大家好我在我的机器上设置了本地Web服务,它是一个使用JPA在netbeans中构建的Web服务。我也将它本地连接到mySQL服务器。我有数据库和Web服务连接。 Web服务可以显示XML / JSON。我的问题是让Android模拟器从Web服务中使用JSON。我们使用的URL是“http://10.0.2.2:8080/Web4/resources/hotel2s/”这应该允许模拟器连接到Web服务我是否正确?当我尝试启动并消耗模拟器崩溃时。这是一些源代码。我们确信它应该读入并解析GSON等,但我们不确定它是否连接。
结果类
public class hotel_Result
{
@SerializedName("hotelAddress")
protected String hotelAddress;
@SerializedName("HotelDescription")
protected String hotelDescription;
@SerializedName("hotelName")
protected String hotelName;
@SerializedName("hotelRating")
protected int hotelRating;
}
酒店回复类
public class hotel_Response
{
public List<hotel_Result> hotelresults;
public String query;
}
MAIN CLASS
public class connectRest extends Activity
{
// We tried Reg's machines ip here as well and it crashed also used different ips is this correct for the emulator to connect to it?
String url = "http://10.0.2.2:8080/Web4/resources/hotel2s/";
@Override
public void onCreate(Bundle savedInstanceState)
{
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
InputStream source = retrieveStream(url); // Stream in the URL
Gson gson = new Gson(); // GSON object
Reader reader = new InputStreamReader(source); // Read in the stream
hotel_Response response = gson.fromJson(reader,hotel_Response.class); // Fill in the variables in the class hotel_response
Toast.makeText(this,response.query,Toast.LENGTH_SHORT).show();
List<hotel_Result> hotelresults = response.hotelresults;
for(hotel_Result hotel_Result : hotelresults)
{
Toast.makeText(this,hotel_Result.hotelName,Toast.LENGTH_SHORT).show();
}
}
private InputStream retrieveStream(String url)
{
DefaultHttpClient client = new DefaultHttpClient();
HttpGet getRequest = new HttpGet(url);
try{
HttpResponse getResponse = client.execute(getRequest);
final int statusCode = getResponse.getStatusLine().getStatusCode();
if(statusCode != HttpStatus.SC_OK)
{
Log.w(getClass().getSimpleName(),"Error" + statusCode + " for URL " + url);
return null;
}
HttpEntity getResponseEntity = getResponse.getEntity();
return getResponseEntity.getContent();
}
catch(IOException e)
{
getRequest.abort();
Log.w(getClass().getSimpleName(),"Error for URL " + url, e);
}
return null;
}
}
答案 0 :(得分:1)
确保您的清单中有允许的互联网访问权限。
这是一个更好的try-catch实现,它在AsyncTask()中工作以保持UI线程的快乐:)原始文章可以在Java Code Geeks(http://www.javacodegeeks.com/2011/01/android-json-parsing-gson-tutorial.html)上找到,但它缺乏我的改进!
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import com.google.gson.Gson;
import com.javacodegeeks.android.json.model.Result;
import com.javacodegeeks.android.json.model.SearchResponse;
public class JsonParsingActivity extends Activity {
private static final String url = "http://search.twitter.com/search.json?q=javacodegeeks";
protected InitTask _initTask;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button)findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
_initTask = new InitTask();
_initTask.execute( getApplicationContext() );
}
});
}
@Override
public void onStop() {
super.onStop();
_initTask.cancel(true);
}
protected class InitTask extends AsyncTask<Context, String, SearchResponse>
{
@Override
protected SearchResponse doInBackground( Context... params )
{
InputStream source = retrieveStream(url);
SearchResponse response = null;
if (source != null) {
Gson gson = new Gson();
Reader reader = new InputStreamReader(source);
try {
response = gson.fromJson(reader, SearchResponse.class);
publishProgress( response.query );
reader.close();
} catch (Exception e) {
Log.w(getClass().getSimpleName(), "Error: " + e.getMessage() + " for URL " + url);
}
}
if (!this.isCancelled()) {
return response;
} else {
return null;
}
}
@Override
protected void onProgressUpdate(String... s)
{
super.onProgressUpdate(s);
Toast.makeText(getApplicationContext(), s[0], Toast.LENGTH_SHORT).show();
}
@Override
protected void onPostExecute( SearchResponse response )
{
super.onPostExecute(response);
StringBuilder builder = new StringBuilder();
if (response != null) {
String delim = "* ";
List<Result> results = response.results;
for (Result result : results) {
builder.append(delim).append(result.fromUser);
delim="\n* ";
}
}
if (builder.length() > 0) {
Toast.makeText(getApplicationContext(), builder.toString(), Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getApplicationContext(), "The response was empty.", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onCancelled() {
super.onCancelled();
Toast.makeText(getApplicationContext(), "The operation was cancelled.", 1).show();
}
private InputStream retrieveStream(String url) {
DefaultHttpClient client = new DefaultHttpClient();
HttpGet getRequest;
try {
getRequest = new HttpGet(url);
HttpResponse getResponse = client.execute(getRequest);
HttpEntity getResponseEntity = getResponse.getEntity();
return getResponseEntity.getContent();
} catch (Exception e) {
Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
return null;
}
}
}
}
答案 1 :(得分:0)
这是上面代码的完整try-catch实现。我先实现了这个,然后意识到我真正需要知道的是通过/失败。无论如何,可能会帮助某人。再次,道具转到Java Code Geeks让我开始...... Android JSON Parsing with GSON Tutorial
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.impl.client.DefaultHttpClient;
import android.app.Activity;
import android.content.Context;
import android.os.AsyncTask;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import com.google.gson.Gson;
import com.google.gson.JsonIOException;
import com.google.gson.JsonSyntaxException;
import com.javacodegeeks.android.json.model.Result;
import com.javacodegeeks.android.json.model.SearchResponse;
public class JsonParsingActivity extends Activity {
private static final String url = "http://search.twitter.com/search.json?q=javacodegeeks";
protected InitTask _initTask;
@Override
public void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.main);
Button button = (Button)findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
public void onClick(View v) {
_initTask = new InitTask();
_initTask.execute( getApplicationContext() );
}
});
}
@Override
public void onStop() {
super.onStop();
_initTask.cancel(true);
}
protected class InitTask extends AsyncTask<Context, String, SearchResponse>
{
@Override
protected SearchResponse doInBackground( Context... params )
{
InputStream source = retrieveStream(url);
SearchResponse response = null;
if (source != null) {
Gson gson = new Gson();
Reader reader = new InputStreamReader(source);
try {
response = gson.fromJson(reader, SearchResponse.class);
publishProgress( response.query );
} catch (JsonSyntaxException e) {
Log.w(getClass().getSimpleName(), "Error: " + e.getMessage() + " for URL " + url);
return null;
} catch (JsonIOException e) {
Log.w(getClass().getSimpleName(), "Error: " + e.getMessage() + " for URL " + url);
return null;
} finally {
try {
reader.close();
} catch (IOException e) {
Log.w(getClass().getSimpleName(), "Error: " + e.getMessage() + " for URL " + url);
}
}
}
if (!this.isCancelled()) {
return response;
} else {
return null;
}
}
@Override
protected void onProgressUpdate(String... s)
{
super.onProgressUpdate(s);
Toast.makeText(getApplicationContext(), s[0], Toast.LENGTH_SHORT).show();
}
@Override
protected void onPostExecute( SearchResponse response )
{
super.onPostExecute(response);
StringBuilder builder = new StringBuilder();
if (response != null) {
String delim = "* ";
List<Result> results = response.results;
for (Result result : results) {
builder.append(delim).append(result.fromUser);
delim="\n* ";
}
}
if (builder.length() > 0) {
Toast.makeText(getApplicationContext(), builder.toString(), Toast.LENGTH_SHORT).show();
} else {
Toast.makeText(getApplicationContext(), "The response was empty.", Toast.LENGTH_SHORT).show();
}
}
@Override
protected void onCancelled() {
super.onCancelled();
Toast.makeText(getApplicationContext(), "The operation was cancelled.", 1).show();
}
private InputStream retrieveStream(String url) {
DefaultHttpClient client = new DefaultHttpClient();
HttpGet getRequest;
try {
getRequest = new HttpGet(url);
try {
HttpResponse getResponse = client.execute(getRequest);
final int statusCode = getResponse.getStatusLine().getStatusCode();
if (statusCode != HttpStatus.SC_OK) {
Log.w(getClass().getSimpleName(), "Error " + statusCode + " for URL " + url);
return null;
}
HttpEntity getResponseEntity = getResponse.getEntity();
try {
return getResponseEntity.getContent();
} catch (IllegalStateException e) {
getRequest.abort();
Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
return null;
} catch (IOException e) {
getRequest.abort();
Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
return null;
}
} catch (ClientProtocolException e) {
getRequest.abort();
Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
} catch (IOException e) {
getRequest.abort();
Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
}
} catch (IllegalArgumentException e) {
Log.w(getClass().getSimpleName(), "Error for URL " + url, e);
}
return null;
}
}
}