經歷兩天的琢磨，終于把android連接服務器端php，讀取mysql這一塊弄好了。

先說說這幾天遇到的問題。

http://wenku.baidu.com/view/87ca3bfa700abb68a982fbca.html

這是我參照的資料，原先我一度認為是不能實例化ServiceLink類，后來在其中弄了好多了Log.i后發現不是這樣的。

第一個遇到的問題是

HttpPost httpPost = new HttpPost(url);

?其中url一定要寫http:// 這點很重要，否則就會報錯

03-07 16:16:57.678: E/AndroidRuntime(517): java.lang.IllegalStateException: Target host must not be null, or set in parameters.

其次是要申請權限，在Manifest里申請。

<uses-permission android:name="android.permission.INTERNET"></uses-permission>

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?然后就是php端的了。

第一，不能有BOM頭，這個可以用notepad++ 來編寫無BOM文檔。如果沒有去掉BOM會彈出以下錯誤。

JSONException: java.lang.String cannot be converted to JSONObject

?第二，一定要是純JSON輸出，中文必須用utf-8，否則也會出現上面的錯誤。

貼一下我的JAVA代碼和PHP代碼

//Activity

import org.json.JSONObject;import android.os.Bundle; import android.app.Activity; import android.util.Log; import android.view.Menu; import android.view.View; import android.widget.Button; import android.widget.TextView;public class QRcodeActivity extends Activity {private ServiceLink servicelink = new ServiceLink();private Button loginsubmit;private Button logincancer;private TextView hostname;private TextView username;private TextView password;@Overrideprotected void onCreate(Bundle savedInstanceState) {super.onCreate(savedInstanceState);setContentView(R.layout.activity_qrcode);loginsubmit = (Button)findViewById(R.id.loginsubmit);logincancer = (Button)findViewById(R.id.logincencer);hostname = (TextView)findViewById(R.id.edithostname);username = (TextView)findViewById(R.id.editusername);password = (TextView)findViewById(R.id.editpassword);Log.i("login","Listener!");loginsubmit.setOnClickListener(new View.OnClickListener() {@Overridepublic void onClick(View view) {// TODO Auto-generated method stubLog.i("login","reading JSON!");String hostnamestring = hostname.getText().toString();Log.i("string",hostnamestring);String usernamestring = username.getText().toString();Log.i("string",usernamestring);String passwordstring = password.getText().toString();Log.i("string",passwordstring);Log.i("login","new JSONObject!");JSONObject jsonobject= new JSONObject();Log.i("login","setURL");servicelink.setURL("http://210.38.160.75/QRcode.php");Log.i("login","serviceLogin");jsonobject = servicelink.serviceLogin(hostnamestring, usernamestring, passwordstring);Log.i("login",jsonobject.toString());}});}@Overridepublic boolean onCreateOptionsMenu(Menu menu) {// Inflate the menu; this adds items to the action bar if it is present.return true;}}

?//ServiceLink.class

import java.io.BufferedReader; import java.io.IOException; import java.io.InputStream; import java.io.InputStreamReader; import java.io.UnsupportedEncodingException; import java.util.ArrayList; 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.HttpPost; import org.apache.http.impl.client.DefaultHttpClient; import org.apache.http.message.BasicNameValuePair; import org.apache.http.protocol.HTTP; import org.json.JSONException; import org.json.JSONObject;import android.util.Log;public final class ServiceLink { /* 功能：連接服務器API：link(String url);get(String bundle, String value); */private String url = null;ServiceLink(){Log.i("ServiceLink", "ServiceLink");}public void setURL(String urll){this.url = urll;Log.i("ServiceLink",url);}public JSONObject serviceLogin(String hostname,String username, String password){List<NameValuePair> params = new ArrayList<NameValuePair>();Log.i("ServiceLink","add params to ArrayList");params.add(new BasicNameValuePair("operate","login"));params.add(new BasicNameValuePair("hostname", hostname));params.add(new BasicNameValuePair("username",username));params.add(new BasicNameValuePair("password", password));Log.i("ServiceLink","ready to return value from putParamsToHttp! ");return putParamsToHttp(params);}public JSONObject serviceClean(){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "clean"));return putParamsToHttp(params);}public JSONObject serviceSearch(String form, String field, String value){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "search"));params.add(new BasicNameValuePair("form", form));params.add(new BasicNameValuePair("field", field));params.add(new BasicNameValuePair("value", value));return putParamsToHttp(params);}public JSONObject serviceRead(String form){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "read"));params.add(new BasicNameValuePair("form", form));return putParamsToHttp(params);}public JSONObject serviceRead(String form, String base, String num){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "read"));params.add(new BasicNameValuePair("form", form));params.add(new BasicNameValuePair("base", base));params.add(new BasicNameValuePair("num", num));return putParamsToHttp(params);}public JSONObject serviceAlter(String form, String field, String id, String value){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "alter"));params.add(new BasicNameValuePair("form", form));params.add(new BasicNameValuePair("field", field));params.add(new BasicNameValuePair("id", id));params.add(new BasicNameValuePair("value", value));return putParamsToHttp(params);}public JSONObject serviceDelete(String id){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "delete"));params.add(new BasicNameValuePair("id", id));return putParamsToHttp(params);} public JSONObject serviceInsert(String form,String device,String port,String vlan,String singleMulti, String function, String destDevice){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "Insert"));params.add(new BasicNameValuePair("form", form));params.add(new BasicNameValuePair("device", device));params.add(new BasicNameValuePair("port", port));params.add(new BasicNameValuePair("vlan", vlan));params.add(new BasicNameValuePair("singleMulti", singleMulti));params.add(new BasicNameValuePair("function", function));params.add(new BasicNameValuePair("destDevice", destDevice));return putParamsToHttp(params);} public JSONObject serviceInsert(String form,String port,String vlan,String singleMulti, String function, String destDevice){List<NameValuePair> params = new ArrayList<NameValuePair>();params.add(new BasicNameValuePair("operate", "Insert"));params.add(new BasicNameValuePair("form", form));params.add(new BasicNameValuePair("port", port));params.add(new BasicNameValuePair("vlan", vlan));params.add(new BasicNameValuePair("singleMulti", singleMulti));params.add(new BasicNameValuePair("function", function));params.add(new BasicNameValuePair("destDevice", destDevice));return putParamsToHttp(params);} public JSONObject putParamsToHttp(List<NameValuePair> params){HttpPost httpPost = new HttpPost(url);InputStream is = null;JSONObject jObj = null;String json = null;Log.i("ServiceLink","ready to put params to http!s");try {//設置httpPost請求參數Log.i("ServiceLink","setEntity");httpPost.setEntity(new UrlEncodedFormEntity(params, HTTP.UTF_8));//Log.i("ServiceLink","execute");HttpResponse httpResponse = new DefaultHttpClient().execute(httpPost);Log.i("ServiceLink","getStatusCode");if(httpResponse.getStatusLine().getStatusCode() == 200){Log.i("ServiceLink","response ok!");HttpEntity httpEntity = httpResponse.getEntity();is = httpEntity.getContent(); Log.i("ServiceLink","getContent");}} catch (UnsupportedEncodingException e) {// TODO Auto-generated catch blockLog.i("ServiceLink", "Link failed --ServiceLink");} catch (ClientProtocolException e) {// TODO Auto-generated catch blockLog.i("ServiceLink", "Link failed --ClientProtocolException");} catch (IOException e) {// TODO Auto-generated catch blockLog.i("ServiceLink", "Link failed --IOException");}try {BufferedReader reader = new BufferedReader(new InputStreamReader(is));Log.i("ServiceLink","new StringBuilder");StringBuilder sb = new StringBuilder();String line = null;while ((line = reader.readLine()) != null) {sb.append(line + "\n");Log.i("ServiceLink",line);}is.close();json = sb.toString();Log.i("ServiceLink",json);} catch (Exception e) {Log.e("Buffer Error", "Error converting result " + e.toString());Log.d("json", json.toString());}// try parse the string to a JSON objecttry {jObj = new JSONObject(json);} catch (JSONException e) {Log.e("JSON Parser", "Error parsing data " + e.toString());}// return JSON Stringreturn jObj;} }

?//php

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<?phpheader("Content-Type:text/html; charset=utf-8");if(!isset($_COOKIE['hostname']))$hostname = "localhost";else $hostname = $_COOKIE['hostname'];if(!isset($_COOKIE['username']))$username = "root";else $username = $_COOKIE['username'];if(!isset($_COOKIE['password']))$password = "";else $password = $_COOKIE['password'];$true = array('success'=>'true');if(!isset($_POST['operate'])){print(json_encode("error():請輸入操作"));die(mysql_error());}else{$operate = $_POST['operate'];switch ($operate){case "login":login($_POST['hostname'],$_POST['username'],$_POST['password']);break;case "clean":clean();break;case "search":search($_POST['form'], $_POST['field'], $_POST['value']);break;case "read":if(!isset($_POST['num']))read1($_POST['form']);else read2($_POST['$form'], $_POST['$base'], $_POST['$num']);break;case "alter":alter($_POST['form'], $_POST['field'], $_POST['id'],$_POST['value']);break;case "delete":delete($_POST['form'],$_POST['id']);break;case "insert":if(isset($_POST['device']))insert1($_POST['form'],$_POST['device'], $_POST['port'], $_POST['vlan'], $_POST['singleMulti'], $_POST['function'], $_POST['destDevice']);else insert2();break;default:print(json_encode("error():請輸入操作"));die(mysql_error());}}function login($login_hostname,$login_username,$login_password){//登錄global $true;$link = @mysql_connect($login_hostname,$login_username,$login_password);if(!$link){print(json_encode("error():數據庫連接失敗"));die(mysql_error());}mysql_query("set names utf8");$selected_db = mysql_select_db("qrcode");if(!$selected_db){die(mysql_error());}setcookie("hostname", $login_hostname, time()+ 9999999);setcookie("username", $login_username, time()+ 9999999);setcookie("password", $login_password, time()+ 9999999);print(json_encode($true));return "true";}function clean(){//清楚cookiesmysql_close();setcookie("hostname", $hostname, time()- 9999999);setcookie("username", $username, time()- 9999999);setcookie("password", $password, time()- 9999999);}function search($form, $field, $value){//查詢global $hostname;global $password;global $username;login($hostname,$username,$password);$sql="select * from $form where $field = $value";$result = mysql_query($sql);if(!$result){print(json_encode("error():數據庫查詢失敗"));die(mysql_error());}while($e=mysql_fetch_assoc($result))$output[]=$e; print(json_encode($output)); mysql_close();print(json_encode($true));return "true";}function read1($form){if(read2($form, 0, 5)){print(json_encode($true));return "true";}else die(mysql_error());}function read2($form, $base, $num){//讀取global $hostname;global $password;global $username;login($hostname,$username,$password);$sql = "select * from `$form` LIMIT $base, $num";$result = mysql_query($sql);if(!$result){print(json_encode("error():數據庫讀取失敗"));die(mysql_error());}while($e=mysql_fetch_assoc($result))$output[]=$e; print(json_encode($output)); mysql_close();print(json_encode($true));return "true";}function alter($form, $field, $id,$value){//修改global $hostname;global $password;global $username;login($hostname,$username,$password);$sql = "UPDATE `$form` SET `$field`=$value WHERE `id` = $id";$result = mysql_query($sql);if(!$result){print(json_encode("error():數據庫更新失敗"));die(mysql_error());}print(json_encode("alter success"));mysql_close();print(json_encode($true));return "true";}function delete($form,$id){//刪除global $hostname;global $password;global $username;login($hostname,$username,$password);$sql = "delete from `$form` where `$id` = $id";$result = mysql_query($sql);if(!$result ){print(json_encode("error():數據庫刪除失敗"));die(mysql_error());}print(json_encode("delete success"));mysql_close();print(json_encode($true));return "true";}function insert1($form,$device, $port, $vlan, $singleMulti, $function, $destDevice){//插入global $hostname;global $password;global $username;login($hostname,$username,$password);$sql="INSERT INTO `form`(`device`, `port`, `VLAN`, `singleMultiMode`, `function`, `destDeviceOrPort`) VALUES ($device,$port,$vlan,$singleMulti,$function,$destDevice)";$result = mysql_query($sql);if(!$result ){print(json_encode("error():數據庫插入失敗"));die(mysql_error());}print(json_encode("insert success"));mysql_close();print(json_encode($true));return "true";}function insert2($form, $port, $vlan, $singleMulti, $function, $destDevice){//插入global $hostname;global $password;global $username;login($hostname,$username,$password);$sql="INSERT INTO `form`(`port`, `VLAN`, `singleMultiMode`, `function`, `destDeviceOrPort`) VALUES ($port,$vlan,$singleMulti,$function,$destDevice)";$result = mysql_query($sql);if(!$result ){print(json_encode("error():數據庫插入失敗"));die(mysql_error());}print(json_encode("insert success"));mysql_close();print(json_encode($true));return "true";} ?>

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轉載于:https://www.cnblogs.com/GaiDynasty/archive/2013/03/08/2949117.html

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