swing—我在java中将csv读入数组，试图将数组的内容设置到jcombobox中

wj8zmpe1  于 2021-07-06  发布在  Java
关注(0)|答案(1)|浏览(407)

我已经用java将csv文件读入数组。我这样做是为了得到 regPlate 专栏，希望把所有的 regPlates . 我在试着 allRegPlates 等于 regPlates[0] 因为当我打印的时候 regPlates[0] 在cli中，它显示所有的车牌列。
这是我的csv。csv图片
这是我的密码：
汽车.java

  1. package prototype;
  3. import java.util.ArrayList;
  5. import java.util.Arrays;
  6. import java.util.*;
  7. import java.util.Scanner;
  8. import java.io.FileReader;
  9. import java.io.BufferedReader;
  10. import java.io.FileInputStream;
  11. import java.io.DataInputStream;
  13. import java.io.File;
  14. import java.io.FileNotFoundException;
  15. import java.io.PrintWriter;
  16. import java.io.IOException;
  18. public class Cars {
  20.     public String regPlate;
  21.     public double price;
  22.     public String make;
  23.     public String model;
  24.     public String fType;
  25.     public String colour;
  26.     public int mileage;
  27.     public int prevOwners;
  28.     public double mpg;
  29.     public double noughttosixty;
  30.     public int bhp;
  31.     public int maxSpeed;
  32.     public String feature1;
  33.     public String feature2;
  34.     public String feature3;
  35.     public String feature4;
  36.     public boolean sold;
  37.     public double boughtFor;
  38.     public double profit;
  40.     public String[] regPlates;
  41.     public String allRegPlates;
  43.     Scanner input = new Scanner(System.in);
  44.     public List<String[]> line = new ArrayList<String[]>();
  45.     String lines = "";
  47.     public String thisLine;
  49.     public List<String> getAllRegPlates() 
  50.     {
  52.         String currentLine = "";
  53.         List<String> allRegPlates = new ArrayList<>();
  54.         String[] tempRegPlates;
  56.         try (BufferedReader br = new BufferedReader(new FileReader("Cars.csv"))) {
  58.             while ((currentLine = br.readLine()) != null) {
  59.                 tempRegPlates = currentLine.split(",");
  60.                 System.out.println(tempRegPlates[0]);
  61.                 // Add all found plates to your collection
  62.                 allRegPlates.add(tempRegPlates[0]);
  63.             }
  64.         } catch (IOException e) {
  65.             e.printStackTrace();
  66.         }
  68.         return allRegPlates;
  69.     }

图形用户界面.java

  1. Cars cars = new Cars();
  3.         List<String> plates = cars.getAllRegPlates(); // get all the plates as list
  4.         String[] platesAsArray = (String[]) plates.toArray();
  6.         setDefaultCloseOperation(JFrame.EXIT_ON_CLOSE);
  7.         setBounds(500, 200, 1000, 600);
  8.         contentPane = new JPanel();
  9.         contentPane.setBackground(Color.BLACK);
  10.         contentPane.setBorder(new EmptyBorder(5, 5, 5, 5));
  11.         setContentPane(contentPane);
  12.         GridBagLayout gbl_contentPane = new GridBagLayout();
  13.         gbl_contentPane.columnWidths = new int[]{0, 124, 123, 0, 0, 0, 0, 0, 0, 0, 0, 275, 189, 7, 0};
  14.         gbl_contentPane.rowHeights = new int[]{0, 0, 36, 0, 0, 0, 0, 0, 0, 0, 0, 0, 155, 0};
  15.         gbl_contentPane.columnWeights = new double[]{0.0, 1.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 1.0, Double.MIN_VALUE};
  16.         gbl_contentPane.rowWeights = new double[]{0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, 0.0, Double.MIN_VALUE};
  17.         contentPane.setLayout(gbl_contentPane);
  19.         JComboBox comboBox = new JComboBox(platesAsArray);
  20.         GridBagConstraints gbc_comboBox = new GridBagConstraints();
  21.         gbc_comboBox.insets = new Insets(0, 0, 5, 5);
  22.         gbc_comboBox.fill = GridBagConstraints.HORIZONTAL;
  23.         gbc_comboBox.gridx = 1;
  24.         gbc_comboBox.gridy = 2;
  25.         contentPane.add(comboBox, gbc_comboBox);

这就是我的gui显示的内容
我也得到这个错误：

  1. regPlate
  2. la1 abc
  3. la6 5gb
  4. rifol1
  5. SX72 44
  6. java.lang.ClassCastException: class [Ljava.lang.Object; cannot be cast to class [Ljava.lang.String; ([Ljava.lang.Object; and [Ljava.lang.String; are in module java.base of loader 'bootstrap')
  7.     at prototype.GUI.<init>(GUI.java:98)
  8.     at prototype.GUI$1.run(GUI.java:43)
  9.     at java.desktop/java.awt.event.InvocationEvent.dispatch(InvocationEvent.java:316)
  10.     at java.desktop/java.awt.EventQueue.dispatchEventImpl(EventQueue.java:770)
  11.     at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:721)
  12.     at java.desktop/java.awt.EventQueue$4.run(EventQueue.java:715)
  13.     at java.base/java.security.AccessController.doPrivileged(AccessController.java:391)
  14.     at java.base/java.security.ProtectionDomain$JavaSecurityAccessImpl.doIntersectionPrivilege(ProtectionDomain.java:85)
  15.     at java.desktop/java.awt.EventQueue.dispatchEvent(EventQueue.java:740)
  16.     at java.desktop/java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:203)
  17.     at java.desktop/java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:124)
  18.     at java.desktop/java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:113)
  19.     at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:109)
  20.     at java.desktop/java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:101)
  21.     at java.desktop/java.awt.EventDispatchThread.run(EventDispatchThread.java:90)

任何帮助都将不胜感激。

Javacsvswinguser-interfacecombobox

1条答案

按热度按时间
vpfxa7rd

vpfxa7rd1#

正如在评论中已经指出的，第一件事就是修正你的输入。在getallregplates（）中，实际上并没有将所有输入汇总到一个集合或数组中。此外，你还返回颜色，这甚至没有定义在那里。
这是你的 getAllRegPlates() 这将返回一个 List 包含在csv文件中找到的所有图版的字符串

  1. public List<String> getAllRegPlates() {
  3.     String currentLine = "";
  4.     List<String> allRegPlates = new ArrayList<>();
  5.     String[] tempRegPlates;
  7.     try (BufferedReader br = new BufferedReader(new FileReader("Cars.csv"))) {
  9.         while ((currentLine = br.readLine()) != null) {
  10.             tempRegPlates = currentLine.split(",");
  11.             System.out.println(tempRegPlates[0]);
  12.             // Add all found plates to your collection
  13.             allRegPlates.add(tempRegPlates[0]);
  14.         }
  15.     } catch (IOException e) {
  16.         e.printStackTrace();
  17.     }
  18.     // finally, return the list of regplates
  19.     return allRegPlates;
  20. }

由于输入现在应该起作用，下一步将是更正 JComboBox . 这看起来像这样：

  1. Cars cars = new Cars();
  2. List<String> plates = cars.getAllRegPlates(); // get all the plates as list
  3. String[] platesAsArray = (String[]) plates.toArray(); // convert to String array
  4. JComboBox comboBox = new JComboBox<String>(platesAsArray); // create the combobox
  5. // finally, do layout stuff and add to your frame / panel
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