作者jerrychai25 (和风散月)
看板java
标题[问题] 我的程式出现这样的错误讯息@@
时间Sun Apr 19 15:31:25 2009
程式的目的是为了把文字档里的东西读出来放进label里，文字档里就一行纯文字
Exception in thread "AWT-EventQueue-0" java.lang.NullPointerException
at GUI.jButtonRankActionPerformed(GUI.java:624)
at GUI.access$1000(GUI.java:16)
at GUI$11.actionPerformed(GUI.java:532)
at
javax.swing.AbstractButton.fireActionPerformed(AbstractButton.java:1995)
at
javax.swing.AbstractButton$Handler.actionPerformed(AbstractButton.java:2318)
at
javax.swing.DefaultButtonModel.fireActionPerformed(DefaultButtonModel.java:387)
at
javax.swing.DefaultButtonModel.setPressed(DefaultButtonModel.java:242)
at
javax.swing.plaf.basic.BasicButtonListener.mouseReleased(BasicButtonListener.java:236)
at java.awt.Component.processMouseEvent(Component.java:6041)
at javax.swing.JComponent.processMouseEvent(JComponent.java:3265)
at java.awt.Component.processEvent(Component.java:5806)
at java.awt.Container.processEvent(Container.java:2058)
at java.awt.Component.dispatchEventImpl(Component.java:4413)
at java.awt.Container.dispatchEventImpl(Container.java:2116)
at java.awt.Component.dispatchEvent(Component.java:4243)
at
java.awt.LightweightDispatcher.retargetMouseEvent(Container.java:4322)
at
java.awt.LightweightDispatcher.processMouseEvent(Container.java:3986)
at java.awt.LightweightDispatcher.dispatchEvent(Container.java:3916)
at java.awt.Container.dispatchEventImpl(Container.java:2102)
at java.awt.Window.dispatchEventImpl(Window.java:2440)
at java.awt.Component.dispatchEvent(Component.java:4243)
at java.awt.EventQueue.dispatchEvent(EventQueue.java:599)
at
java.awt.EventDispatchThread.pumpOneEventForFilters(EventDispatchThread.java:273)
at
java.awt.EventDispatchThread.pumpEventsForFilter(EventDispatchThread.java:183)
at
java.awt.EventDispatchThread.pumpEventsForHierarchy(EventDispatchThread.java:173)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:168)
at
java.awt.EventDispatchThread.pumpEvents(EventDispatchThread.java:160)
at java.awt.EventDispatchThread.run(EventDispatchThread.java:121)
这是出错的main class的code部份
private void jButtonRankActionPerformed(java.awt.event.ActionEvent evt) {
// TODO add your handling code here:
this.setVisible(false);
jFrameRank.setSize(380, 380);
jFrameRank.setVisible(true);
no_1.setText(record.getRank(1));
score_no_1.setText(record.getRankScore(1));
no_2.setText(record.getRank(2));
score_no_2.setText(record.getRankScore(2));
no_3.setText(record.getRank(3));
score_no_3.setText(record.getRankScore(3));
no_4.setText(record.getRank(4));
score_no_4.setText(record.getRankScore(4));
no_5.setText(record.getRank(5));
score_no_5.setText(record.getRankScore(5));
}
no_1~no_5是Label，record是rank类别的物件
後面的record.getRank()的code如下(定义在Rank class内)
public String getRank(int num){
if(num == 1)
filename = "no_1";
else if(num == 2)
filename = "no_2";
else if(num == 3)
filename = "no_3";
else if(num == 4)
filename = "no_4";
else if(num == 5)
filename = "no_5";
try {
//开档，读取文字
FileReader fis = new FileReader("text\\" + filename + ".txt");
text = "";
for(int c = fis.read(); c != -1; c = fis.read()){
text += (char)c;
}
//关档
fis.close();
this.rank = text;
System.out.println(text);
//回传文字
return rank;
} catch (FileNotFoundException ex) {
ex.printStackTrace();
} catch (IOException ex) {
ex.printStackTrace();
}
return "";
}
使用的IDE是netbeans 6.5.1
不知道是我观念有错还是怎样@ @a，de了挺久的bug，但显示出来一直是空白的
如果有人知道是怎麽一回事的话，请不吝指教
本版首PO，请鞭小力一点> <
感谢
--
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◆ From: 59.113.10.125
※ 编辑: jerrychai25 来自: 59.113.10.125 (04/19 15:36)
1F：推 jtmh:GUI.jButtonRankActionPerformed(GUI.java:624) -> 看看第 04/19 15:44
2F：→ jtmh:624 行哪个变数没初始值是 null 的。 不等推文红绿灯了 04/19 15:47
3F：→ jerrychai25:哦哦@@ 04/19 15:49
4F：→ jerrychai25:可是我每个变数都有初始值啦0.0 04/19 15:59
5F：推 yuekun:NullPointerException有时候你给的index比阵列还大也会出现 04/19 16:32
6F：推 Goodwater:最讨厌看到NullPointerException = = 04/19 17:21
7F：→ jerrychai25:可是我没用阵列啊=口=，我在想该不会是我的reader写错 04/19 17:23
8F：推 qrtt1:你是纯用眼睛debug 还是加用 ide 的 debug mode @@? 04/19 17:26
9F：推 TonyQ:null pointer 很单纯就是自己没有处理好...是自己要检讨 04/19 19:29
10F：→ jerrychai25:我什麽code都没改..........离开一个小时回来可以动了 04/19 20:25
11F：推 szss8765:通常错误就看第一行,有时候改第一行可以少很多错误讯息 04/20 02:10