我正在尝试使用 netbeans 将客户端(android 应用程序)连接到服务器(PHP)。为此，我在 htdocs 文件夹中编写了一个名为“getAllPeopleBornAfter.php”的 PHP 代码，该代码运行正常。
<?php
mysql_connect("localhost","root","");
mysql_select_db("test");
$q=mysql_query("SELECT * FROM android WHERE ID>'".$_REQUEST['id']."'");
while($e=mysql_fetch_assoc($q))
$output[]=$e;
print(json_encode($output));
mysql_close();
?>
我通过 netbeans 创建了一个新的 javaApplications 并在其中编写了以下代码。
package javaapplication4;
public class JavaApplication4 {
public static void main(String[] args) {
String result = "";
//the year data to send
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
nameValuePairs.add(new BasicNameValuePair("id","1"));
try{
HttpClient httpclient = new DefaultHttpClient();
HttpPost httppost = new HttpPost("localhost/getAllPeopleBornAfter.php");
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
HttpResponse response = httpclient.execute(httppost);
HttpEntity entity = response.getEntity();
InputStream is = entity.getContent();
}catch(Exception e){
Log.e("log_tag", "Error in http connection "+e.toString());
}
//convert response to string
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();
result=sb.toString();
}catch(Exception e){
Log.e("log_tag", "Error converting result "+e.toString());
}
//parse json data
try{
JSONArray jArray = new JSONArray(result);
for(int i=0;i<jArray.length();i++){
JSONObject json_data = jArray.getJSONObject(i);
Log.i("log_tag","id: "+json_data.getInt("ID")+
", description: "+json_data.getString("Description")
);
}
}
catch(JSONException e){
Log.e("log_tag", "Error parsing data "+e.toString());
}
}
}
但是，它给了我一个错误
ant -f C:\\xampp\\htdocs\\JavaApplication4 -Dnb.internal.action.name=run run
init:
deps-jar:
Created dir: C:\xampp\htdocs\JavaApplication4\build
Updating property file: C:\xampp\htdocs\JavaApplication4\build\built-jar.properties
Created dir: C:\xampp\htdocs\JavaApplication4\build\classes
Created dir: C:\xampp\htdocs\JavaApplication4\build\empty
Created dir: C:\xampp\htdocs\JavaApplication4\build\generated-sources\ap-source-output
Compiling 1 source file to C:\xampp\htdocs\JavaApplication4\build\classes
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:10: error: cannot find symbol
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
symbol: class ArrayList
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:10: error: cannot find symbol
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
symbol: class NameValuePair
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:10: error: cannot find symbol
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
symbol: class ArrayList
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:10: error: cannot find symbol
ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>();
symbol: class NameValuePair
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:11: error: cannot find symbol
nameValuePairs.add(new BasicNameValuePair("id","1"));
symbol: class BasicNameValuePair
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:14: error: cannot find symbol
HttpClient httpclient = new DefaultHttpClient();
symbol: class HttpClient
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:14: error: cannot find symbol
HttpClient httpclient = new DefaultHttpClient();
symbol: class DefaultHttpClient
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:15: error: cannot find symbol
HttpPost httppost = new HttpPost("localhost/getAllPeopleBornAfter.php");
symbol: class HttpPost
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:15: error: cannot find symbol
HttpPost httppost = new HttpPost("localhost/getAllPeopleBornAfter.php");
symbol: class HttpPost
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:16: error: cannot find symbol
httppost.setEntity(new UrlEncodedFormEntity(nameValuePairs));
symbol: class UrlEncodedFormEntity
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:17: error: cannot find symbol
HttpResponse response = httpclient.execute(httppost);
symbol: class HttpResponse
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:18: error: cannot find symbol
HttpEntity entity = response.getEntity();
symbol: class HttpEntity
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:19: error: cannot find symbol
InputStream is = entity.getContent();
symbol: class InputStream
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:21: error: cannot find symbol
Log.e("log_tag", "Error in http connection "+e.toString());
symbol: variable Log
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:25: error: cannot find symbol
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
symbol: class BufferedReader
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:25: error: cannot find symbol
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
symbol: class BufferedReader
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:25: error: cannot find symbol
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
symbol: class InputStreamReader
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:25: error: cannot find symbol
BufferedReader reader = new BufferedReader(new InputStreamReader(is,"iso-8859-1"),8);
symbol: variable is
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:31: error: cannot find symbol
is.close();
symbol: variable is
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:35: error: cannot find symbol
Log.e("log_tag", "Error converting result "+e.toString());
symbol: variable Log
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:40: error: cannot find symbol
JSONArray jArray = new JSONArray(result);
symbol: class JSONArray
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:40: error: cannot find symbol
JSONArray jArray = new JSONArray(result);
symbol: class JSONArray
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:42: error: cannot find symbol
JSONObject json_data = jArray.getJSONObject(i);
symbol: class JSONObject
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:43: error: cannot find symbol
Log.i("log_tag","id: "+json_data.getInt("ID")+
symbol: variable Log
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:48: error: cannot find symbol
catch(JSONException e){
symbol: class JSONException
location: class JavaApplication4
C:\xampp\htdocs\JavaApplication4\src\javaapplication4\JavaApplication4.java:49: error: cannot find symbol
Log.e("log_tag", "Error parsing data "+e.toString());
symbol: variable Log
location: class JavaApplication4
26 errors
C:\xampp\htdocs\JavaApplication4\nbproject\build-impl.xml:923: The following error occurred while executing this line:
C:\xampp\htdocs\JavaApplication4\nbproject\build-impl.xml:263: Compile failed; see the compiler error output for details.
BUILD FAILED (total time: 0 seconds)
由于我是java初学者，请有人指导我。 谢谢。
最佳答案
更新
请查看this回答。
原始答案:
请检查如何实例化变量等。
在您的代码中ArrayList<NameValuePair> nameValuePairs = new ArrayList<NameValuePair>(); ,
你从哪里得到<NameValuePair> ？它应该像这样实例化:
ArrayList<String> TheNameOfYourList = new ArrayList<String>();
阅读并查看您的日志。这非常简单。
关于java - 在 Netbeans 中连接到服务器端 (PHP) 期间客户端 (Android) 出现错误，我们在Stack Overflow上找到一个类似的问题： https://stackoverflow.com/questions/34848330/