java - 从结果集中移动数组

Question

我一直在尝试实现我的小 JFrame。基本上，我试图从连接到数据库的结果集构建一个数组，当调用 JFrame 时，小框架会用数据库中的数据填充该数组。

这是我根据周围的情况构建的完整代码，但没有人能为我提供解决方案:(并且在 java 中这肯定是一个例行请求，就像在 PHP 等中一样？

无论如何，如果有人可以为我的大学项目提供帮助，我将永远感激不已。

import java.awt.*;
import java.awt.event.*;
import java.awt.image.BufferedImage;
import java.io.File;
import java.io.IOException;
import javax.imageio.ImageIO;
import javax.swing.*;

import java.sql.Statement;

import java.sql.Connection;
import java.sql.DriverManager;
import java.sql.PreparedStatement;
import java.sql.ResultSet;
import java.sql.SQLException;
import java.util.ArrayList;

public class mainStat extends JPanel {


BufferedImage img;
Double[] eleArray;
private Image bg;
private Image pic;
int alt_1 = normalise(eleArray[0]);
int alt_2 = normalise(eleArray[1]);
int alt_3 = normalise(eleArray[2]);
int alt_4 = normalise(eleArray[3]);
int alt_5 = normalise(eleArray[4]);
int alt_6 = normalise(eleArray[5]);
int alt_7 = normalise(eleArray[6]);
int alt_8 = normalise(eleArray[7]);
int alt_9 = normalise(eleArray[8]);
int alt_0 = normalise(eleArray[9]);
private double shop;
private double bike_shop;
private double accomadation;
int alt = 70;
JLabel label1;
private String display_distance;
static String[] eleResults;

Connection con;
Statement stmt;
ResultSet rs;
static double eleOne;
static double eleTwo;
static double eleThree;
static double eleFour;
static double eleFive;
static double eleSix;
static double eleSeven;
static double eleEight;
static double eleNine;
static double eleZero;


//add in constructor method calling paint(Graphics g)
public mainStat(String distance){
    display_distance = distance;


    label1 = new JLabel();

     setBorder(
             BorderFactory.createCompoundBorder(
                        BorderFactory.createCompoundBorder(
                                        BorderFactory.createTitledBorder("Geo-strip"),
                                        BorderFactory.createEmptyBorder(5,5,5,5)),
                        getBorder()));

     add(label1);


}

    public void paintComponent(Graphics g){
    super.paintComponent(g);

    //main GPS strip 
    try {
           img = ImageIO.read(new File("C:\\test\\geo_strip_box_ex.png"));

           bg = ImageIO.read(new File("C:\\test\\geo_strip_main_ex.png"));
       } catch (IOException e) {
       }

    // Primary indicator box
    g.setColor(Color.WHITE);
    g.fillRect(20, 45, 75, 60);
    g.drawImage(img, 10, 25, null);
    Font font = new Font("Serif", Font.PLAIN, 25);
    g.setColor(Color.BLACK);
    g.setFont(font);
    g.drawString(display_distance, 16, 80);


    // Main Geo-data
    g.drawImage(bg, 10, 25, null);

    // Altitude data
    // Point 1
    g.setColor(Color.RED);
    g.fillOval(105, alt_1, 10, 10);

    // Point 2
    g.setColor(Color.RED);
    g.fillOval(153, alt_2, 10, 10);

    // Point 3
    g.setColor(Color.RED);
    g.fillOval(201, alt_3, 10, 10);

    // Point 4
    g.setColor(Color.RED);
    g.fillOval(249, alt_4, 10, 10);

    // Point 5
    g.setColor(Color.RED);
    g.fillOval(297, alt_5, 10, 10);

    // Point 6
    g.setColor(Color.RED);
    g.fillOval(345, alt_6, 10, 10);

    // Point 7
    g.setColor(Color.RED);
    g.fillOval(394, alt_7, 10, 10);

    // Point 8
    g.setColor(Color.RED);
    g.fillOval(442, alt_8, 10, 10);

    // Point 9
    g.setColor(Color.RED);
    g.fillOval(490, alt_9, 10, 10);

    // Point 10
    g.setColor(Color.RED);
    g.fillOval(540, alt_0, 10, 10);

    // Performance blocks that are build out of an array
    //first block
    g.setColor(Color.BLUE);
    g.fillRect(108, 144, 108, 12);

    //second block
    g.setColor(Color.GREEN);
    g.fillRect(218, 144, 108, 12);

    //third block
    g.setColor(Color.ORANGE);
    g.fillRect(329, 144, 108, 12);

    //forth block
    g.setColor(Color.RED);
    g.fillRect(439, 144, 108, 12);
}
    private int normalise(double altitude){
        //Build the array once correct this part will be changed to allow data base connectivity

                ;
        //Next stage is to find the max values within the array
        double max = eleArray[0];
            for (int i = 0; i < 10; i++)
        if (eleArray[i]> max) max = eleArray[i];


        //Replicate the double loop control for the min values
        double min = eleArray[0];
            for (int i = 0; i < 10; i++)
        if (eleArray[i]< min) min = eleArray[i];

        //Now set the normalised scale; first with the minimum and then the maximum
        double minNalt = 50;
        double maxNalt = 120;

        double result = maxNalt+(altitude-min)*(minNalt-maxNalt)/(max-min);
        int aInt = (int)result;
        return aInt;
    }
        public void Result() {

        String query = "SELECT trkpt_ele FROM routes where trkseg_name = '2011-06-14'";
        try
        {
          // Connect to the database
          //  Similar to php first I need to create a variable to connect to the MySQL database.
          String url = "jdbc:mysql://localhost:3306/bicycleinformationschema"; 

          // Now we need to include username and pass and test mysql database connection
          Connection con = DriverManager.getConnection(url,"root", "kop98mnbvcxz");

          Statement st = con.createStatement();
          ResultSet rs = st.executeQuery(query);
          ArrayList <Double> eleResults = new ArrayList<Double>();

          while (rs.next())

              eleResults.add(rs.getDouble(1));
              Double[] eleArray = eleResults.toArray(new Double[0]);


          }
        catch (SQLException ex)
        {
          System.err.println(ex.getMessage());
        }

      }
}

真心希望有人能帮忙

谢谢

Answer 1

首先，如果您希望经验丰富的程序员能够阅读它，那么您应该尊重缩进和 Java 命名约定(我们是人类，而不是编译器；))

问题:据我所知，您将结果保存在局部变量中，但您没有对它执行任何操作，它不会有任何结果。