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我想通过servlet使用Json来认证从android studio到mySQL的应用程序。 我继续得到这个解析错误。以下是我的代码片段。请帮帮我。解析数据时出错org.json.JSONException：java.lang.String类型的值 无法转换为JSONObject
MainActivity类别书面的Android工作室
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public class MainActivity extends ActionBarActivity {
EditText uname, password;
Button submit;
JSONParser jParser = new JSONParser();
JSONObject json;
private static String url_login = "http://192.168.10.125:8080/CabbCallLogin/LoginServlet";
//JSONArray incoming_msg = null;
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
findViewsById();
submit.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View args0) {
// execute method invokes doInBackground() where we open a Http URL connection using the given Servlet URL
//and get output response from InputStream and return it.
new Login().execute();
}
});
}
private void findViewsById() {
uname = (EditText) findViewById(R.id.txtUser);
password = (EditText) findViewById(R.id.txtPass);
submit = (Button) findViewById(R.id.button1);
}
private class Login extends AsyncTask<String, String, String> {
@Override
protected String doInBackground(String... args) {
Log.e("Error001" , "I am in background");
// Getting username and password from user input
String username = uname.getText().toString();
String pass = password.getText().toString();
Log.e("Error004", "I have got the uname,pass");
List<NameValuePair> params = new ArrayList<NameValuePair>();
params.add(new BasicNameValuePair("u",username));
params.add(new BasicNameValuePair("p",pass));
Log.e("Error00", "I have got the name value pairs");
json = jParser.makeHttpRequest(url_login, "GET", params);
Log.e("Error00" , "I have sent the request");
String s=null;
try{
s= json.getString("info");
Log.e("Msg", json.getString("info"));
Log.e("Error" , "I am in the try catch");
if(s.equals("success")){
Log.e("Error1" , "I am in the if try catch");
Intent login = new Intent(getApplicationContext(), Welcome.class);
login.addFlags(Intent.FLAG_ACTIVITY_CLEAR_TOP);
startActivity(login);
finish();
}else{
Log.e("Error2" , "I am in the else try catch");
ErrorMessage("Error" , "I m in the else part of login");
}
}catch (JSONException e){
Log.e("Error3" , "I am in the json try catch");
e.printStackTrace();
ErrorMessage("Error", "I m in the json exception part of login");
}
return null;
}
}
private void ErrorMessage(String Title , String Message){
AlertDialog.Builder alertbuilder = new AlertDialog.Builder(MainActivity.this);
alertbuilder.setMessage("Incorrect Credentials");
alertbuilder.setPositiveButton("Ok", null);
alertbuilder.show();
}
@Override
public boolean onCreateOptionsMenu(Menu menu) {
// Inflate the menu; this adds items to the action bar if it is present.
getMenuInflater().inflate(R.menu.menu_main, menu);
return true;
}
@Override
public boolean onOptionsItemSelected(MenuItem item) {
// Handle action bar item clicks here. The action bar will
// automatically handle clicks on the Home/Up button, so long
// as you specify a parent activity in AndroidManifest.xml.
int id = item.getItemId();
//noinspection SimplifiableIfStatement
if (id == R.id.action_settings) {
return true;
}
return super.onOptionsItemSelected(item);
}
}
------------------------------------------
JSONParser class
public class JSONParser {
static InputStream is = null;
static JSONObject jObj = null;
static String json = "";
static InputStream iStream = null;
static JSONArray jarray = null;
public JSONParser() {
}
public JSONObject makeHttpRequest(String url_login, String method,
List<NameValuePair> params) {
// Making HTTP request
Log.e("Error003" , "I am in the JSONOBJECT class");
try {
if(method == "POST"){
// request method is POST
// defaultHttpClient
Log.e("Error003" , "I am in the JSONOBJECT post method");
DefaultHttpClient httpClient = new DefaultHttpClient();
HttpPost httpPost = new HttpPost(url_login);
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
Log.e("Error003" , "I am in the JSONOBJECT get method");
DefaultHttpClient httpClient = new DefaultHttpClient();
String paramString = URLEncodedUtils.format(params, "utf-8");
url_login += "?" + paramString;
HttpGet httpGet = new HttpGet(url_login);
HttpResponse httpResponse = httpClient.execute(httpGet);
HttpEntity httpEntity = httpResponse.getEntity();
is = httpEntity.getContent();
Log.e("Error004" , "I am at end the JSONOBJECT get method");
}
} catch (UnsupportedEncodingException e) {
e.printStackTrace();
}catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try{
Log.e("Error003" , "I am in the Buffer class");
BufferedReader reader = new BufferedReader(new InputStreamReader (is, "UTF-8"), 8);
Log.e("Error004" , "I am in the Buffer class");
StringBuilder sb = new StringBuilder();
Log.e("Error005" , "I am in the Buffer class");
String line = null;
while ((line = reader.readLine()) != null) {
sb.append(line + "\n");
}
is.close();
json = sb.toString();
}catch (Exception e) {
Log.e("Buffer Error1", "Error converting result " + e.toString());
}
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser1", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
public JSONArray getJSONFromUrl(String url_login,String method, List<NameValuePair> params) {
StringBuilder builder = new StringBuilder();
HttpClient client = new DefaultHttpClient();
HttpGet httpGet = new HttpGet(url_login);
try{
HttpResponse response = client.execute(httpGet);
StatusLine statusLine = response.getStatusLine();
int statusCode = statusLine.getStatusCode();
if (statusCode == 200) {
HttpEntity entity = response.getEntity();
InputStream content = entity.getContent();
BufferedReader reader = new BufferedReader(new InputStreamReader(content));
String line;
while ((line = reader.readLine()) != null) {
builder.append(line);
}
} else {
Log.e("==>", "Failed to download file");
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
}
try {
jarray = new JSONArray(builder.toString());
} catch (JSONException e) {
Log.e("JSON Parser2", "Error parsing data " + e.toString());
}
// return JSON Object
return jarray;
}
public JSONObject makeHttpRequest2(String url_login) {
// 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_login);
// 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, "UTF-8"), 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 Error2", "Error converting result " + e.toString());
}
// try parse the string to a JSON object
try {
jObj = new JSONObject(json);
} catch (JSONException e) {
Log.e("JSON Parser3", "Error parsing data " + e.toString());
}
// return JSON String
return jObj;
}
}
错误不在你的代码中，而在你的数据中。检查你试图解析为JSON的文本，看看是否有一些非ASCII字符（例如带有重音符号或类似字母的字母）并尝试以某种方式消除它们 –
您正在通过json – Gunaseelan
@MisaLazovic解析字符串，你说我即将通过一个非ASCII？你可以请别针？ –