2021 4 16

云相册服务器dao：

package dao;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.sql.Statement;
import java.util.List;


public class dao {
    public Connection getConnection()
    {
        try {
            Class.forName("com.mysql.cj.jdbc.Driver");
        } catch (ClassNotFoundException e) {
            e.printStackTrace();
        }
        String url = "jdbc:mysql://localhost:3306/groupdb?serverTimezone=GMT%2B8";
        String username = "root";
        String password="123456";
        Connection a=null;
        try {
            a = DriverManager.getConnection(url,username,password);
        } catch (SQLException e) {
            e.printStackTrace();
        }
        return a;
    }
    public boolean login(String id,String passwd)
    {    
        Connection coon=getConnection();
        String sql="select* from user where id = '"+id+"'";//table name
        Statement stmt;
        try {
            stmt = coon.createStatement();
            ResultSet rs=stmt.executeQuery(sql);
            while(rs.next())
            {
                if(passwd.equals(rs.getString("passwd")))
                    {rs.close();stmt.close();coon.close();return true;}
            }
            rs.close();stmt.close();coon.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return false;
        
    }
    public int signin(String id,String passwd)
    {
        if(checkuser(id)==1)
        {
            Connection coon=getConnection();
            String sql;
            sql="insert into user(id,passwd)values(?,?)";//matters' name in table
            PreparedStatement b;
            try {
                b = coon.prepareStatement(sql);
                b.setString(1,id);
                b.setString(2,passwd);
                b.executeUpdate();
                b.close();
                coon.close();
            } catch (SQLException e) {
                // TODO 自动生成的 catch 块
                e.printStackTrace();
            }
            return 1;
        }else
            return 2;
    }
    public int checkuser(String id)
    {
        Connection coon=getConnection();
        String sql="select* from user";
        try {
            PreparedStatement pa=coon.prepareStatement(sql);
            ResultSet rs=pa.executeQuery(sql);
            while(rs.next())
            {
                if(rs.getString("id").equals(id)) return 0;
            }
            rs.close();
            pa.cancel();
            coon.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return 1;
    }
    public void addphoto(String id,String photo,String time)
    {
        Connection coon=getConnection();
        String sql;
        sql="insert into photo(id,photoid,time)values(?,?,?)";//matters' name in table
        PreparedStatement b;
        try {
            b = coon.prepareStatement(sql);
            b.setString(1,id);
            b.setString(2,photo);
            b.setString(3,time);
            b.executeUpdate();
            b.close();
            coon.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }
    public StringBuffer getphotolist(String id)
    {
        String time="";
        StringBuffer a=new StringBuffer(20000);
        Connection coon=getConnection();
        String sql="select* from photo where id = '"+id+"'";
        try {
            PreparedStatement pa=coon.prepareStatement(sql);
            ResultSet rs=pa.executeQuery(sql);
            while(rs.next())
            {
                if(!(rs.getString("time").toString().equals(time)))
                {
                    a.append("$");
                    time=rs.getString("time").toString();
                }
                a.append(rs.getString("photoid").toString()+"+");
            }
            rs.close();
            pa.cancel();
            coon.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return a;
    }
    public StringBuffer gettimelist(String id)
    {
        StringBuffer a=new StringBuffer(20000);
        String time="";
        Connection coon=getConnection();
        String sql="select* from photo where id = '"+id+"'";
        try {
            PreparedStatement pa=coon.prepareStatement(sql);
            ResultSet rs=pa.executeQuery(sql);
            while(rs.next())
            {
                if(!(rs.getString("time").toString().equals(time)))
                {
                    time=rs.getString("time").toString();
                    a.append(time+"+");
                }
            }
            rs.close();
            pa.cancel();
            coon.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return a;
    }
    public int photocount(String id,String time)
    {
        int a=0;
        Connection coon=getConnection();
        String sql="select* from photo where id = '"+id+"' and time = '"+time+"'";
        try {
            PreparedStatement pa=coon.prepareStatement(sql);
            ResultSet rs=pa.executeQuery(sql);
            while(rs.next())
            {
                a++;
            }
            rs.close();
            pa.cancel();
            coon.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return a;
    }
    public String delete(String id)
    {
        Connection coon=getConnection();
        String sql="delete from photo where photoid = '"+id+"'";
        PreparedStatement a1;
        try {
            a1 = coon.prepareStatement(sql);
            a1.execute();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
        return "删除成功";
    }
    public void addcomment(String id,String comment,String time)
    {
        Connection coon=getConnection();
        String sql;
        sql="insert into comment(id,comment,time)values(?,?,?)";//matters' name in table
        PreparedStatement b;
        try {
            b = coon.prepareStatement(sql);
            b.setString(1,id);
            b.setString(2,comment);
            b.setString(3,time);
            b.executeUpdate();
            b.close();
            coon.close();
        } catch (SQLException e) {
            // TODO 自动生成的 catch 块
            e.printStackTrace();
        }
    }
}