Java 我想将android studio连接到mysql

我想在mysql中插入数据，并检索、修改和删除其中的行。我没有任何编程知识，只是一点数据库操作。这个android studio对我来说是一个全新的东西，就像我在关于将android studio连接到mysql的教程中遇到了问题一样。我试着使用我电脑的ip地址，10.0.2.2，127.0.0.1，甚至注册了一个免费的网络主机，但它仍然没有插入数据

另一件事是，显示注册状态的对话框不起作用

我知道的最后一件事是这段代码中的错误，因为当我查看他们的教程时，它起了作用，但我不明白为什么它对我不起作用

我真的很感激你能提供的任何帮助

这是php文件

conn.php
<?php
$db_name = "dbapp";
$mysql_username="root";
$mysql_password="";
$server_name="localhost";
$con = mysqli_connect($server_name,$mysql_username,$mysql_password,$db_name);
?>


register.php
<?php
require "conn.php";
$f_name=$_POST["first_name"];
$m_name=$_POST["middle_name"];
$l_name=$_POST["last_name"];
$email_add=$_POST["emailadd"];
$user_name=$_POST["username"];
$user_pass=$_POST["userpass"];

$sql_query = "insert into tbluser (f_name, m_name, l_name, user_emadd, user_name, user_pass) values('$fname','$mname','$lname','email_add','$user_name','user_pass')";
?>

这里是另一个java类 BackgroundWorker.java

package com.example.*****.myapplication;

import android.app.AlertDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;


public class BackgroundWorker extends AsyncTask<String,Void,String> {
AlertDialog alertDialog;
Context ctx;

BackgroundWorker(Context ctx) {
    this.ctx = ctx;
}

@Override
protected void onPreExecute() {
    super.onPreExecute();
}

@Override
protected String doInBackground(String... params) {
    String reg_url = "http://10.0.2.2/myapp/register.php";
    String login_url = "http://10.0.2.2/myapp/login.php";

    String method = params[0];
    if (method.equals("register")) {
        String fname = params[1];
        String mname = params[2];
        String lname = params[3];
        String emailadd = params[4];
        String username = params[5];
        String userpass = params[6];

              try {
                   URL url = new URL(reg_url);
                   HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                   httpURLConnection.setRequestMethod("POST");
                   httpURLConnection.setDoOutput(true);
                   OutputStream OS = httpURLConnection.getOutputStream();
                   BufferedWriter bufferedwriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
                   String data = URLEncoder.encode("f_name", "UTF-8") + "=" + URLEncoder.encode(fname, "UTF-8") + "&" +
                   URLEncoder.encode("m_name", "UTF-8") + "=" + URLEncoder.encode(mname, "UTF-8") + "&" +
                   URLEncoder.encode("l_name", "UTF-8") + "=" + URLEncoder.encode(lname, "UTF-8") + "&" +
                   URLEncoder.encode("email_add", "UTF-8") + "=" + URLEncoder.encode(emailadd, "UTF-8") + "&" +
                   URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&" +
                   URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(userpass, "UTF-8");



                  bufferedwriter.write(data);
                   bufferedwriter.flush();
                   bufferedwriter.close();
                    OS.close();
                   InputStream IS = httpURLConnection.getInputStream();
                   IS.close();

                  httpURLConnection.disconnect();
                    return "Registration Success";


} catch (MalformedURLException e)
                          {
                            e.printStackTrace();
                          } catch (IOException e)
                          {
                            e.printStackTrace();
                          }

    }

        return null;
    }


    @Override
    protected void onProgressUpdate (Void...values){
        super.onProgressUpdate(values);
    }


@Override
protected void onPostExecute(String result) {

    if(result.equals("Registration Success"))
    {
    Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
    }
    else
    {
    alertDialog.setMessage(result);
    alertDialog.show();
     }
    }
}

---

您的代码易受攻击。请开始使用准备好的参数化查询。将android studio连接到mysql是什么意思？Android studio是Android应用程序的ide。我希望其他设备也能访问数据库。。这就像我要在我的设备中插入数据以更新数据库，而另一台设备将看到所做的更改。您的代码易受攻击。请开始使用准备好的参数化查询。将android studio连接到mysql是什么意思？Android studio是Android应用程序的ide。我希望其他设备也能访问数据库。。这就像我要在我的设备中插入数据来更新数据库，而另一台设备将看到所做的更改。

package com.example.*****.myapplication;

import android.app.AlertDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.Toast;
import java.io.BufferedReader;
import java.io.BufferedWriter;
import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.OutputStream;
import java.io.OutputStreamWriter;
import java.net.HttpURLConnection;
import java.net.MalformedURLException;
import java.net.URL;
import java.net.URLEncoder;


public class BackgroundWorker extends AsyncTask<String,Void,String> {
AlertDialog alertDialog;
Context ctx;

BackgroundWorker(Context ctx) {
    this.ctx = ctx;
}

@Override
protected void onPreExecute() {
    super.onPreExecute();
}

@Override
protected String doInBackground(String... params) {
    String reg_url = "http://10.0.2.2/myapp/register.php";
    String login_url = "http://10.0.2.2/myapp/login.php";

    String method = params[0];
    if (method.equals("register")) {
        String fname = params[1];
        String mname = params[2];
        String lname = params[3];
        String emailadd = params[4];
        String username = params[5];
        String userpass = params[6];

              try {
                   URL url = new URL(reg_url);
                   HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
                   httpURLConnection.setRequestMethod("POST");
                   httpURLConnection.setDoOutput(true);
                   OutputStream OS = httpURLConnection.getOutputStream();
                   BufferedWriter bufferedwriter = new BufferedWriter(new OutputStreamWriter(OS, "UTF-8"));
                   String data = URLEncoder.encode("f_name", "UTF-8") + "=" + URLEncoder.encode(fname, "UTF-8") + "&" +
                   URLEncoder.encode("m_name", "UTF-8") + "=" + URLEncoder.encode(mname, "UTF-8") + "&" +
                   URLEncoder.encode("l_name", "UTF-8") + "=" + URLEncoder.encode(lname, "UTF-8") + "&" +
                   URLEncoder.encode("email_add", "UTF-8") + "=" + URLEncoder.encode(emailadd, "UTF-8") + "&" +
                   URLEncoder.encode("user_name", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&" +
                   URLEncoder.encode("user_pass", "UTF-8") + "=" + URLEncoder.encode(userpass, "UTF-8");



                  bufferedwriter.write(data);
                   bufferedwriter.flush();
                   bufferedwriter.close();
                    OS.close();
                   InputStream IS = httpURLConnection.getInputStream();
                   IS.close();

                  httpURLConnection.disconnect();
                    return "Registration Success";


} catch (MalformedURLException e)
                          {
                            e.printStackTrace();
                          } catch (IOException e)
                          {
                            e.printStackTrace();
                          }

    }

        return null;
    }


    @Override
    protected void onProgressUpdate (Void...values){
        super.onProgressUpdate(values);
    }


@Override
protected void onPostExecute(String result) {

    if(result.equals("Registration Success"))
    {
    Toast.makeText(ctx, result, Toast.LENGTH_LONG).show();
    }
    else
    {
    alertDialog.setMessage(result);
    alertDialog.show();
     }
    }
}

 fname
 mname
 lname
 email_add
 user_name
 user_pass