我正在尝试在 Android 中加载方法的参数，并通过 http 将请求通过我拥有的服务器在线发送到 php 文件，其中它进行 SQL 查询并根据 Android http 请求发送的参数提取相关元素.
我使用该参数发送/发出 HTTP 请求的函数
jsonFUNC
// Creating JSON Parser instance
JSONparser jParser = new JSONparser();
// getting JSON string from URL
//JSONObject json = jParser.getJSONFromUrl(url_product_details);
// Building Parameters
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("user_id", user_id));
// getting product details by making HTTP request
// Note that product details url will use GET request
JSONObject json = jParser.makeHttpRequest(
url_product_details, "GET", params);
// check your log for json response
Log.d("Details", json.toString());
我的完整 JSONparser 类承载了 makeHttpRequest() 函数，它工作得非常好我可以说至少对于函数 getJSONFromUrl：
package library;
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) {
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;
}
public JSONObject getJSONFromUrl(String url, List<NameValuePair> params) {
// Making HTTP request
try {
// 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();
} 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();
Log.e("JSON", json);
} 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;
}
}
我在服务器上的 PHP 代码文件：
<?php
// array for JSON response
$response = array();
// include db connect class
require_once '/DB_Connect.php';
// connecting to db
$db = new DB_CONNECT();
// check for post data
if (isset($_GET["user_id"])) {
$user_id = $_GET['user_id'];
// get a product from products table
$result = mysql_query("SELECT HTTP FROM INFO WHERE user_id = $user_id");
if (!empty($result)) {
// check for empty result
if (mysql_num_rows($result) > 0) {
$result = mysql_fetch_array($result);
$user_info = array();
$user_info["HTTP"] = $result["HTTP"];
// success
$response["success"] = 1;
// user node
$response["user_info"] = array();
array_push($response["user_info"], $user_info);
// echoing JSON response
echo json_encode($response);
} else {
// no product found
$response["success"] = 0;
$response["message"] = "No product found";
// echo no users JSON
echo json_encode($response);
}
} else {
// no product found
$response["success"] = 0;
$response["message"] = "No product found";
// echo no users JSON
echo json_encode($response);
}
} else {
// required field is missing
$response["success"] = 0;
$response["message"] = "Required field(s) is missing";
// echoing JSON response
echo json_encode($response);
}
?>
我收到的错误：
08-23 17:20:01.780: E/JSON Parser(23489): Error parsing data org.json.JSONException: End of input at character 0 of
（是的，我没有得到完整的错误，直到字符 0） *然后 VM 关闭，我收到以下错误：*
08-23 17:20:01.780: E/AndroidRuntime(23489): FATAL EXCEPTION: main
08-23 17:20:01.780: E/AndroidRuntime(23489): java.lang.NullPointerException
08-23 17:20:01.780: E/AndroidRuntime(23489): at com.database_demo.DashboardActivity.jsonFUNC(DashboardActivity.java:237)
08-23 17:20:01.780: E/AndroidRuntime(23489): at com.database_demo.DashboardActivity$2.onClick(DashboardActivity.java:111)
08-23 17:20:01.780: E/AndroidRuntime(23489): at android.view.View.performClick(View.java:4223)
08-23 17:20:01.780: E/AndroidRuntime(23489): at android.view.View$PerformClick.run(View.java:17275)
08-23 17:20:01.780: E/AndroidRuntime(23489): at android.os.Handler.handleCallback(Handler.java:615)
08-23 17:20:01.780: E/AndroidRuntime(23489): at android.os.Handler.dispatchMessage(Handler.java:92)
08-23 17:20:01.780: E/AndroidRuntime(23489): at android.os.Looper.loop(Looper.java:137)
08-23 17:20:01.780: E/AndroidRuntime(23489): at android.app.ActivityThread.main(ActivityThread.java:4898)
08-23 17:20:01.780: E/AndroidRuntime(23489): at java.lang.reflect.Method.invokeNative(Native Method)
08-23 17:20:01.780: E/AndroidRuntime(23489): at java.lang.reflect.Method.invoke(Method.java:511)
08-23 17:20:01.780: E/AndroidRuntime(23489): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
08-23 17:20:01.780: E/AndroidRuntime(23489): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
08-23 17:20:01.780: E/AndroidRuntime(23489): at dalvik.system.NativeStart.main(Native Method)
强调文本
使用 POST 的更新问题：
08-24 19:43:23.685: E/JSON Parser(6982): Error parsing data org.json.JSONException: End of input at character 0 of
08-24 19:43:23.685: W/System.err(6982): org.json.JSONException: No value for information
08-24 19:43:23.685: W/System.err(6982): at org.json.JSONObject.get(JSONObject.java:354)
08-24 19:43:23.685: W/System.err(6982): at org.json.JSONObject.getJSONArray(JSONObject.java:544)
08-24 19:43:23.690: W/System.err(6982): at com.database_demo.DashboardActivity.jsonFUNC(DashboardActivity.java:233)
08-24 19:43:23.690: W/System.err(6982): at com.database_demo.DashboardActivity$2.onClick(DashboardActivity.java:111)
08-24 19:43:23.690: W/System.err(6982): at android.view.View.performClick(View.java:4223)
08-24 19:43:23.695: W/System.err(6982): at android.view.View$PerformClick.run(View.java:17275)
08-24 19:43:23.695: W/System.err(6982): at android.os.Handler.handleCallback(Handler.java:615)
08-24 19:43:23.695: W/System.err(6982): at android.os.Handler.dispatchMessage(Handler.java:92)
08-24 19:43:23.695: W/System.err(6982): at android.os.Looper.loop(Looper.java:137)
08-24 19:43:23.695: W/System.err(6982): at android.app.ActivityThread.main(ActivityThread.java:4898)
08-24 19:43:23.695: W/System.err(6982): at java.lang.reflect.Method.invokeNative(Native Method)
08-24 19:43:23.695: W/System.err(6982): at java.lang.reflect.Method.invoke(Method.java:511)
08-24 19:43:23.695: W/System.err(6982): at com.android.internal.os.ZygoteInit$MethodAndArgsCaller.run(ZygoteInit.java:1008)
08-24 19:43:23.700: W/System.err(6982): at com.android.internal.os.ZygoteInit.main(ZygoteInit.java:775)
08-24 19:43:23.700: W/System.err(6982): at dalvik.system.NativeStart.main(Native Method)