Java REST helper methods. Requires Gson for serialization to/deserialization from json.

DotNetDateJsonDeserializer.java

package com.kyzog.android;

import java.lang.reflect.Type;
import java.util.Date;

import com.google.gson.JsonDeserializationContext;
import com.google.gson.JsonDeserializer;
import com.google.gson.JsonElement;
import com.google.gson.JsonParseException;

public class DotNetDateJsonDeserializer implements JsonDeserializer<Date> {

	public Date deserialize(JsonElement json, Type typeOfT, JsonDeserializationContext context) throws JsonParseException { 
		String jsonString = json.getAsJsonPrimitive().getAsString();
		if(jsonString != null) {
			jsonString = jsonString.replace("/Date(", "");
			int indexOfTimeZone = jsonString.indexOf("+");
			if (indexOfTimeZone < 0){
				indexOfTimeZone = jsonString.indexOf("-");
			}
			if(indexOfTimeZone > -1){
				jsonString = jsonString.substring(0, indexOfTimeZone);
			}
				
			jsonString = jsonString.replace(")/", "");
		}
		return new Date(Long.valueOf(jsonString));
	}
}

RestHelper.java

package com.kyzog.android;

import java.io.IOException;
import java.io.InputStream;
import java.net.HttpURLConnection;
import java.net.URL;
import java.net.URLConnection;
import java.util.Date;

import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.client.methods.HttpUriRequest;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.DefaultHttpClient;
import org.apache.http.util.EntityUtils;


import android.util.Base64;
import com.google.gson.FieldNamingPolicy;
import com.google.gson.Gson;
import com.google.gson.GsonBuilder;

public class RestHelper {

	public static <OutT extends Object> OutT PerformRequest(String url, String userName, String password, Object payload, HttpMethod method, Boolean keepAlive, Class<OutT> outputClass) 
			throws Exception {
		OutT returnValue = null;
		Gson gson = new GsonBuilder()
				.registerTypeAdapter(Date.class,
						new DotNetDateJsonDeserializer())
				.setFieldNamingPolicy(FieldNamingPolicy.UPPER_CAMEL_CASE)
				.create();

		DefaultHttpClient client = new DefaultHttpClient();
		HttpUriRequest methodEntity = null;
		StringEntity payloadEntity;

		switch (method) {
		case DELETE:
			break;
		case GET:
			HttpGet get = new HttpGet(url);
			methodEntity = get;
			break;
		case POST:
			HttpPost post = new HttpPost(url);
			payloadEntity = new StringEntity(gson.toJson(payload));
			payloadEntity.setContentType("application/json");
			post.setEntity(payloadEntity);
			methodEntity = post;
			break;
		case PUT:
			HttpPut put = new HttpPut(url);
			payloadEntity = new StringEntity(gson.toJson(payload));
			payloadEntity.setContentType("application/json");
			put.setEntity(payloadEntity);
			methodEntity = put;
			break;
		}

		methodEntity.addHeader(
				"Authorization",
				"Basic "
						+ Base64.encodeToString(
								(userName + ":" + password).getBytes(),
								Base64.NO_WRAP));
		String responsePayload = "";
		try {
			HttpResponse response = client.execute(methodEntity);
			HttpEntity responseEntity = response.getEntity();
			responsePayload = EntityUtils.toString(responseEntity);
			returnValue = (OutT) gson.fromJson(responsePayload, outputClass);
			return returnValue;
		} catch (Exception e) {
			throw new Exception("There was an error performing a REST call\r\nResponsePayload: " + responsePayload, e);
		}
	}

	public static InputStream PerformStreamRequest(String url, String userName, String password)
			throws IOException {
		InputStream returnValue = null;
		
		String authString = userName+":"+password;
		String base64 = Base64.encodeToString(authString.getBytes(), 0);

		URL urlObject = new URL(url);
		URLConnection urlConn = urlObject.openConnection();
		urlConn.setRequestProperty("Authorization", "Basic " + base64);

		HttpURLConnection httpConn = (HttpURLConnection) urlConn;
		httpConn.setRequestProperty("Authorization", "Basic " + base64);

		httpConn.connect();

		returnValue = httpConn.getInputStream();

		return returnValue;
	}

	public static <OutT extends Object> OutT Post(String url, String userName, String password, Object payload, Class<OutT> outputClass)
			throws Throwable {
		return RestHelper.<OutT> PerformRequest(url, userName, password,
				payload, HttpMethod.POST, true, outputClass);
	}

	public static <OutT extends Object> OutT Get(String url, String userName, String password, Class<OutT> outputClass)
			throws Throwable {
		return RestHelper.<OutT> PerformRequest(url, userName, password, null,
				HttpMethod.GET, true, outputClass);
	}

	public static <OutT extends Object> OutT Put( String url, String userName, String password, Object payload, Class<OutT> outputClass)
			throws Throwable {
		return PerformRequest(url, userName, password, payload, HttpMethod.PUT,
				true, outputClass);
	}

	public static <OutT extends Object, InT extends Object> OutT Delete( String url, String userName, String password, Class<InT> payload, Class<OutT> outputClass)
			throws Throwable {
		return PerformRequest(url, userName, password, payload,
				HttpMethod.DELETE, true, outputClass);
	}

	public static InputStream getStream(String url, String userName,
			String password) throws IOException {
		return PerformStreamRequest(url, userName, password);
	}
}