我正试图弄清楚如何使用HTTPClient从Android发布JSON。我一直试图解决这个问题,我已经在网上找到了很多例子,但我无法让它们中的任何一个工作。我相信这是因为我缺乏一般的JSON /网络知识。我知道那里有很多例子,但有人可以指点我一个实际的教程吗?我正在寻找一步一步的过程,包括代码和解释为什么你要做每一步,或者说那个步骤做了什么。它不需要复杂,简单就足够了。
同样,我知道有很多例子,我只是在寻找一个例子,解释究竟发生了什么以及为什么这样做。
如果有人知道有关这方面的好Android手册,那么请告诉我。
再次感谢帮助@terrance,这是我在下面描述的代码
public void shNameVerParams() throws Exception{
String path = //removed
HashMap params = new HashMap();
params.put(new String("Name"), "Value");
params.put(new String("Name"), "Value");
try {
HttpClient.SendHttpPost(path, params);
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
}
答案 0 :(得分:157)
在这个答案中,我使用的是example posted by Justin Grammens。
JSON代表JavaScript Object Notation。在JavaScript中,属性可以像object1.name
一样引用,也可以像object['name'];
一样引用。本文中的示例使用了这一点JSON。
零件
粉丝对象,电子邮件为密钥,foo @ bar.com为值
{
fan:
{
email : 'foo@bar.com'
}
}
因此等效对象为fan.email;
或fan['email'];
。两者都具有相同的值
'foo@bar.com'
。
以下是我们的作者用来制作HttpClient Request的内容。我并不认为自己是这方面的专家,所以如果有人有更好的方式来解释某些术语,那就免费了。
public static HttpResponse makeRequest(String path, Map params) throws Exception
{
//instantiates httpclient to make request
DefaultHttpClient httpclient = new DefaultHttpClient();
//url with the post data
HttpPost httpost = new HttpPost(path);
//convert parameters into JSON object
JSONObject holder = getJsonObjectFromMap(params);
//passes the results to a string builder/entity
StringEntity se = new StringEntity(holder.toString());
//sets the post request as the resulting string
httpost.setEntity(se);
//sets a request header so the page receving the request
//will know what to do with it
httpost.setHeader("Accept", "application/json");
httpost.setHeader("Content-type", "application/json");
//Handles what is returned from the page
ResponseHandler responseHandler = new BasicResponseHandler();
return httpclient.execute(httpost, responseHandler);
}
如果您不熟悉Map
数据结构,请查看Java Map reference。简而言之,地图类似于字典或散列。
private static JSONObject getJsonObjectFromMap(Map params) throws JSONException {
//all the passed parameters from the post request
//iterator used to loop through all the parameters
//passed in the post request
Iterator iter = params.entrySet().iterator();
//Stores JSON
JSONObject holder = new JSONObject();
//using the earlier example your first entry would get email
//and the inner while would get the value which would be 'foo@bar.com'
//{ fan: { email : 'foo@bar.com' } }
//While there is another entry
while (iter.hasNext())
{
//gets an entry in the params
Map.Entry pairs = (Map.Entry)iter.next();
//creates a key for Map
String key = (String)pairs.getKey();
//Create a new map
Map m = (Map)pairs.getValue();
//object for storing Json
JSONObject data = new JSONObject();
//gets the value
Iterator iter2 = m.entrySet().iterator();
while (iter2.hasNext())
{
Map.Entry pairs2 = (Map.Entry)iter2.next();
data.put((String)pairs2.getKey(), (String)pairs2.getValue());
}
//puts email and 'foo@bar.com' together in map
holder.put(key, data);
}
return holder;
}
的
的请随时评论关于这篇文章的任何问题,或者如果我没有做出明确的事情,或者我没有触及你仍然感到困惑的事情......等等。
(如果Justin Grammens不同意,我会退出。但如果没有,那么感谢Justin对此感到很冷静。)
我刚刚发表了关于如何使用代码的评论,并意识到返回类型中存在错误。 方法签名设置为返回一个字符串,但在这种情况下它没有返回任何东西。我改变了签名 到HttpResponse并会在Getting Response Body of HttpResponse上引用您的链接 路径变量是url,我更新以修复代码中的错误。
答案 1 :(得分:41)
这是@Ttrance答案的另一种解决方案。您可以轻松地外包转换。 Gson library可以很好地将各种数据结构转换为JSON,反之亦然。
public static void execute() {
Map<String, String> comment = new HashMap<String, String>();
comment.put("subject", "Using the GSON library");
comment.put("message", "Using libraries is convenient.");
String json = new GsonBuilder().create().toJson(comment, Map.class);
makeRequest("http://192.168.0.1:3000/post/77/comments", json);
}
public static HttpResponse makeRequest(String uri, String json) {
try {
HttpPost httpPost = new HttpPost(uri);
httpPost.setEntity(new StringEntity(json));
httpPost.setHeader("Accept", "application/json");
httpPost.setHeader("Content-type", "application/json");
return new DefaultHttpClient().execute(httpPost);
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
return null;
}
使用Jackson代替Gson可以完成类似的操作。我还建议您查看Retrofit,它会为您隐藏许多样板代码。对于更有经验的开发人员,我建议您尝试RxAndroid。
答案 2 :(得分:33)
我建议使用此HttpURLConnection
代替HttpGet
。由于HttpGet
已在Android API级别22中弃用。
HttpURLConnection httpcon;
String url = null;
String data = null;
String result = null;
try {
//Connect
httpcon = (HttpURLConnection) ((new URL (url).openConnection()));
httpcon.setDoOutput(true);
httpcon.setRequestProperty("Content-Type", "application/json");
httpcon.setRequestProperty("Accept", "application/json");
httpcon.setRequestMethod("POST");
httpcon.connect();
//Write
OutputStream os = httpcon.getOutputStream();
BufferedWriter writer = new BufferedWriter(new OutputStreamWriter(os, "UTF-8"));
writer.write(data);
writer.close();
os.close();
//Read
BufferedReader br = new BufferedReader(new InputStreamReader(httpcon.getInputStream(),"UTF-8"));
String line = null;
StringBuilder sb = new StringBuilder();
while ((line = br.readLine()) != null) {
sb.append(line);
}
br.close();
result = sb.toString();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
答案 3 :(得分:5)
此任务的代码太多,请检查此库https://github.com/kodart/Httpzoid 在内部使用GSON并提供与对象一起使用的API。所有JSON详细信息都被隐藏。
Http http = HttpFactory.create(context);
http.get("http://example.com/users")
.handler(new ResponseHandler<User[]>() {
@Override
public void success(User[] users, HttpResponse response) {
}
}).execute();
答案 4 :(得分:3)
有几种方法可以建立HHTP连接并从RESTFULL Web服务获取数据。最近的一个是GSON。但在进入GSON之前,您必须了解创建HTTP客户端和与远程服务器进行数据通信的最传统方式。我已经提到了发送POST和amp;的两种方法。使用HTTPClient获取GET请求。
/**
* This method is used to process GET requests to the server.
*
* @param url
* @return String
* @throws IOException
*/
public static String connect(String url) throws IOException {
HttpGet httpget = new HttpGet(url);
HttpResponse response;
HttpParams httpParameters = new BasicHttpParams();
// Set the timeout in milliseconds until a connection is established.
// The default value is zero, that means the timeout is not used.
int timeoutConnection = 60*1000;
HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
// Set the default socket timeout (SO_TIMEOUT)
// in milliseconds which is the timeout for waiting for data.
int timeoutSocket = 60*1000;
HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
HttpClient httpclient = new DefaultHttpClient(httpParameters);
try {
response = httpclient.execute(httpget);
HttpEntity entity = response.getEntity();
if (entity != null) {
InputStream instream = entity.getContent();
result = convertStreamToString(instream);
//instream.close();
}
}
catch (ClientProtocolException e) {
Utilities.showDLog("connect","ClientProtocolException:-"+e);
} catch (IOException e) {
Utilities.showDLog("connect","IOException:-"+e);
}
return result;
}
/**
* This method is used to send POST requests to the server.
*
* @param URL
* @param paramenter
* @return result of server response
*/
static public String postHTPPRequest(String URL, String paramenter) {
HttpParams httpParameters = new BasicHttpParams();
// Set the timeout in milliseconds until a connection is established.
// The default value is zero, that means the timeout is not used.
int timeoutConnection = 60*1000;
HttpConnectionParams.setConnectionTimeout(httpParameters, timeoutConnection);
// Set the default socket timeout (SO_TIMEOUT)
// in milliseconds which is the timeout for waiting for data.
int timeoutSocket = 60*1000;
HttpConnectionParams.setSoTimeout(httpParameters, timeoutSocket);
HttpClient httpclient = new DefaultHttpClient(httpParameters);
HttpPost httppost = new HttpPost(URL);
httppost.setHeader("Content-Type", "application/json");
try {
if (paramenter != null) {
StringEntity tmp = null;
tmp = new StringEntity(paramenter, "UTF-8");
httppost.setEntity(tmp);
}
HttpResponse httpResponse = null;
httpResponse = httpclient.execute(httppost);
HttpEntity entity = httpResponse.getEntity();
if (entity != null) {
InputStream input = null;
input = entity.getContent();
String res = convertStreamToString(input);
return res;
}
}
catch (Exception e) {
System.out.print(e.toString());
}
return null;
}