Java 满足条件后如何跳出循环
声明：本页面是StackOverFlow热门问题的中英对照翻译，遵循CC BY-SA 4.0协议，如果您需要使用它，必须同样遵循CC BY-SA许可，注明原文地址和作者信息，同时你必须将它归于原作者（不是我）：StackOverFlow
原文地址: http://stackoverflow.com/questions/16269589/
Warning: these are provided under cc-by-sa 4.0 license. You are free to use/share it, But you must attribute it to the original authors (not me):
StackOverFlow
How to break from a loop after the condition is met
提问by user2252310
Hi I have been trying for the past hour to break from this loop and continue since already met my condition once. My application pretty much reads a serie of lines and analyzes it and then prints the variable stated. An example of how the lines look like (the . are not included):
嗨，过去一个小时我一直在尝试打破这个循环并继续，因为已经满足我的条件一次。我的应用程序几乎读取一系列行并对其进行分析，然后打印所述变量。线条外观的示例（不包括 .）：
- 10 c = 9+3
- 20 a = c+1
- 30 print c
- 40 goto 20
- 50 end
- 10 c = 9+3
- 20 a = c+1
- 30 打印 c
- 40 转 20
- 50 结束
It does everything right, when it gets to line 40 goes to line 20 as expected, but i want it to go to line 50 since already went to line 40 once. Here is my code for this part:
它做的一切都是正确的，当它到达第 40 行时按预期转到第 20 行，但我希望它转到第 50 行，因为它已经去过第 40 行一次。这是我的这部分代码：
while(booleanValue)
{
if(aString.substring(0, 4).equals("goto"))
{
int chosenLine = Integer.parseInt(b.substring(5));
if(inTheVector.contains(chosenLine))
{
analizeCommands(inTheVector.indexOf(chosenLine));
i++;
}
else
{
System.ou.println("Line Was Not Found");
i++;
}
}
else if(aString.substring(0, 3).equals("end"))
{
System.out.println("Application Ended");
booleanValue = false;
}
}
回答by MarsAtomic
Use the breakstatement to break out of a loop completely once your condition has been met. Pol0nium's suggestion to use continuewould not be correct since that stops the current iteration of the loop only.
break一旦满足您的条件，使用该语句即可完全跳出循环。Pol0nium 的使用建议是continue不正确的，因为这只会停止循环的当前迭代。
while(foo)
{
if(baz)
{
// Do something
}
else
{
// exit condition met
break;
}
}
All this having been said, good form dictates that you want clean entry and exit points so that an observer (maybe yourself, revisiting the code at a later date) can easily follow its flow. Consider altering the boolean that controls the while loop itself.
综上所述，良好的形式表明您需要干净的入口和出口点，以便观察者（可能是您自己，稍后重新访问代码）可以轻松地遵循其流程。考虑更改控制 while 循环本身的布尔值。
while(foo)
{
if(baz)
{
// Do something
}
else
{
// Do something else
foo = false;
}
}
If, for some reason, you can't touch the boolean that controls the while loop, you need only compound the condition with a flag specifically to control your while:
如果由于某种原因，您无法触摸控制 while 循环的布尔值，则只需将条件与专门用于控制 while 的标志复合：
while(foo && bar)
{
if(baz)
{
// Do something
}
else
{
// Do something else
bar = false;
}
}
回答by Scott Heaberlin
You could keep the code using booleanValueas-is and switch to a do-while loop.
您可以booleanValue按原样保留代码并切换到 do-while 循环。
do {
// ... existing code
} while (booleanValue);
However, to answer your specific question - you can always use the java breakkeyword. The continuekeyword is more for skipping the remainder of the loop block and entering another loop iteration.
但是，要回答您的特定问题 - 您始终可以使用 javabreak关键字。该continue关键字更多地用于跳过循环块的其余部分并进入另一个循环迭代。
if you put this before your check for anything else, you would exit the loop immediately.
如果你把它放在你检查其他任何东西之前，你会立即退出循环。
if(aString.substring(0, 3).equals("end")) {
break;
}
As an additional tip, you may want to use String.contains("end")or String.endsWith("end")instead of substring(). This way if a 1 or 3 digit (or more) number is used your code will still work.
作为附加提示，您可能需要使用String.contains("end")或String.endsWith("end")而不是 substring()。这样，如果使用 1 位或 3 位（或更多）数字，您的代码仍然有效。
