如何使用if-else语句确保login.java上的编码更安全？_Java_Android Studio_If Statement_Authentication_Secure Coding

如何使用if-else语句确保login.java上的编码更安全？

java android-studio if-statement authentication

如何使用if-else语句确保login.java上的编码更安全？,java,android-studio,if-statement,authentication,secure-coding,Java,Android Studio,If Statement,Authentication,Secure Coding,我的问题： 1。我想使用if-else语句使登录更加安全 2。但是，我有一个问题，无论谁填写表格，都可以访问欢迎页面。 3。我必须添加什么编码，以确保只有在我的数据库中注册的用户才能访问我的欢迎页面。 4。帮帮我吧，我已经找到了这个问题的很多答案，但都无法正常工作。下面是我的.java文件：Login.java package com.example.lab3; import androidx.appcompat.app.AppCompatActivity; import android.

我的问题：

1。我想使用if-else语句使登录更加安全

2。但是，我有一个问题，无论谁填写表格，都可以访问欢迎页面。

3。我必须添加什么编码，以确保只有在我的数据库中注册的用户才能访问我的欢迎页面。

4。帮帮我吧，我已经找到了这个问题的很多答案，但都无法正常工作。

下面是我的.java文件：Login.java

package com.example.lab3;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class Login extends AppCompatActivity
{
EditText username, password;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    username = findViewById(R.id.etUsername);
    password = findViewById(R.id.etPassword);
}

public void OnLog(View view)
{
    AlertDialog.Builder dialog = new AlertDialog.Builder(this);
    dialog.setTitle("Login Status");
    dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener()
    {
        String Username = username.getText().toString();
        String Password = password.getText().toString();
        String type = "login";

        @Override
        public void onClick(DialogInterface dialogInterface, int i) {

            Background bg = new Background(Login.this);
            bg.execute(type, Username, Password);

            if(Username.equals("") || Password.equals("")) //for user doesnt fill the form
            {
                Toast.makeText(getApplicationContext(), "Username and Password are required!", Toast.LENGTH_LONG).show();
            }
            else if (bg.login(Username, Password))  //I have some error at login
            {
                startActivity(new Intent(getApplicationContext(), Welcome.class));
            }
            else {  
                Toast.makeText(getApplicationContext(), "Login Successful", Toast.LENGTH_LONG).show();
                startActivity(new Intent(getApplicationContext(), Welcome.class)); //can access Welcome.class while the user's account is not available on phpAdmin database.

            }
        }
    });
    dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            finish();
        }
    });
    dialog.show();
}

public void OnReg(View view) {
    startActivity(new Intent(getApplicationContext(), Register.class));
}
}

package com.example.lab3;

import android.app.AlertDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.EditText;

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 Background extends AsyncTask<String,Void,String> {

Context context;
AlertDialog alertDialog;

Background(Context ctx) {
    context = ctx;
}

@Override
protected String doInBackground(String... params)
{
    String type = params[0];
    String login_url = "http://172.20.10.4/LoginLab3.php";
    String reg_url = "http://172.20.10.4/RegisterLab3.php";
    if (type.equals("login")) {
        try {
            String username = params[1];
            String password = params[2];
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("GET");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String post_data = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&"
                    + URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");
            bufferedWriter.write(post_data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "ISO-8859-1"));
            String result = "";
            String line = "";
            while ((line = bufferedReader.readLine()) != null)
            {
                result += line;
            }
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return result;
        }
        catch (MalformedURLException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
    else if(type.equals("register"))
    {
        try {
            String name = params[1];
            String surname = params[2];
            String age = params[3];
            String username = params[4];
            String password = params[5];
            URL url = new URL(reg_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String post_data = URLEncoder.encode("name","UTF-8")+"="+URLEncoder.encode(name,"UTF-8")+"&"
                    +URLEncoder.encode("surname","UTF-8")+"="+URLEncoder.encode(surname,"UTF-8")+"&"
                    +URLEncoder.encode("age","UTF-8")+"="+URLEncoder.encode(age,"UTF-8")+"&"
                    +URLEncoder.encode("username","UTF-8")+"="+URLEncoder.encode(username,"UTF-8")+"&"
                    +URLEncoder.encode("password","UTF-8")+"="+URLEncoder.encode(password,"UTF-8");
            bufferedWriter.write(post_data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"ISO-8859-1"));
            String result="";
            String line="";
            while((line = bufferedReader.readLine())!= null)
            {
                result += line;
            }
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return result;
        }
        catch (MalformedURLException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
    return null;
}

@Override
protected void onPreExecute()
{
    alertDialog = new AlertDialog.Builder(context).create();
    alertDialog.setTitle("Login Status");
}

@Override
protected void onPostExecute(String result)
{
    alertDialog.setMessage(result);
    alertDialog.show();
}

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

我的连接数据库：Background.java

package com.example.lab3;

import androidx.appcompat.app.AppCompatActivity;

import android.app.AlertDialog;
import android.content.DialogInterface;
import android.content.Intent;
import android.os.Bundle;
import android.view.View;
import android.widget.EditText;
import android.widget.Toast;

public class Login extends AppCompatActivity
{
EditText username, password;

@Override
protected void onCreate(Bundle savedInstanceState)
{
    super.onCreate(savedInstanceState);
    setContentView(R.layout.activity_login);

    username = findViewById(R.id.etUsername);
    password = findViewById(R.id.etPassword);
}

public void OnLog(View view)
{
    AlertDialog.Builder dialog = new AlertDialog.Builder(this);
    dialog.setTitle("Login Status");
    dialog.setPositiveButton("Ok", new DialogInterface.OnClickListener()
    {
        String Username = username.getText().toString();
        String Password = password.getText().toString();
        String type = "login";

        @Override
        public void onClick(DialogInterface dialogInterface, int i) {

            Background bg = new Background(Login.this);
            bg.execute(type, Username, Password);

            if(Username.equals("") || Password.equals("")) //for user doesnt fill the form
            {
                Toast.makeText(getApplicationContext(), "Username and Password are required!", Toast.LENGTH_LONG).show();
            }
            else if (bg.login(Username, Password))  //I have some error at login
            {
                startActivity(new Intent(getApplicationContext(), Welcome.class));
            }
            else {  
                Toast.makeText(getApplicationContext(), "Login Successful", Toast.LENGTH_LONG).show();
                startActivity(new Intent(getApplicationContext(), Welcome.class)); //can access Welcome.class while the user's account is not available on phpAdmin database.

            }
        }
    });
    dialog.setNegativeButton("Cancel", new DialogInterface.OnClickListener() {
        @Override
        public void onClick(DialogInterface dialogInterface, int i) {
            finish();
        }
    });
    dialog.show();
}

public void OnReg(View view) {
    startActivity(new Intent(getApplicationContext(), Register.class));
}
}

package com.example.lab3;

import android.app.AlertDialog;
import android.content.Context;
import android.os.AsyncTask;
import android.widget.EditText;

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 Background extends AsyncTask<String,Void,String> {

Context context;
AlertDialog alertDialog;

Background(Context ctx) {
    context = ctx;
}

@Override
protected String doInBackground(String... params)
{
    String type = params[0];
    String login_url = "http://172.20.10.4/LoginLab3.php";
    String reg_url = "http://172.20.10.4/RegisterLab3.php";
    if (type.equals("login")) {
        try {
            String username = params[1];
            String password = params[2];
            URL url = new URL(login_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection) url.openConnection();
            httpURLConnection.setRequestMethod("GET");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String post_data = URLEncoder.encode("username", "UTF-8") + "=" + URLEncoder.encode(username, "UTF-8") + "&"
                    + URLEncoder.encode("password", "UTF-8") + "=" + URLEncoder.encode(password, "UTF-8");
            bufferedWriter.write(post_data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "ISO-8859-1"));
            String result = "";
            String line = "";
            while ((line = bufferedReader.readLine()) != null)
            {
                result += line;
            }
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return result;
        }
        catch (MalformedURLException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
    else if(type.equals("register"))
    {
        try {
            String name = params[1];
            String surname = params[2];
            String age = params[3];
            String username = params[4];
            String password = params[5];
            URL url = new URL(reg_url);
            HttpURLConnection httpURLConnection = (HttpURLConnection)url.openConnection();
            httpURLConnection.setRequestMethod("POST");
            httpURLConnection.setDoOutput(true);
            httpURLConnection.setDoInput(true);
            OutputStream outputStream = httpURLConnection.getOutputStream();
            BufferedWriter bufferedWriter = new BufferedWriter(new OutputStreamWriter(outputStream, "UTF-8"));
            String post_data = URLEncoder.encode("name","UTF-8")+"="+URLEncoder.encode(name,"UTF-8")+"&"
                    +URLEncoder.encode("surname","UTF-8")+"="+URLEncoder.encode(surname,"UTF-8")+"&"
                    +URLEncoder.encode("age","UTF-8")+"="+URLEncoder.encode(age,"UTF-8")+"&"
                    +URLEncoder.encode("username","UTF-8")+"="+URLEncoder.encode(username,"UTF-8")+"&"
                    +URLEncoder.encode("password","UTF-8")+"="+URLEncoder.encode(password,"UTF-8");
            bufferedWriter.write(post_data);
            bufferedWriter.flush();
            bufferedWriter.close();
            outputStream.close();
            InputStream inputStream = httpURLConnection.getInputStream();
            BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream,"ISO-8859-1"));
            String result="";
            String line="";
            while((line = bufferedReader.readLine())!= null)
            {
                result += line;
            }
            bufferedReader.close();
            inputStream.close();
            httpURLConnection.disconnect();
            return result;
        }
        catch (MalformedURLException e)
        {
            e.printStackTrace();
        }
        catch (IOException e)
        {
            e.printStackTrace();
        }
    }
    return null;
}

@Override
protected void onPreExecute()
{
    alertDialog = new AlertDialog.Builder(context).create();
    alertDialog.setTitle("Login Status");
}

@Override
protected void onPostExecute(String result)
{
    alertDialog.setMessage(result);
    alertDialog.show();
}

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

package com.example.lab3；
导入android.app.AlertDialog；
导入android.content.Context；
导入android.os.AsyncTask；
导入android.widget.EditText；
导入java.io.BufferedReader；
导入java.io.BufferedWriter；
导入java.io.IOException；
导入java.io.InputStream；
导入java.io.InputStreamReader；
导入java.io.OutputStream；
导入java.io.OutputStreamWriter；
导入java.net.HttpURLConnection；
导入java.net.MalformedURLException；
导入java.net.URL；
导入java.net.urlcoder；
公共类后台任务{
语境；
警报对话框警报对话框；
背景（上下文ctx）{
上下文=ctx；
}
@凌驾
受保护的字符串doInBackground（字符串…参数）
{
字符串类型=参数[0]；
字符串登录\u url=”http://172.20.10.4/LoginLab3.php";
字符串注册表url=”http://172.20.10.4/RegisterLab3.php";
if（type.equals（“登录”））{
试一试{
字符串username=params[1]；
字符串密码=参数[2]；
URL=新URL（登录\ URL）；
HttpURLConnection HttpURLConnection=（HttpURLConnection）url.openConnection（）；
httpURLConnection.setRequestMethod（“GET”）；
httpURLConnection.setDoOutput（true）；
httpURLConnection.setDoInput（true）；
OutputStream OutputStream=httpURLConnection.getOutputStream（）；
BufferedWriter BufferedWriter=新的BufferedWriter（新的OutputStreamWriter（outputStream，UTF-8））；
字符串post_data=URLEncoder.encode（“用户名”，“UTF-8”）+“=”+URLEncoder.encode（用户名，“UTF-8”）+“&”
+urlcoder.encode（“密码”，“UTF-8”）+“=”+urlcoder.encode（密码，“UTF-8”）；
bufferedWriter.write（post_数据）；
bufferedWriter.flush（）；
bufferedWriter.close（）；
outputStream.close（）；
InputStream InputStream=httpURLConnection.getInputStream（）；
BufferedReader BufferedReader=新的BufferedReader（新的InputStreamReader（inputStream，“ISO-8859-1”）；
字符串结果=”；
字符串行=”；
而（（line=bufferedReader.readLine（））！=null）
{
结果+=行；
}
bufferedReader.close（）；
inputStream.close（）；
httpURLConnection.disconnect（）；
返回结果；
}
捕获（格式错误）
{
e、 printStackTrace（）；
}
捕获（IOE异常）
{
e、 printStackTrace（）；
}
}
else if（type.equals（“寄存器”））
{
试一试{
字符串名称=参数[1]；
字符串姓氏=参数[2]；
字符串年龄=参数[3]；
字符串username=params[4]；
字符串密码=参数[5]；
URL=新URL（注册URL）；
HttpURLConnection HttpURLConnection=（HttpURLConnection）url.openConnection（）；
httpURLConnection.setRequestMethod（“POST”）；
httpURLConnection.setDoOutput（true）；
httpURLConnection.setDoInput（true）；
OutputStream OutputStream=httpURLConnection.getOutputStream（）；
BufferedWriter BufferedWriter=新的BufferedWriter（新的OutputStreamWriter（outputStream，UTF-8））；
字符串post_data=URLEncoder.encode（“名称”，“UTF-8”）+”=“+URLEncoder.encode（名称，“UTF-8”）+”&”
+URLEncoder.encode（“姓氏”，“UTF-8”）+”=“+URLEncoder.encode（姓氏，“UTF-8”）+”&”
+URLEncoder.encode（“年龄”，“UTF-8”）+”=“+URLEncoder.encode（年龄，“UTF-8”）+”&”
+URLEncoder.encode（“用户名”，“UTF-8”）+”=“+URLEncoder.encode（用户名，“UTF-8”）+”&”
+urlcoder.encode（“密码”，“UTF-8”）+“=”+urlcoder.encode（密码，“UTF-8”）；
bufferedWriter.write（post_数据）；
bufferedWriter.flush（）；
bufferedWriter.close（）；
outputStream.close（）；
InputStream InputStream=httpURLConnection.getInputStream（）；
BufferedReader BufferedReader=新的BufferedReader（新的InputStreamReader（inputStream，“ISO-8859-1”）；
字符串结果=”；
字符串行=”；
而（（line=bufferedReader.readLine（））！=null）
{
结果+=行；
}
bufferedReader.close（）；
inputStream.close（）；
httpURLConnection.disconnect（）；
返回结果；
}
捕获（格式错误）
{
e、 printStackTrace（）；
}
捕获（IOE异常）
{
e、 printStackTrace（）；
}
}
返回null；
}
@凌驾
受保护的void onPreExecute（）
{
alertDialog=新建alertDialog.Builder（context.create（）；
alertDialog.setTitle（“登录状态”）；
}
@凌驾
受保护的void onPostExecute（字符串结果）
{
alertDialog.setMessage（结果）；
alertDialog.show（）；
}
@凌驾
受保护的void onProgressUpdate（void…值）
{
super.onProgressUpdate（值）；
}
}

提供您的后台类代码这里没有问题。我已经添加了Background.java