我正在尝试将我的平板电脑连接到我的 WAMP 服务器中的 Web 服务。我试过做我读过的所有东西，但没有运气连接它。Web 服务从 SQL Server 读取数据并将其显示在应用程序中。目前，这就是它需要做的所有事情。我有一个从教程中遵循的代码，以便我可以执行异步任务，但它仍然没有帮助。这是代码：
package com.example.secondtestsqlserver;
import java.util.ArrayList;
import java.util.List;
import org.apache.http.NameValuePair;
import org.apache.http.message.BasicNameValuePair;
import org.json.JSONArray;
import org.json.JSONException;
import org.json.JSONObject;
import android.app.Activity;
import android.app.ProgressDialog;
import android.os.AsyncTask;
import android.os.Bundle;
import android.os.StrictMode;
import android.util.Log;
import android.view.Menu;
import android.view.View;
import android.widget.EditText;
public class MainActivity extends Activity {
private ProgressDialog pDialog;
JSONParser jsonParser = new JSONParser();
String pid;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
StrictMode.setThreadPolicy(new StrictMode.ThreadPolicy.Builder()
.detectAll()
.penaltyLog()
.penaltyDialog()
.build());
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.activity_main, menu);
return true;
}
public void clickSend(View view) {
new TestWS().execute();
}
class TestWS extends AsyncTask<String, String, String> {
@Override
protected void onPreExecute() {
super.onPreExecute();
pDialog = new ProgressDialog(MainActivity.this);
pDialog.setMessage("Loading product details. Please wait...");
pDialog.setIndeterminate(false);
pDialog.setCancelable(true);
pDialog.show();
}
protected String doInBackground(String... params) {
// updating UI from Background Thread
runOnUiThread(new Runnable() {
public void run() {
// Check for success tag
int success;
try {
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("pid", pid));
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jsonParser.makeHttpRequest(
"http://170.54.162.239:80/webservice.php", "GET", params);
// check your log for json response
Log.d("Single Record Details", json.toString());
// json success tag
success = json.getInt("success");
if (success == 1) {
// successfully received product details
JSONArray productObj = json.getJSONArray("master"); // JSON Array
// get first product object from JSON Array
JSONObject product = productObj.getJSONObject(0);
// product with this pid found
// Edit Text
EditText txtName = (EditText) findViewById(R.id.txtName);
EditText txtPrice = (EditText) findViewById(R.id.txtTest);
// display product data in EditText
txtName.setText(product.getString("test"));
txtPrice.setText(product.getString("name"));
// Log.e("Checking", product.getString("test"));
// Log.e("Checking", product.getString("name"));
}
} catch (JSONException e) {
e.printStackTrace();
}
}
});
return null;
}
protected void onPostExecute(String file_url) {
// dismiss the dialog once got all details
pDialog.dismiss();
}
}
}
这是 JSONParser 类
package com.example.secondtestsqlserver;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.UnsupportedEncodingException;
import java.util.List;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
import org.apache.http.client.entity.UrlEncodedFormEntity;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.utils.URLEncodedUtils;
import org.apache.http.impl.client.DefaultHttpClient;
import org.json.JSONException;
import org.json.JSONObject;
import android.util.Log;
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
// constructor
public JSONParser() {
}
// function get json from url
// by making HTTP POST or GET method
public JSONObject makeHttpRequest(String url, String method,
List<NameValuePair> params) {
// Making HTTP request
try {
// check for request method
if(method == "POST"){
// request method is POST
// defaultHttpClient
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url);
httpPost.setEntity(new UrlEncodedFormEntity(params));
HttpResponse httpResponse = httpClient.execute(httpPost);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}else if(method == "GET"){
// request method is GET
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url += "?" + paramString;
HttpGet httpGet = new HttpGet(url);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
}
} catch (UnsupportedEncodingException e) {
Log.e("Unsupported Encoding", Log.getStackTraceString(e));
} catch (ClientProtocolException e) {
Log.e("Client Protocol", Log.getStackTraceString(e));
} catch (IOException e) {
Log.e("IO Exception", Log.getStackTraceString(e));
}
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());
System.out.println(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());
Log.e("JSON Parser", json);
}
// return JSON String
return jObj;
}
}
这就是 PHP Web 服务
<?php
$serverName = "localhost\SQLExpress";
$connectionOptions = array("Database"=>"Android");
$conn = sqlsrv_connect($serverName, $connectionOptions);
/* if ($conn)
{
echo "Connection established.<br />";
}
else
{
echo "Connection could not be established.<br />";
die(print_r(sqlsrv_errors(), true));
}*/
$query = "SELECT * FROM AndroidTest;";
$result = sqlsrv_query($conn, $query, array(), array("Scrollable" => SQLSRV_CURSOR_KEYSET));
$master = array();
if (sqlsrv_num_rows($result)) {
$master["record"] = array();
while ($posts = sqlsrv_fetch_array($result, SQLSRV_FETCH_ASSOC)) {
$record = array();
$record["test"] = $posts["test"];
$record["name"] = $posts["name"];
array_push($master["record"], $record);
}
$master["success"] = 1;
}
else {
$master["success"] = 0;
$master["message"] = "No products found";
}
header('Content-trype: application/json');
echo json_encode($master);
sqlsrv_close($conn);
?>
我确实知道 PHP 是正确的，因为它为我提供了我想要的数据，但是该应用程序在我的平板电脑中不起作用，在模拟器中也不起作用。另外，请注意，在 MainActivity 类中，我使用了 StrictMode.setThreadPolicy()。这是因为我读到当我得到 onNetworkMainThreadException 时，即使它不安全，这通常也能解决问题。当然，在我找出无法连接的原因之后，我打算更改它。错误是这个：
12-21 09:03:45.049: E/IO Exception(25431): org.apache.http.conn.HttpHostConnectException: Connection to http://170.54.162.239:80 refused
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:183)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.conn.AbstractPoolEntry.open(AbstractPoolEntry.java:164)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.conn.AbstractPooledConnAdapter.open(AbstractPooledConnAdapter.java:119)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.client.DefaultRequestDirector.execute(DefaultRequestDirector.java:360)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:555)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:487)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.client.AbstractHttpClient.execute(AbstractHttpClient.java:465)
12-21 09:03:45.049: E/IO Exception(25431): at com.example.secondtestsqlserver.JSONParser.makeHttpRequest(JSONParser.java:62)
12-21 09:03:45.049: E/IO Exception(25431): at com.example.secondtestsqlserver.MainActivity$TestWS$1.run(MainActivity.java:75)
12-21 09:03:45.049: E/IO Exception(25431): at android.os.Handler.handleCallback(Handler.java:615)
12-21 09:03:45.049: E/IO Exception(25431): at android.os.Handler.dispatchMessage(Handler.java:92)
12-21 09:03:45.049: E/IO Exception(25431): at android.os.Looper.loop(Looper.java:137)
12-21 09:03:45.049: E/IO Exception(25431): at android.app.ActivityThread.main(ActivityThread.java:4745)
12-21 09:03:45.049: E/IO Exception(25431): at java.lang.reflect.Method.invokeNative(Native Method)
12-21 09:03:45.049: E/IO Exception(25431): at java.lang.reflect.Method.invoke(Method.java:511)
12-21 09:03:45.049: E/IO Exception(25431): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-21 09:03:45.049: E/IO Exception(25431): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-21 09:03:45.049: E/IO Exception(25431): at dalvik.system.NativeStart.main(Native Method)
12-21 09:03:45.049: E/IO Exception(25431): Caused by: java.net.ConnectException: failed to connect to /170.54.162.239 (port 80): connect failed: ENETUNREACH (Network is unreachable)
12-21 09:03:45.049: E/IO Exception(25431): at libcore.io.IoBridge.connect(IoBridge.java:114)
12-21 09:03:45.049: E/IO Exception(25431): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:192)
12-21 09:03:45.049: E/IO Exception(25431): at java.net.PlainSocketImpl.connect(PlainSocketImpl.java:459)
12-21 09:03:45.049: E/IO Exception(25431): at java.net.Socket.connect(Socket.java:842)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.conn.scheme.PlainSocketFactory.connectSocket(PlainSocketFactory.java:119)
12-21 09:03:45.049: E/IO Exception(25431): at org.apache.http.impl.conn.DefaultClientConnectionOperator.openConnection(DefaultClientConnectionOperator.java:144)
12-21 09:03:45.049: E/IO Exception(25431): ... 17 more
12-21 09:03:45.049: E/IO Exception(25431): Caused by: libcore.io.ErrnoException: connect failed: ENETUNREACH (Network is unreachable)
12-21 09:03:45.049: E/IO Exception(25431): at libcore.io.Posix.connect(Native Method)
12-21 09:03:45.049: E/IO Exception(25431): at libcore.io.BlockGuardOs.connect(BlockGuardOs.java:85)
12-21 09:03:45.049: E/IO Exception(25431): at libcore.io.IoBridge.connectErrno(IoBridge.java:127)
12-21 09:03:45.049: E/IO Exception(25431): at libcore.io.IoBridge.connect(IoBridge.java:112)
12-21 09:03:45.049: E/IO Exception(25431): ... 22 more
12-21 09:03:45.049: E/Buffer Error(25431): Error converting result java.lang.NullPointerException
12-21 09:03:45.049: E/JSON Parser(25431): Error parsing data org.json.JSONException: End of input at character 0 of
12-21 09:03:45.049: E/AndroidRuntime(25431): FATAL EXCEPTION: main
12-21 09:03:45.049: E/AndroidRuntime(25431): java.lang.NullPointerException
12-21 09:03:45.049: E/AndroidRuntime(25431): at com.example.secondtestsqlserver.MainActivity$TestWS$1.run(MainActivity.java:79)
12-21 09:03:45.049: E/AndroidRuntime(25431): at android.os.Handler.handleCallback(Handler.java:615)
12-21 09:03:45.049: E/AndroidRuntime(25431): at android.os.Handler.dispatchMessage(Handler.java:92)
12-21 09:03:45.049: E/AndroidRuntime(25431): at android.os.Looper.loop(Looper.java:137)
12-21 09:03:45.049: E/AndroidRuntime(25431): at android.app.ActivityThread.main(ActivityThread.java:4745)
12-21 09:03:45.049: E/AndroidRuntime(25431): at java.lang.reflect.Method.invokeNative(Native Method)
12-21 09:03:45.049: E/AndroidRuntime(25431): at java.lang.reflect.Method.invoke(Method.java:511)
12-21 09:03:45.049: E/AndroidRuntime(25431): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:786)
12-21 09:03:45.049: E/AndroidRuntime(25431): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:553)
12-21 09:03:45.049: E/AndroidRuntime(25431): at dalvik.system.NativeStart.main(Native Method)
我不会问我是否还没有尝试过我在这里找到的所有东西以及我在互联网上找到的所有东西。我需要尽快完成这项工作，所以请您给我任何帮助，我们将不胜感激。