我有这个代码，在读完前三行输入后，它会终止程序，不会让我进入下一行。这是代码：
import java.util.Arrays;
import java.util.Scanner;
public class cycle {
public static void main(String[] arg)
{
System.out.println("Put in numbers");
Scanner in=new Scanner(System.in);
int indicator=Integer.parseInt(in.nextLine());
if(indicator==1)
{
mission1();
}
else if(indicator==2)
{
mission2();
}
in.close();
}
static void mission1()
{
Scanner miss1=new Scanner(System.in);
int citizens=Integer.valueOf(miss1.nextLine());
String lines=miss1.nextLine();
lines=lines.replaceAll("\\s", "");
int length=lines.length();
String lines2=miss1.nextLine();
lines2=lines.replaceAll("\\s", "");
int length2=lines.length();
while(citizens!=length||citizens!=length2)
{
System.out.println("Citizens number do not match, try again" );
miss1=new Scanner(System.in);
citizens=Integer.valueOf(miss1.nextLine());
lines=miss1.nextLine();
lines=lines.replaceAll("\\s", "");
length=lines.length();
lines2=miss1.nextLine();
lines2=lines.replaceAll("\\s", "");
length2=lines.length();
miss1.close();
if(citizens!=length||citizens!=length2)
{
throw new IndexOutOfBoundsException("Numebr of citizens do not match. Please enter numbers again");
}
else if(citizens==length&&citizens==length2)
{
String[] strs=lines.trim().split("\\s");
length=lines.length();
int[] dspeed = new int[length];
for(int i=0; i<length;i++)
{
dspeed[i]=Integer.parseInt(strs[i]);
}
String[] strs2=lines2.trim().split("\\s+");
int[] pspeed = new int[length2];
for(int i=0; i<length2;i++)
{
pspeed[i]=Integer.parseInt(strs2[i]);
}
Arrays.sort(dspeed);
break;
}
}
}
static void mission2()
{
}
}
例如，输入如下：
Put in numbers
1
3
1 3 5
1 3 5
它只会终止程序并且没关系，但输入如下：
Put in numbers
1
3
1 3
1 3
Citizens number does not match, try again
1
3
1 3 5
程序将在我无法进入第四行之前终止。
作为我放入的测试
for(int n=0;n<length;n+=1)
{
System.out.println(dspeed[n]);
}
在Arrays.sort（dspeed [n]）和break之间，结果是这样的
Put in numbers
1
3
1 3
1 3
Citizens number do not match, try again
1
3
1 3 5
3
没有任何意义，因为它给了我3的输出而不让我进入第二行。所以它就像是跳过代码的一部分。为什么会发生这种情况？如何解决这个问题？
编辑：对于mission1，它假设得到一个数字（比方说x），然后从下一行得到x个不同的数字。然后，它应该将这些数字放在一个数组中并对它们进行排序
答案 0 :(得分：0)
在写我的答案时，我意识到你的错误的实际原因是什么;看看这段代码：
lines=miss1.nextLine();
lines=lines.replaceAll("\\s", "");
length=lines.length();
lines2=miss1.nextLine();
/*Should be lines2!*/
lines2=lines.replaceAll("\\s", "");
/*Should be lines2!*/
length2=lines.length();
您正在使用lines表示所有变量。将lines和lines2变量的lines2 = ...更改为length2可修复您发布的问题。我也换了
if (citizens != length || citizens != length2) {
/*If you decide to keep this, it should not be a "IndexOutOfBoundsException
(since no index was out of bounds) but should perhaps be a "IllegalArgumentException"
since you supplied it illegal arguments.*/
throw new IndexOutOfBoundsException("Numebr of citizens do not match. Please enter numbers again");
} else if (citizens == length && citizens == length2) { ... }
with
if (citizens == length && citizens == length2) { ... }
否则，如果连续两次输入无效输入，则会导致程序崩溃。
这是整个班级代码。这似乎已经解决了你的错误，我还重新构建了一些代码并添加了注释，解释了我编辑的内容以及我重构它的原因。如果有任何不清楚或者实际上没有解决您的错误，请发表评论。请注意，为清楚起见，这些答案中没有输入。
public class Cycle {
/* Important! We can re-use the same scanner for all inputs. */
final Scanner in;
public Cycle() {
in = new Scanner(System.in);
run();
in.close();
}
private void run() {
System.out.println("Input mission number.");
final int indicator = Integer.parseInt(in.nextLine());
if (indicator == 1) {
mission1();
} else if (indicator == 2) {
// etc
}
}
private void mission1() {
while (true) {
System.out.println("Input number of citizens.");
final int citizens = Integer.valueOf(in.nextLine());
/* We don't edit these two first inputs just yet since we
* have to use the un-edited inputs later in our if-else
* statement. */
System.out.println("Input first number(s).");
final String inputOne = in.nextLine();
System.out.println("Input second number(s).");
final String inputTwo = in.nextLine();
final String lines = inputOne.replaceAll("\\s", "");
final int length = lines.length();
final String lines2 = inputTwo.replaceAll("\\s", "");
final int length2 = lines2.length();
if (citizens != length || citizens != length2) {
/* If the number of citizens doesn't match it just
* continues the while-loop and does it all over
* again. */
System.out.println("Citizens number do not match, try again");
} else {
/* Here we use the unedited inputs from before - which
* is why we didn't edit them. */
final int[] dspeed = createArrayFromInput(inputOne);
final int[] pspeed = createArrayFromInput(inputTwo);
break;
}
}
}
/* We shouldn't have duplicated code - use a method instead. */
private int[] createArrayFromInput(final String input) {
final String[] strs = input.trim().split("\\s+");
/* The arrays should be the same size so use 'strs.length' as
* length */
final int[] speed = new int[strs.length];
for (int i = 0; i < strs.length; i++) {
speed[i] = Integer.parseInt(strs[i]);
}
Arrays.sort(speed);
return speed;
}
public static void main(final String[] arg) {
/*We should use a class instance instead of static methods and variables.*/
new Cycle();
}
}