内存不足错误

Question

我正在尝试在某人赢得或输掉二十一点游戏后重写文件。每次我运行游戏获胜时，我都会收到此错误：

Exception in thread "AWT-EventQueue-0" java.lang.OutOfMemoryError: Java heap space
    at java.util.Arrays.copyOf(Unknown Source)
    at java.lang.AbstractStringBuilder.expandCapacity(Unknown Source)
    at java.lang.AbstractStringBuilder.ensureCapacityInternal(Unknown Source)
    at java.lang.AbstractStringBuilder.append(Unknown Source)
    at java.lang.StringBuilder.append(Unknown Source)
    at User.setWinnings(User.java:278)
    at Blackjack.addWinnings(Blackjack.java:182)
    at Blackjack.showWinMessage(Blackjack.java:323)
    at Blackjack.showOutcome(Blackjack.java:308)
    at Blackjack.actionPerformed(Blackjack.java:401)
    at javax.swing.AbstractButton.fireActionPerformed(Unknown Source)
    at javax.swing.AbstractButton$Handler.actionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.fireActionPerformed(Unknown Source)
    at javax.swing.DefaultButtonModel.setPressed(Unknown Source)
    at javax.swing.plaf.basic.BasicButtonListener.mouseReleased(Unknown Source)
    at java.awt.Component.processMouseEvent(Unknown Source)
    at javax.swing.JComponent.processMouseEvent(Unknown Source)
    at java.awt.Component.processEvent(Unknown Source)
    at java.awt.Container.processEvent(Unknown Source)
    at java.awt.Component.dispatchEventImpl(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.LightweightDispatcher.retargetMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.processMouseEvent(Unknown Source)
    at java.awt.LightweightDispatcher.dispatchEvent(Unknown Source)
    at java.awt.Container.dispatchEventImpl(Unknown Source)
    at java.awt.Window.dispatchEventImpl(Unknown Source)
    at java.awt.Component.dispatchEvent(Unknown Source)
    at java.awt.EventQueue.dispatchEventImpl(Unknown Source)
    at java.awt.EventQueue.access0(Unknown Source)
    at java.awt.EventQueue.run(Unknown Source)
    at java.awt.EventQueue.run(Unknown Source)

这是 setWinnings 方法的代码

public void setWinnings(int winnings2) {
    winnings = winnings2;

    IO.openInputFile("users.txt");
    String line = IO.readLine();
    StringBuilder newFile = new StringBuilder();

    while(line != null){
        String tokens[] = line.split("%");

        if(tokens.length > 0){

            if(tokens[0].equalsIgnoreCase(this.getUserID())){
                String newLine = tokens[0] + tokens[1]+ tokens[2] + winnings2 + tokens[4]+ tokens[5]+ tokens[6];

                newFile.append(newLine);
                newFile.append("\n");
            } else {
                newFile.append(line);
                newFile.append("\n");
            }

        }
    }

    IO.closeInputFile();
    IO.createOutputFile("users.txt");
    IO.println(newFile.toString());
    IO.closeOutputFile();

}

我已经尝试进入控制面板并将 java 下调用的任何字段更改为 -Xms2048m 或其他内容。知道为什么这行不通吗？

编辑：注意 users.txt 的大小只有 82 个字节。

Answer 1

你有一个循环

while(line != null) { 
    ...
}

但是在循环中你永远不会读到另一行。循环永远不会终止，并且您不断将相同的数据附加到 newFile。最终你消耗了所有的内存。

Answer 2

您只在声明阶段为 line 变量赋值一次：String line = IO.readLine(); 而且它发生在 while 循环之前，在循环中您总是使用相同的第一个 line 而不是用输入文件中的新行重新分配它。

换句话说，while 循环无限运行，或者直到内存耗尽，就像您的情况一样。

您必须在 while 循环范围结束之前添加 line = IO.readLine();。

内存不足错误

Out of Memory Error

java

file-io

heap-memory

overwrite

out-of-memory