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我似乎無法找到我得到NullPointerException在調用方法fillTable()時出錯。 fillTable是從按鈕中調用的,它來自textField中的String。 fillTable是爲了通過從處理程序類中檢索包含數據的Object [] []來填充JTable。NullPointerException調用fillTable時出錯()
private void fillTable(String dataType, String searchBy)
{
String[] columnName = {"module name", "Workshop %", "Lecture %", "Tutorial %", "Average %"};
if(searchBy.startsWith("@"))
{
tableModel.setDataVector(pLSHand.gIStudData(dataType, searchBy), columnName);
table.setModel(tableModel);
}
else
{
tableModel.setDataVector(pLSHand.gNStudData(dataType, searchBy), columnName);
table.setModel(tableModel);
}
table.repaint();
}
按鈕:在Handler類
public Object[][] gIStudData(String dType, String studID)
{
String rQuery = "SELECT * FROM StudAttYear WHERE studentID = '"+ studID +"'";
data = new Object[1][5];
if(dType.equalsIgnoreCase("Semester"))
{
rQuery = "SELECT * FROM StudAttSem WHERE studentID = '"+ studID +"'";
data = new Object[2][5];
}
else if(dType.equalsIgnoreCase("Year"))
{
rQuery = "SELECT * FROM StudAttYear WHERE studentID = '"+ studID +"'";
data = new Object[1][5];
}
else if(dType.equalsIgnoreCase("Week"))
{
rQuery = "SELECT * FROM StudAttWeek WHERE studentID = '"+ studID +"' AND number = '"+ weekNo +"'";
data = new Object[12][5];
}
try{
Class.forName(DRIVER_CLASS);
connection = DriverManager.getConnection(url,"agile", "adila");
statement = connection.createStatement();
results = statement.executeQuery(rQuery);
int i=0;
while(results.next())
{
data[i][0] = results.getString("module");
data[i][1] = results.getString("workshop%");
data[i][2] = results.getString("tutroial%");
data[i][3] = results.getString("lecture%");
data[i][4] = results.getString("avg%");
i++;
}
results.close();
statement.close();
connection.close();
} catch (SQLException sqlException) {
sqlException.printStackTrace();
System.exit(1);
}catch(Exception exception) {
System.err.println("An error happened");
System.exit(1);
}
return data;
}
使用其他類相同的技術,他們似乎工作
String searchBy = (String)textField.getText();
if(!searchBy.isEmpty())
{
fillTable("Year",searchBy);
}
else
{
}
方法。
NPE消息會告訴您哪些行涉及異常,並且您需要從那裏開始。如果仍然卡住,你應該告訴我們那些是哪條線。 –
是'tableModel'' null'? – durron597
另外,'pLSHand''null'? – durron597