我有2个字符串变量：
“ givenAccnt”是从用户获得的输入字符串
“ accntToken”是一行文本的子字符串（第一个字符串）
如果givenAccnt等于accntToken，我想返回由accntToken匹配的文本行。
此外，可能存在超过1个匹配项的情况。我想将所有匹配项保存到变量中，然后立即返回那些匹配项（行）。
下面的代码仅在最后一行返回匹配项。 （如果匹配在其他行中，它将丢失）
我似乎无法弄清楚为什么会这样。
任何帮助，将不胜感激。
givenAccnt = searchTextField.getText();//else, user is using search field to get given account
try
{
scanner = new Scanner(file); //initialize scanner on file
while(scanner.hasNextLine()) //while lines are being scanned
{
getLine = scanner.nextLine(); //gets a line
int i = getLine.indexOf(' '); //get first string-aka-accnToken
accntToken = getLine.substring(0, i);
}
if(givenAccnt.equals(accntToken)) //if match
{
collectedLines = new StringBuilder().append(getLine).toString();
psswrdLabels = new JLabel(collectedLines, JLabel.LEFT);
psswrdLabels.setAlignmentX(0);
psswrdLabels.setAlignmentY(0);
fndPwrdsCNTR += 1; //counter for number of passwords found
JOptionPane.showMessageDialog(null, psswrdLabels ,+fndPwrdsCNTR+" PASSWORD(S) FOUND!", JOptionPane.INFORMATION_MESSAGE); //shows window with matched passwords (as JLabels)
searchTextField.setText(""); //clears search field, if it was used
}else
//..nothing found
}catch (FileNotFoundException ex) {
//..problem processing file...
}
最佳答案
您不能在每一行上创建新的StringBuilder。而是在读取行之前创建它。代码：
givenAccnt = searchTextField.getText();//else, user is using search field to get given account
try
{
builder=new StringBuilder();//initialize builder to store matched lines
scanner = new Scanner(file); //initialize scanner on file
while(scanner.hasNextLine()) //while lines are being scanned
{
getLine = scanner.nextLine(); //gets a line
int i = getLine.indexOf(' '); //get first string-aka-accnToken
accntToken = getLine.substring(0, i);
}
if(givenAccnt.equals(accntToken)) //if match
{
collectedLines = builder.append(getLine).toString();
psswrdLabels = new JLabel(collectedLines, JLabel.LEFT);
psswrdLabels.setAlignmentX(0);
psswrdLabels.setAlignmentY(0);
fndPwrdsCNTR += 1; //counter for number of passwords found
JOptionPane.showMessageDialog(null, psswrdLabels ,+fndPwrdsCNTR+" PASSWORD(S) FOUND!", JOptionPane.INFORMATION_MESSAGE); //shows window with matched passwords (as JLabels)
searchTextField.setText(""); //clears search field, if it was used
}else
//..nothing found
}catch (FileNotFoundException ex) {
//..problem processing file...
}