安卓通过url访问mysql数据库

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;

public class MainActivity extends AppCompatActivity {

    private static final String DB_URL = "jdbc:mysql://hostname:port/database_name";
    private static final String DB_USER = "username";
    private static final String DB_PASSWORD = "password";

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

        Connection conn = null;
        Statement stmt = null;
        ResultSet rs = null;

        try {
            // 注册驱动程序
            Class.forName("com.mysql.jdbc.Driver");

            // 建立数据库连接
            conn = DriverManager.getConnection(DB_URL, DB_USER, DB_PASSWORD);

            // 执行查询语句
            stmt = conn.createStatement();
            String sql = "SELECT * FROM table_name";
            rs = stmt.executeQuery(sql);

            // 处理查询结果
            while (rs.next()) {
                // 读取数据
                String data = rs.getString("column_name");
                Log.d("Database", data);
            }
        } catch (SQLException | ClassNotFoundException e) {
            e.printStackTrace();
        } finally {
            // 关闭连接
            try {
                if (rs != null) {
                    rs.close();
                }
                if (stmt != null) {
                    stmt.close();
                }
                if (conn != null) {
                    conn.close();
                }
            } catch (SQLException e) {
                e.printStackTrace();
            }
        }
    }
}