end-of-input in VALUE_STRING
at [Source: org.apache.catalina.connector.CoyoteInputStream@9ceeccd; line: 1, column: 7236430]
at [Source: org.apache.catalina.connector.CoyoteInputStream@9ceeccd; line: 1, column: 23] (through reference chain: com.informatics.webservice.commonobjects.ImageData["encodedImageString"])
at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector.java:184)
at org.jboss.resteasy.core.MethodInjectorImpl.injectArguments(MethodInjectorImpl.java:91)
at org.jboss.resteasy.core.MethodInjectorImpl.invoke(MethodInjectorImpl.java:114)
at org.jboss.resteasy.core.ResourceMethodInvoker.invokeOnTarget(ResourceMethodInvoker.java:295)
at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:249)
at org.jboss.resteasy.core.ResourceMethodInvoker.invoke(ResourceMethodInvoker.java:236)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:395)
at org.jboss.resteasy.core.SynchronousDispatcher.invoke(SynchronousDispatcher.java:202)
at org.jboss.resteasy.plugins.server.servlet.ServletContainerDispatcher.service(ServletContainerDispatcher.java:221)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:56)
at org.jboss.resteasy.plugins.server.servlet.HttpServletDispatcher.service(HttpServletDispatcher.java:51)
at javax.servlet.http.HttpServlet.service(HttpServlet.java:728)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:305)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.tomcat.websocket.server.WsFilter.doFilter(WsFilter.java:51)
at org.apache.catalina.core.ApplicationFilterChain.internalDoFilter(ApplicationFilterChain.java:243)
at org.apache.catalina.core.ApplicationFilterChain.doFilter(ApplicationFilterChain.java:210)
at org.apache.catalina.core.StandardWrapperValve.invoke(StandardWrapperValve.java:222)
at org.apache.catalina.core.StandardContextValve.invoke(StandardContextValve.java:123)
at org.apache.catalina.authenticator.AuthenticatorBase.invoke(AuthenticatorBase.java:502)
at org.apache.catalina.core.StandardHostValve.invoke(StandardHostValve.java:171)
at org.apache.catalina.valves.ErrorReportValve.invoke(ErrorReportValve.java:100)
at org.apache.catalina.valves.AccessLogValve.invoke(AccessLogValve.java:953)
at org.apache.catalina.core.StandardEngineValve.invoke(StandardEngineValve.java:118)
at org.apache.catalina.connector.CoyoteAdapter.service(CoyoteAdapter.java:408)
at org.apache.coyote.http11.AbstractHttp11Processor.process(AbstractHttp11Processor.java:1041)
at org.apache.coyote.AbstractProtocol$AbstractConnectionHandler.process(AbstractProtocol.java:603)
at org.apache.tomcat.util.net.JIoEndpoint$SocketProcessor.run(JIoEndpoint.java:310)
at java.util.concurrent.ThreadPoolExecutor.runWorker(ThreadPoolExecutor.java:1145)
at java.util.concurrent.ThreadPoolExecutor$Worker.run(ThreadPoolExecutor.java:615)
at java.lang.Thread.run(Thread.java:724)
Caused by: com.fasterxml.jackson.databind.JsonMappingException: Unexpected end-of-input in VALUE_STRING
at [Source: org.apache.catalina.connector.CoyoteInputStream@9ceeccd; line: 1, column: 7236430]
at [Source: org.apache.catalina.connector.CoyoteInputStream@9ceeccd; line: 1, column: 23] (through reference chain: com.informatics.webservice.commonobjects.ImageData["encodedImageString"])
at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:339)
at com.fasterxml.jackson.databind.JsonMappingException.wrapWithPath(JsonMappingException.java:299)
at com.fasterxml.jackson.databind.deser.BeanDeserializerBase.wrapAndThrow(BeanDeserializerBase.java:1511)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.vanillaDeserialize(BeanDeserializer.java:262)
at com.fasterxml.jackson.databind.deser.BeanDeserializer.deserialize(BeanDeserializer.java:125)
at com.fasterxml.jackson.databind.ObjectReader._bind(ObjectReader.java:1534)
at com.fasterxml.jackson.databind.ObjectReader.readValue(ObjectReader.java:944)
at org.jboss.resteasy.plugins.providers.jackson.ResteasyJackson2Provider.readFrom(ResteasyJackson2Provider.java:121)
at org.jboss.resteasy.core.interception.AbstractReaderInterceptorContext.readFrom(AbstractReaderInterceptorContext.java:61)
at org.jboss.resteasy.core.interception.ServerReaderInterceptorContext.readFrom(ServerReaderInterceptorContext.java:60)
at org.jboss.resteasy.core.interception.AbstractReaderInterceptorContext.proceed(AbstractReaderInterceptorContext.java:53)
at org.jboss.resteasy.plugins.interceptors.encoding.GZIPDecodingInterceptor.aroundReadFrom(GZIPDecodingInterceptor.java:59)
at org.jboss.resteasy.core.interception.AbstractReaderInterceptorContext.proceed(AbstractReaderInterceptorContext.java:55)
at org.jboss.resteasy.core.MessageBodyParameterInjector.inject(MessageBodyParameterInjector.java:151)
... 30 more

Answer 1

您是否在其他客户端（邮递员）上测试过api，看来您的远程服务器有问题。

Answer 2

Instead of using OutputStreamWriter i used Output Stream and encoded the bytes using UTF-8 charset.

OutputStream os= con.getOutputStream();
os.write(jsonString.getBytes("UTF-8"));
os.flush;
os.close;