java 对 jTable 中的一列求和？
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Sum a Column in a jTable?
提问by BEE
I am having a problem trying to get values from a column within a jTable and sum them up. This is the code I have so far:
我在尝试从 jTable 中的列中获取值并对它们求和时遇到问题。这是我到目前为止的代码：
public void saveTable(){
for(int i = 0; i < jTable2.getRowCount(); i++){
int total = 0;
int Amount = (int) jTable2.getValueAt(i, 5);
total = Amount+total;
System.out.println(total);
}
}
However I keep getting ClassCastException Errors specifically:
但是我不断收到 ClassCastException 错误：
Exception in thread "AWT-EventQueue-0" java.lang.ClassCastException: java.lang.String cannot be cast to java.lang.Integer
at my.rcsv1.accounting.DraftInvoice.saveTable(DraftInvoice.java:851)
Which is referring to the line of code:
这是指代码行：
int Amount = (int) jTable2.getValueAt(i, 5);
What do I need to do in order to get this to work?
我需要做什么才能让它发挥作用？
Thank you!
谢谢！
采纳答案by Daniel Kec
int Amount = Integer.parseInt(jTable2.getValueAt(i, 5)+"");
Will do the thing
会做事
回答by Liam de Haas
You are casting to a primitive data type, you should be parsing.
您正在转换为原始数据类型，您应该进行解析。
Try this:
试试这个：
int amount = Integer.parseInt(jTable2.getValueAt(i, 5));
int amount = Integer.parseInt(jTable2.getValueAt(i, 5));
Also you shouldn't start variable names with a capital ie int Amountshould be int amount
另外你不应该用大写的变量名开始，即int Amount应该是int amount
回答by Joop Eggen
The exception says you stored a String in that column.
异常表示您在该列中存储了一个字符串。
You might do in better style by using the data model, jTable.getModel(). But this is it:
通过使用数据模型，您可能会做得更好jTable.getModel()。但就是这样：
int total = 0;
for (int i = 0; i < jTable2.getRowCount(); i++){
int amount = Integer.parseInt((String) jTable2.getValueAt(i, 5));
total += amount;
}
System.out.println(total);
