android如何向servlet传两个String类型数据再接收该servlet传回的数据完成登录功能完整代码

以下是一个简单的Android应用程序示例，该应用程序向Servlet传递两个字符串类型的数据，然后接收Servlet返回的数据以完成登录功能。

Android端代码（MainActivity.java）：

public class MainActivity extends AppCompatActivity {
    private EditText mUsernameEditText;
    private EditText mPasswordEditText;
    private Button mLoginButton;

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

        mUsernameEditText = findViewById(R.id.username_edit_text);
        mPasswordEditText = findViewById(R.id.password_edit_text);
        mLoginButton = findViewById(R.id.login_button);

        mLoginButton.setOnClickListener(new View.OnClickListener() {
            @Override
            public void onClick(View view) {
                String username = mUsernameEditText.getText().toString();
                String password = mPasswordEditText.getText().toString();

                // 开启一个异步任务向Servlet传递数据
                new LoginTask().execute(username, password);
            }
        });
    }

    // 定义一个异步任务用于向Servlet传递数据并接收返回数据
    private class LoginTask extends AsyncTask<String, Void, String> {

        @Override
        protected String doInBackground(String... params) {
            String username = params[0];
            String password = params[1];
            String result = "";

            try {
                // 创建一个URL对象
                URL url = new URL("http://your_servlet_url");

                // 创建一个HttpURLConnection对象
                HttpURLConnection connection = (HttpURLConnection) url.openConnection();
                connection.setRequestMethod("POST");
                connection.setDoOutput(true);

                // 构造请求参数
                String data = "username=" + URLEncoder.encode(username, "UTF-8") + "&password=" + URLEncoder.encode(password, "UTF-8");

                // 设置请求参数
                OutputStream outputStream = connection.getOutputStream();
                outputStream.write(data.getBytes());
                outputStream.flush();
                outputStream.close();

                // 读取Servlet返回的数据
                InputStream inputStream = connection.getInputStream();
                BufferedReader bufferedReader = new BufferedReader(new InputStreamReader(inputStream, "UTF-8"));
                String line;
                while ((line = bufferedReader.readLine()) != null) {
                    result += line;
                }
                bufferedReader.close();
                inputStream.close();

                // 断开连接
                connection.disconnect();

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

            return result;
        }

        @Override
        protected void onPostExecute(String result) {
            // 处理Servlet返回的数据
            Toast.makeText(MainActivity.this, result, Toast.LENGTH_SHORT).show();
        }
    }
}

Servlet端代码：

public class LoginServlet extends HttpServlet {
    private static final long serialVersionUID = 1L;

    protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
        // 读取请求参数
        String username = request.getParameter("username");
        String password = request.getParameter("password");

        // 处理登录逻辑
        String result = "";
        if (username.equals("admin") && password.equals("123456")) {
            result = "登录成功";
        } else {
            result = "登录失败";
        }

        // 设置响应编码
        response.setContentType("text/plain;charset=UTF-8");

        // 将结果返回给客户端
        PrintWriter out = response.getWriter();
        out.print(result);
        out.flush();
        out.close();
    }
}

注意替换Android端代码中的"http://your_servlet_url"为您自己的Servlet的URL。在Servlet端代码中，您可以根据实际情况修改登录逻辑以及返回结果。