如何减少从 postgresql 检索数据的时间？

Question

代码正在运行，但从 postgresql 服务器检索仅 1 个视频的数据需要 14-16 秒。我认为可能有一种适当的方法来检索数据。请帮我解决一下这个。 谢谢。

FreeClassesAdapter.java

import android.app.Activity;
import android.content.Intent;
import android.view.LayoutInflater;
import android.view.View;
import android.view.ViewGroup;
import android.widget.Button;
import android.widget.ImageView;
import android.widget.TextView;

import androidx.annotation.NonNull;
import androidx.recyclerview.widget.RecyclerView;

import com.android.volley.RequestQueue;
import com.athrved.masterclass.PlayerActivity;
import com.athrved.masterclass.R;
import com.squareup.picasso.Picasso;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.ResultSet;
import java.sql.Statement;
import java.util.ArrayList;

public class FreeclassesAdapter extends RecyclerView.Adapter<FreeclassesAdapter.FreeViewHolder> {

    ArrayList<FreeHelperClass> featloc;
    public static String a,b="FAILED TO LOAD";
    public static String videoId1;
    RequestQueue requestQueue;
    private static String V_id1;

    public FreeclassesAdapter(ArrayList<FreeHelperClass> featloc) {
        this.featloc = featloc;
    }

    @NonNull

    @Override
    public FreeViewHolder onCreateViewHolder(@NonNull ViewGroup parent, int viewType) {
        View view = LayoutInflater.from(parent.getContext()).inflate(R.layout.free_class_card_design,parent,false);
        FreeViewHolder freeViewHolder = new FreeViewHolder(view);

        return freeViewHolder;
    }

    @Override
    public void onBindViewHolder(@NonNull FreeViewHolder holder, int position) {
        FreeHelperClass freeHelperClass = featloc.get(position);

        holder.imagesmall1.setImageResource(freeHelperClass.getImagesmall1());
        holder.imagesmall2.setImageResource(freeHelperClass.getImagesmall2());
        holder.title.setText(freeHelperClass.getTitle());
        holder.topic.setText(freeHelperClass.getTopic());
        holder.author.setText(freeHelperClass.getAuthor());

        Database db=new Database();
        videoId1=V_id1;

        if(position==0){

            Picasso.get().load("https://img.youtube.com/vi/"+videoId1+"/maxresdefault.jpg").into(holder.imagebig);
        }
        if(position==1){

            Picasso.get().load("https://img.youtube.com/vi/lrcqt4RelJ4/maxresdefault.jpg").into(holder.imagebig);
        }
    }

    @Override
    public int getItemCount() {
        return featloc.size();
    }

    public static class FreeViewHolder extends RecyclerView.ViewHolder{
        ImageView imagebig, imagesmall1,imagesmall2;
        TextView topic, author;
        TextView title;
        Button bookmark, bookmark_border;

        public FreeViewHolder(@NonNull final View itemView){
            super(itemView);

            imagebig=itemView.findViewById(R.id.freeimgbig);
            imagesmall1=itemView.findViewById(R.id.freec1_image);
            imagesmall2=itemView.findViewById(R.id.freec2_image);

            bookmark=itemView.findViewById(R.id.bookmarkfree);
            bookmark_border=itemView.findViewById(R.id.bookmarkfree_border);

            title=itemView.findViewById(R.id.freec_title);
            topic=itemView.findViewById(R.id.freec_topic);
            author=itemView.findViewById(R.id.freec_author);



            bookmark_border.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(getAdapterPosition()==0){
                        bookmark_border.setVisibility(View.GONE);
                        bookmark.setVisibility(View.VISIBLE);
                    }
                    if(getAdapterPosition()==1){
                        bookmark_border.setVisibility(View.GONE);
                        bookmark.setVisibility(View.VISIBLE);
                    }
                }
            });

            bookmark.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    if(getAdapterPosition()==0){
                        bookmark_border.setVisibility(View.VISIBLE);
                        bookmark.setVisibility(View.GONE);
                    }
                    if(getAdapterPosition()==1){
                        bookmark_border.setVisibility(View.VISIBLE);
                        bookmark.setVisibility(View.GONE);
                    }
                }
            });

            itemView.setOnClickListener(new View.OnClickListener() {
                @Override
                public void onClick(View v) {
                    videoId1=V_id1;
                    if (getAdapterPosition() == 0) {
                        Intent intent = new Intent(itemView.getContext(), PlayerActivity.class);
                        intent.putExtra("VIDEOID", videoId1);
                        itemView.getContext().startActivity(intent);
                        Activity activity = (Activity) itemView.getContext();
                        activity.overridePendingTransition(android.R.anim.fade_in, android.R.anim.fade_out);

                    }

                    if (getAdapterPosition() == 1) {
                        Intent intent = new Intent(itemView.getContext(), PlayerActivity.class);
                        intent.putExtra("VIDEOID", "lrcqt4RelJ4");
                        itemView.getContext().startActivity(intent);
                        Activity activity = (Activity) itemView.getContext();
                        activity.overridePendingTransition(android.R.anim.fade_in, android.R.anim.fade_out);
                    }

                }
            });

        }



    }

    private class Database {

        private Connection connection;

        private final String host = "ec2-54-158-232-223.compute-1.amazonaws.com";
        private final String database = "ddgaguv61p4m63";
        private final int port = 5432;
        private final String user = "jfeitasqnyuanh";
        private final String pass = "d60b43b4e9ea924c91deb754cf18a51d5948b7a7e58b4e4d0045487767174ad8";
        private String url = "jdbc:postgresql://ec2-54-158-232-223.compute-1.amazonaws.com:5432/ddgaguv61p4m63?sslmode=require&user=jfeitasqnyuanh&password=d60b43b4e9ea924c91deb754cf18a51d5948b7a7e58b4e4d0045487767174ad8";
        private boolean status;

        public Database() {

            this.url = String.format(this.url, this.host, this.port, this.database);
            connect();
            //this.disconnect();
            System.out.println("connection status:" + status);
        }


        private void connect() {
            Thread thread = new Thread(new Runnable() {
                @Override
                public void run() {
                    try {
                        Class.forName("org.postgresql.Driver");
                        connection = DriverManager.getConnection(url, user, pass);
                        status = true;
                        getExtraConnection();
                        System.out.println("connected:" + status);
                    } catch (Exception e) {
                        status = false;
                        System.out.print(e.getMessage());
                        e.printStackTrace();
                    }
                }
            });
            thread.start();
            try {
                thread.join();
            } catch (Exception e) {
                e.printStackTrace();
                this.status = false;
            }
        }

        public Connection getExtraConnection() {
            Connection c = null;
            Statement stmt = null;
            try {
                Class.forName("org.postgresql.Driver");
                c = DriverManager.getConnection(url, user, pass);
                c.setAutoCommit(false);
                System.out.println("Opened database successfully");

                stmt = c.createStatement();
                ResultSet rs = stmt.executeQuery("SELECT * FROM videos WHERE access_count=1;");
                while (rs.next()) {
                    V_id1 = rs.getString("video_id");
//
//                    System.out.println("NAME = " + Name);
//                    System.out.println("BIO = " + Bio);
//                    System.out.println("PHONE = " + Phone);
                    System.out.println();
                }
                rs.close();
                stmt.close();
                c.close();
            } catch (Exception e) {
                System.err.println(e.getClass().getName() + ": " + e.getMessage());
                System.exit(0);
            }
            System.out.println("Records created successfully");
            return c;

        }
    }
}

来自使用 FreeClassesAdapter 的主要活动的代码 - UiUxActivity.java：

import android.graphics.drawable.ColorDrawable;
import android.os.Bundle;
import android.view.MenuItem;
import android.widget.TextView;

import androidx.appcompat.app.AppCompatActivity;
import androidx.recyclerview.widget.GridLayoutManager;
import androidx.recyclerview.widget.LinearLayoutManager;
import androidx.recyclerview.widget.RecyclerView;

import com.athrved.masterclass.FetchData;
import com.athrved.masterclass.R;

import java.util.ArrayList;
import java.util.List;

public class UiuxActivity extends AppCompatActivity {

    TextView abcde;
    TextView ak;
    String tit;
    String urlname,videoID,tita;

    RecyclerView dataList2;
    List<String> titles2;
    List<Integer> images2;
    ImgAdapter2 imgAdapter2;

    RecyclerView popRecycler;
    RecyclerView.Adapter adapter1;

    RecyclerView freeRecycler;
    RecyclerView.Adapter adapter2;

    RecyclerView menRecycler;
    RecyclerView.Adapter adapter3;

    RecyclerView allFewRecycler;
    RecyclerView.Adapter adapter4;

    ArrayList<UiuxAllClasses> allCourseList=new ArrayList<>();

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

        getSupportActionBar().setTitle("UI UX Design");
        getSupportActionBar().setDisplayHomeAsUpEnabled(true);
        getSupportActionBar().setBackgroundDrawable(new ColorDrawable(getResources().getColor(R.color.greyy)));

//        videoID="_vAmKNin0QM";
//        urlname="https://noembed.com/embed?url=https://www.youtube.com/watch?v="+videoID;
//        tita= respo(urlname);


        popRecycler = findViewById(R.id.r1popclass);
        featuredRecycler();
        freeRecycler=findViewById(R.id.r1freeclass);
        freeturedRecycler( tit);
        menRecycler=findViewById(R.id.r3menclass);
        mentoredRecycler();
        allFewRecycler=findViewById(R.id.r4fewalllist);
        allfewRecycler();

        dataList2 = findViewById(R.id.dataList2);

        abcde = findViewById(R.id.tvv1);
        ak=findViewById(R.id.ak);

        titles2 = new ArrayList<>();
        images2 = new ArrayList<>();

        titles2.add("Visual Design");
        titles2.add("UX Design");
        titles2.add("Motion Design");
        titles2.add("Prototyping");
        titles2.add("3D Design");
        titles2.add("Webflow");

        images2.add(R.drawable.visuald_logo);
        images2.add(R.drawable.uiux_logo);
        images2.add(R.drawable.motiond_logo);
        images2.add(R.drawable.mach_logo);
        images2.add(R.drawable.threed_logo);
        images2.add(R.drawable.iot_logo);

        imgAdapter2 = new ImgAdapter2(this,titles2,images2);

        GridLayoutManager gridLayoutManager = new GridLayoutManager(this,2,GridLayoutManager.VERTICAL,false);
        dataList2.setLayoutManager(gridLayoutManager);
        dataList2.setAdapter(imgAdapter2);

    }



    private void featuredRecycler(){

        FetchData fetchData = new FetchData();
        fetchData.execute();

        popRecycler.setHasFixedSize(true);
        popRecycler.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));

        ArrayList<PopHelperClass> popLocatio = new ArrayList<>();

        popLocatio.add(new PopHelperClass(R.drawable.secndone, R.drawable.ai_logo,0,"Color and Color Theory -\nFundamentals of Visual Design","VISUAL DESIGN","Goutham Naik","Um3BhY0oS2c"));
        popLocatio.add(new PopHelperClass(R.drawable.firstone, R.drawable.ai_logo, R.drawable.motiond_logo,"Color and Color Theory -\nFundamentals of Visual Design","UX DESIGN","  Goutham Naik, S. M. Sudhanva Acharya","_vAmKNin0QM"));


        adapter1=new PopclassesAdapter(popLocatio);
         popRecycler.setAdapter(adapter1);

    }

    private void freeturedRecycler(String tita){
        freeRecycler.setHasFixedSize(true);
        freeRecycler.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));

        ArrayList<FreeHelperClass> freeLocatio = new ArrayList<>();

        freeLocatio.add(new FreeHelperClass(R.drawable.ai_logo,0,"Top UX Design Interview Questions","VISUAL DESIGN","S M Sudhanva Acharya"));
        freeLocatio.add(new FreeHelperClass(R.drawable.ai_logo,0,"White Space in Design","VISUAL DESIGN","Abhinav Chikkara"));


        adapter2=new FreeclassesAdapter(freeLocatio);
        freeRecycler.setAdapter(adapter2);

    }

    private void mentoredRecycler(){
        menRecycler.setHasFixedSize(true);
        menRecycler.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.HORIZONTAL, false));

        ArrayList<MenHelperClass> menLocatio = new ArrayList<>();

        menLocatio.add(new MenHelperClass(R.drawable.oneman,"Goutam Naik","CEO, AthrV-Ed"));
        menLocatio.add(new MenHelperClass(R.drawable.twoman,"S M Sudhanva Acharya", "Product Designer, AthrV-Ed"));
        menLocatio.add(new MenHelperClass(R.drawable.threeman,"Abhinav Chikkara", "Founder, 10kilogram"));

        adapter2=new MenAdapter(menLocatio);
        menRecycler.setAdapter(adapter2);

    }

    private void allfewRecycler(){
        allFewRecycler.setHasFixedSize(true);
        allFewRecycler.setLayoutManager(new LinearLayoutManager(this, LinearLayoutManager.VERTICAL, false));

        ArrayList<FewAllHelperClass> fewAllLocatio = new ArrayList<>();

        fewAllLocatio.add(new FewAllHelperClass(R.drawable.webflow_l, R.drawable.ai_logo,"Playing with Grid-\nWeb Design Fundamentals","WEBFLOW","Goutham Naik"));
        fewAllLocatio.add(new FewAllHelperClass(R.drawable.protopie_l, R.drawable.ai_logo,"Protopie for Prototyping","PROTOTYPING\n","Abhinav Chikkara"));
        fewAllLocatio.add(new FewAllHelperClass(R.drawable.afepluslot_l, R.drawable.ai_logo,"Introduction to After Effects\nand Lottie Files","MOTION DESIGN","S.M Sudhanva Acharya"));

        adapter4=new FewAllAdapter(fewAllLocatio);
        allFewRecycler.setAdapter(adapter4);

    }

    @Override
    public boolean onOptionsItemSelected(MenuItem item) {
        switch (item.getItemId()) {
            case android.R.id.home:
                onBackPressed();
                return true;
        }
        return super.onOptionsItemSelected(item);
    }
}

Answer 1

您是否将视频作为 BLOB / CLOB 存储在数据库中。 如果您将视频存储在不同的位置，并将该位置的地址保存在数据库中，该怎么办。这样 Db 必须返回一个字符串，UI/消费者可以负责从路径渲染。