Java扫描程序-两个分隔符和异常
我想读取具有以下格式的文件:Java扫描程序-两个分隔符和异常,java,java.util.scanner,delimiter,Java,Java.util.scanner,Delimiter,我想读取具有以下格式的文件: c00004;Doe John;bananas;4.0;50.0 c00003;Doe John;milk;4.0;5.0 c00001;Doe John;milk;4.0;10.0 c00001;Doe John;milk;5.0;2.0 使用此代码: Scanner in = new Scanner(Paths.get(fileName)); in.useDelimiter(";|\\s"); while(in.hasNext()) { String
c00004;Doe John;bananas;4.0;50.0
c00003;Doe John;milk;4.0;5.0
c00001;Doe John;milk;4.0;10.0
c00001;Doe John;milk;5.0;2.0
使用此代码:
Scanner in = new Scanner(Paths.get(fileName));
in.useDelimiter(";|\\s");
while(in.hasNext())
{
String customerID = in.next();
String surname = in.next();
String firstName = in.next();
String productName = in.next();
double price = in.nextDouble();
double quantity = in.nextDouble();
Purchase newPurchase = new Purchase(customerID, surname, firstName, productName, price, quantity);
}
in.close();
在读取第二行数据的中间,我得到一个输入失配异常。你知道为什么吗
编辑: 如果我在读取每个变量后输出它,则输出为:c00004 Doe John bananas 4.0 50.0
c00003 Doe John Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:864)
at java.util.Scanner.next(Scanner.java:1485)
at java.util.Scanner.nextDouble(Scanner.java:2413)
at CustomersPurchaseSortFind.readFile(CustomersPurchaseSortFind.java:31)
at Main.main(Main.java:9)
或者,只需阅读整行内容,然后使用拆分:
String nextLine=in.nextLine();
String[] splitted= nextLine.split(";|\\s");
或者,只需阅读整行内容,然后使用拆分:
String nextLine=in.nextLine();
String[] splitted= nextLine.split(";|\\s");
您的正则表达式应该是:
in.useDelimiter(";|\\s+");
由于您的数据在Windows中\r\n行末有新行,因此在第二个循环中,分隔符将包含\r字符作为元素:
int i = 1;
while(in.hasNext())
{
System.out.println("line: " + i++);
String customerID = in.next();
String surname = in.next();
String firstName = in.next();
String productName = in.next();
double price = in.nextDouble();
System.out.println("Price: " + price);
double quantity = in.nextDouble();
}
输出:
line: 1
customerID: c00004
Price: 4.0
line: 2
customerID:
Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:909)
at java.util.Scanner.next(Scanner.java:1530)
at java.util.Scanner.nextDouble(Scanner.java:2456)
at Test.main(Test.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
第二个循环实际抛出异常以解析double
我们可以看到第二个customerID为空
对于第二个循环,Price值是:milk,因此它将抛出inputmaschException for Double parse您的正则表达式应该是:
in.useDelimiter(";|\\s+");
由于您的数据在Windows中\r\n行末有新行,因此在第二个循环中,分隔符将包含\r字符作为元素:
int i = 1;
while(in.hasNext())
{
System.out.println("line: " + i++);
String customerID = in.next();
String surname = in.next();
String firstName = in.next();
String productName = in.next();
double price = in.nextDouble();
System.out.println("Price: " + price);
double quantity = in.nextDouble();
}
输出:
line: 1
customerID: c00004
Price: 4.0
line: 2
customerID:
Exception in thread "main" java.util.InputMismatchException
at java.util.Scanner.throwFor(Scanner.java:909)
at java.util.Scanner.next(Scanner.java:1530)
at java.util.Scanner.nextDouble(Scanner.java:2456)
at Test.main(Test.java:32)
at sun.reflect.NativeMethodAccessorImpl.invoke0(Native Method)
at sun.reflect.NativeMethodAccessorImpl.invoke(NativeMethodAccessorImpl.java:57)
at sun.reflect.DelegatingMethodAccessorImpl.invoke(DelegatingMethodAccessorImpl.java:43)
at java.lang.reflect.Method.invoke(Method.java:601)
at com.intellij.rt.execution.application.AppMain.main(AppMain.java:140)
第二个循环实际抛出异常以解析double
我们可以看到第二个customerID为空
对于第二个循环,价格值是:milk,因此它会抛出InputMismatchException for Double parse你能发布stacktrace吗?@JordiCastilla我已经更新了帖子。很遗憾,你在Windows上,因为你在Unix系统上不会有这个问题:P.但是你已经得到了一个解决方案的答案。你能发布你的stacktrace吗?@JordiCastilla我已经更新了帖子。很遗憾,你在Windows上,因为在Unix系统上不会出现此问题:P。但您已经得到了解决方案的答案。\\s已经包括\\n:@Tom good point mate,thx。我将删除答案的第一部分,我仍然相信阅读整行文字是最简单、最安全的方法。因此,我将该部分保留为应答的一部分,然后您只需要在中修复方法调用;P.\\s已包括\\n:@Tom good point mate,thx。我将删除答案的第一部分,我仍然相信阅读整行文字是最简单、最安全的方法。因此,我将该部分保留为应答的一部分,然后您只需要在中修复方法调用;答案是正确的,但解释不精确。请重新检查您写的内容以及失败的原因。解决方案是正确的,但解释不准确。请重新检查您所写的内容以及失败的原因。