Java 如何在while循环中只打印一次语句?
正如您所看到的,无论文本文件中有多少行代码,最后一行代码都将被打印多次。有没有办法只打印一次?Java 如何在while循环中只打印一次语句?,java,while-loop,Java,While Loop,正如您所看到的,无论文本文件中有多少行代码,最后一行代码都将被打印多次。有没有办法只打印一次? 提前感谢。如果要打印此语句一次并退出循环 你可以加上 打破在if语句之后 { System.out.println("Enter input file name:"); Scanner keyboard = new Scanner(System.in); String fileName = keyboard.nextLine(); File read = new File(file
提前感谢。如果要打印此语句一次并退出循环 你可以加上 打破在if语句之后
{
System.out.println("Enter input file name:");
Scanner keyboard = new Scanner(System.in);
String fileName = keyboard.nextLine();
File read = new File(fileName);
Scanner inputFile = new Scanner(read);
if(read.length() == 0)
{
System.out.println("empty file");
return;
}
inputFile.useDelimiter(":");
String name, code, line, distance;
System.out.println("Enter station name");
String stationName = keyboard.nextLine();
while(inputFile.hasNextLine())
{
name = inputFile.next();
code = inputFile.next();
line = inputFile.next();
distance = inputFile.nextLine();
if(stationName.equalsIgnoreCase(name))
{
System.out.println("Station code: " + code + " name: " + name);
System.out.println("distance " + distance + " kms, is on the " + line + " line");
}
else if(!stationName.equalsIgnoreCase(name))
{
System.out.println("No information was found for station " + stationName);
}
我猜您要做的是在读取整个文件后才显示此错误消息。您可以使用一个布尔变量
stationFound
初始化为false
,并在找到匹配的电台时将其设置为true
。
在while循环之后,您可以检查stationFound
是否为真,如果不是,则显示错误消息
请注意,一旦找到匹配的电台,也可以使用中断
,以避免在不需要时读取整个文件
下面是它在代码中的外观:
else if(!stationName.equalsIgnoreCase(name))
{
System.out.println("No information was found for station " + stationName);
break;
}
你有没有考虑过休息一下
boolean stationFound = false;
while(inputFile.hasNextLine())
{
// ...
if(stationName.equalsIgnoreCase(name))
{
System.out.println("Station code: " + code + " name: " + name);
System.out.println("distance " + distance + " kms, is on the " + line + " line");
stationFound = true;
break;
}
}
if(!stationFound)
{
System.out.println("No information was found for station " + stationName);
}
您可以声明一个布尔变量hasprint=false,然后make,然后add&!HASPRINT到else if语句,并在内部逻辑中将HASPRINT设置为true为System.out.println编写一个返回true的包装器方法。将其称为“print”。打印后中断方法。注意:在本例中,您不需要else-if条件。否则就足够了,因为您只需输入第二个块,如果stationName不等于nameOnly,那么这个答案似乎能够理解他在尝试做什么
else if(!stationName.equalsIgnoreCase(name))
{
System.out.println("No information was found for station " + stationName);
break;
}