我尝试了所有可能的方法，但仍然遇到以下错误-
1.无法解析符号ClientProtocolException
2.无法解析符号HttpPost
3.无法解析符号DefaultHttpClient
JSONParser.java
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
public JSONObject getJSONFromUrl(String urlString) throws JSONException {
// Making HTTP request
try{
// defaultHttpClient
HttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
BufferedReader reader = new BufferedReader(new InputStreamReader(
is, "iso-8859-1"), 8);
StringBuilder sb = new StringBuilder();
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "n");
}
is.close();
json = sb.toString();
} catch (Exception e) {
Log.e("Buffer Error", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
MainActivity.java
public class contactsmap extends Fragment {
private static String url = "A URL";
private static final String TAG_USER = "user";
private static final String TAG_ID = "id";
private static final String TAG_NAME = "name";
private static final String TAG_EMAIL = "email";
JSONArray user = null;
public View onCreateView(LayoutInflater inflater, @Nullable ViewGroup container, @Nullable Bundle savedInstanceState) {
View v = inflater.inflate(R.layout.contactsmap, container, false);
JSONParser jParser = new JSONParser();
JSONObject json = null;
// Getting JSON from URL
try {
json = jParser.getJSONFromUrl(url);
}
catch (JSONException e) {
e.printStackTrace();
}
try {
// Getting JSON Array
user = json.getJSONArray(TAG_USER);
JSONObject c = user.getJSONObject(0);
// Storing JSON item in a Variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
//Importing TextView
final TextView uid = (TextView)v.findViewById(R.id.textView1);
//Set JSON Data in TextView
uid.setText(id);
} catch (JSONException e) {
e.printStackTrace();
}
return v;
}
}
build.gradle
apply plugin: 'com.android.application'
android {
compileSdkVersion 23
buildToolsVersion "23.0.0"
useLibrary 'org.apache.http.legacy'
defaultConfig {
applicationId "com.example.niki"
minSdkVersion 8
targetSdkVersion 23
versionCode 1
versionName "1.0"
}
buildTypes {
release {
minifyEnabled false
proguardFiles getDefaultProguardFile('proguard-android.txt'), 'proguard-rules.pro'
}
}
}
dependencies {
compile fileTree(dir: 'libs', include: ['*.jar'])
compile 'com.android.support:appcompat-v7:23.1.1'
compile 'com.android.support:design:22.2.0'
compile 'com.android.support:recyclerview-v7:22.2.1'
compile 'com.android.support:support-v4:23.0.0'
compile 'com.google.android.gms:play-services:+'
compile 'org.apache.httpcomponents:httpclient:4.2.6'
compile 'org.apache.httpcomponents:httpmime:4.2.6'
compile files('libs/core.jar')
}
表现
<?xml version="1.0" encoding="utf-8"?>
<manifest xmlns:android="http://schemas.android.com/apk/res/android"
package="com.example.niki" >
<uses-permission android:name="android.permission.READ_CONTACTS" >
</uses-permission>
<uses-permission android:name="android.permission.INTERNET"/>
<uses-permission android:name="android.permission.WRITE_EXTERNAL_STORAGE" />
<uses-permission android:name="android.permission.INTERNET"/>
<application
android:allowBackup="true"
android:icon="@mipmap/ic_launcher"
android:label="@string/app_name"
android:theme="@style/AppTheme" >
<activity
android:name=".Swipe"
android:label="@string/app_name" >
<intent-filter>
<action android:name="android.intent.action.MAIN" />
<category android:name="android.intent.category.LAUNCHER" />
</intent-filter>
</activity>
</application>
最佳答案
不推荐使用HttpClient。我为网络操作（包括POST）创建了一个类。尝试这个 ：
只需从onCreate运行new AsyncTask_GrabSource().execute();；
我在我的项目中使用NetworkOps util。尝试一下：
import android.content.Context;
import android.net.Uri;
import android.util.Log;
import com.csehelper.variables.Constants;
import com.csehelper.variables.Keys;
import com.csehelper.variables.Url;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.ProtocolException;
import java.net.SocketTimeoutException;
import java.net.URL;
import java.util.ArrayList;
public class NetworkOps {
public final String EXCEPTION = "~Exception~";
/****************************
* Method to Grab Source
****************************/
public static String GrabSource(String URL) {
return PostData(URL, null);
}
/**
* *****************************************
* Method to Grab Source code from URL
* Posting Data
* *****************************************
*/
private static String PostData(String url, Uri.Builder uribuilder) {
String Source;
HttpURLConnection.setFollowRedirects(false);
HttpURLConnection urlConnection = null;
try {
urlConnection = (HttpURLConnection) new URL(url).openConnection();
urlConnection.setDoOutput(true);
urlConnection.setConnectTimeout(10000);
if(uribuilder != null) {
String query = uribuilder.build().getEncodedQuery();
OutputStream os = urlConnection.getOutputStream();
BufferedWriter writer = new BufferedWriter(
new OutputStreamWriter(os, "UTF-8"));
writer.write(query);
writer.flush();
writer.close();
os.close();
}
urlConnection.connect();
if (urlConnection.getResponseCode() == HttpURLConnection.HTTP_OK) {
String line;
StringBuilder builder = new StringBuilder();
InputStreamReader isr = new InputStreamReader(
urlConnection.getInputStream());
BufferedReader reader = new BufferedReader(isr);
while ((line = reader.readLine()) != null) {
builder.append(line);
}
Source = builder.toString();
} else {
Source = EXCEPTION + "Server unreachable. Check network connection.";
}
} catch (SocketTimeoutException e) {
Source = EXCEPTION + "Connection timed out.";
} catch (java.net.UnknownHostException e) {
Source = EXCEPTION + Constants.EXCEPTION_NO_NET;
} catch (ArrayIndexOutOfBoundsException e) {
Source = EXCEPTION + "Server error";
} catch (ProtocolException e) {
Source = EXCEPTION + "Protocol error";
} catch (IOException e) {
Source = EXCEPTION + "Server unreachable. Check network connection.";
} catch (Exception e) {
Source = EXCEPTION + "Error:" + e.toString() + " - "
+ e.getMessage();
e.printStackTrace();
} finally {
if (urlConnection != null) urlConnection.disconnect();
}
return Source;
}
}
从AsyncTask调用这些静态函数：
/*********************************
* AsyncTask to GrabSource
********************************/
class AsyncTask_GrabSource extends AsyncTask<Void, Void, Void> {
String Source = null;
String url = "https://enigmatic-woodland-35608.herokuapp.com/pager.json";
@Override
protected void onPreExecute() {
//Runs on Main Thread. You can access your UI elements here.
}
@Override
protected Void doInBackground(Void... params) {
// Don't access any UI elements from this function
Source = NetworkOps.GrabSource(this.url);
return null;
}
@Override
protected void onPostExecute(Void result) {
if (Source != null) {
if (!Source.contains(EXCEPTION)) {
//Show Error Message or do whatever you want
} else {
//Do Whatever with your Grabbed Sourcecode.
// This function runs on UI Thread, so you can update UI elements here
//Add your code here :
try {
json = jParser.getJSONFromUrl(url);
}
catch (JSONException e) {
e.printStackTrace();
}
try {
// Getting JSON Array
user = json.getJSONArray(TAG_USER);
JSONObject c = user.getJSONObject(0);
// Storing JSON item in a Variable
String id = c.getString(TAG_ID);
String name = c.getString(TAG_NAME);
String email = c.getString(TAG_EMAIL);
//Importing TextView
final TextView uid = (TextView)v.findViewById(R.id.textView1);
//Set JSON Data in TextView
uid.setText(id);
} catch (JSONException e) {
e.printStackTrace();
}
}
}
}
您也可以使用函数PostData发布数据。在方法doInBackground中，添加以下内容：
Uri.Builder builder = new Uri.Builder()
.appendQueryParameter("key", "value")
.appendQueryParameter("key2", "value2");
Source = NetworkOps.PostData(getApplicationContext(), url, builder);