问题

我正在制作一个小程序，矩阵动画和字符渲染在一段时间后停止工作。我认为随机操作太慢了，因为如果你做同样的事情，但不使用随机，并在“for”循环中获取字符，则一切正常运行。

这是我的代码。

import javax.swing.*;
import java.awt.*;
import java.util.SplittableRandom;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class TestClass {

    // ...（代码的其余部分）

    private static void initAlphabet() {
        alphabet = new char[96];
        int n = 0;
        for (char c = '\u30A0'; c <= '\u30FF'; c++) {
            alphabet[n] = c;
            n++;
        }
    }

    private static void setFrame() {
        frame = new JFrame("Matrix Animation");
        frame.setSize(900, 900);
        frame.setLocationRelativeTo(null);
        frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
        frame.setResizable(false);
        frame.setVisible(true);

        frame.add(panel);
    }

    private static void setPanel() {
        panel = new JPanel() {
            @Override
            protected void paintComponent(Graphics g) {
                super.paintComponent(g);

                g.setColor(Color.GREEN);

                for (Columns column : Columns.values()) {
                    g.setFont(column.font);
                    g.drawString(String.valueOf(charToDraw), column.xCoords, 22);
                }
            }
        };
        panel.setBackground(Color.BLACK);
    }

    private static void paintChar() {
        ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
        scheduledExecutorService.scheduleAtFixedRate(() -> {

            charToDraw = alphabet[random.nextInt(97)];

            panel.repaint();

        }, 0, 200, TimeUnit.MILLISECONDS);
    }

    private static void setCoordColumn() {
        int n = 0;
        for (Columns column : Columns.values()) {
            column.xCoords = n;
            column.font = new Font("ms mincho", Font.ROMAN_BASELINE, random.nextInt(10) + 12);
            n += 30;
        }
    }
}

import java.awt.*;

public enum Columns {
    Column1,
    Column2,
    Column3,
    // ...（省略了其余的列）

    public int xCoords;
    public Font font;
}

我不知道如何进行优化。此外，在绘制符号时使用循环可能不是最优解决方案。但目前来看，Graphics g 是能够处理的。

谢谢)

<details>
<summary>英文:</summary>
I&#39;m making a small program Matrix Animation and - Character rendering stops working after a while. I think that Random is too slow, because if you do the same thing, but not with Random and take characters in the &quot;for&quot; loop, everything works fine.
It&#39;s my code.

import javax.swing.;
import java.awt.;
import java.util.SplittableRandom;
import java.util.concurrent.Executors;
import java.util.concurrent.ScheduledExecutorService;
import java.util.concurrent.TimeUnit;

public class TestClass {

private static JFrame frame;
private static JPanel panel;
private static volatile char charToDraw = '\u30A0';
private static  char[] alphabet;
private static SplittableRandom random = new SplittableRandom();
public static void main(String[] args) {
initAlphabet();
setCoordColumn();
setPanel();
setFrame();
paintChar();
}
private static void initAlphabet() {
alphabet = new char[96];
int n = 0;
for (char c = '\u30A0'; c <= '\u30FF'; c++) {
alphabet[n] = c;
n++;
}
}
private static void setFrame() {
frame = new JFrame("Matrix Animation");
frame.setSize(900, 900);
frame.setLocationRelativeTo(null);
frame.setDefaultCloseOperation(WindowConstants.EXIT_ON_CLOSE);
frame.setResizable(false);
frame.setVisible(true);
frame.add(panel);
}
private static void setPanel() {
panel = new JPanel() {
@Override
protected void paintComponent(Graphics g) {
super.paintComponent(g);
g.setColor(Color.GREEN);
for (Columns column : Columns.values()) {
g.setFont(column.font);
g.drawString(String.valueOf(charToDraw), column.xCoords, 22);
}
}
};
panel.setBackground(Color.BLACK);
}
private static void paintChar() {
ScheduledExecutorService scheduledExecutorService = Executors.newSingleThreadScheduledExecutor();
scheduledExecutorService.scheduleAtFixedRate(() -> {
charToDraw = alphabet[random.nextInt(97)];
panel.repaint();
}, 0, 200, TimeUnit.MILLISECONDS);
}
private static void setCoordColumn() {
int n = 0;
for (Columns column : Columns.values()) {
column.xCoords = n;
column.font = new Font("ms mincho", Font.ROMAN_BASELINE, random.nextInt(10) + 12);
n += 30;
}
}

}

import java.awt.*;

public enum Columns {
Column1,
Column2,
Column3,
Column4,
Column5,
Column6,
Column7,
Column8,
Column9,
Column10,
Column11,
Column12,
Column13,
Column14,
Column15,
Column16,
Column17,
Column18,
Column19,
Column20,
Column21,
Column22,
Column23,
Column24,
Column25,
Column26,
Column27,
Column28,
Column29,
Column30;

public int xCoords;
public Font font;

}

I don't know how to optimize it.
Also, a loop in drawing a symbol is probably not the optimal solution. But so far, Graphics g is coping.
Thanks)
</details>
# 答案1
**得分**: 1
问题在于您的字母数组只有长度为96（这意味着有效索引从0到95，包括0和95）：
```java
alphabet = new char[96];

但是在您的 paintChar() 方法中，您将其视为包含97个元素：

charToDraw = alphabet[random.nextInt(97)];

一旦随机生成器返回96，这段代码将抛出 ArrayIndexOutOfBoundsException 异常。

当异常发生时，计划的线程会自动终止。

要解决这个问题，请用以下代码替换上述行：

charToDraw = alphabet[random.nextInt(alphabet.length)];

alphabet = new char[96];

charToDraw = alphabet[random.nextInt(97)];

charToDraw = alphabet[random.nextInt(alphabet.length)];