如何读取 Java 中的格式化输入？
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How do I read formatted input in Java?
提问by Lazer
Suppose my input file contains:
假设我的输入文件包含：
3 4 5 6 7 8
9
10
I want to run a while loop and read integers, so that I will get 3,4,5,6,7,8 and 10 respectively after each iteration of the loop.
我想运行一个 while 循环并读取整数，以便在每次循环迭代后分别得到 3、4、5、6、7、8 和 10。
This is really simple to do in C/C++ but not in Java...
这在 C/C++ 中确实很简单，但在 Java 中则不然......
I tried this code:
我试过这个代码：
try {
DataInputStream out2 = new DataInputStream(new BufferedInputStream(new FileInputStream(file)));
int i=out2.read();
while(i!=-1){
System.out.println(i);
i=out2.readInt();
}
} catch (IOException ex) {
}
and what I get is:
我得到的是：
51
540287029
540418080
538982176
151599117
171511050
218762506
825232650
How do I read the integers from this filein Java?
如何在Java 中从此文件中读取整数？
回答by coobird
One can use the Scannerclass and its nextIntmethod:
Scanner s = new Scanner("3 4 5 6");
while (s.hasNext()) {
System.out.println(s.nextInt());
}
Output:
输出：
3
4
5
6
Basically by default, the Scannerobject will ignore any whitespace, and will get the next token.
基本上默认情况下，Scanner对象将忽略任何空格，并将获得下一个标记。
The Scannerclass as a constructorwhich takes an InputStreamas the source for the character stream, so one could use a FileInputStreamthat opens the source of the text.
该Scanner班作为构造这需要一个InputStream作为源字符流，所以人们可以使用FileInputStream打开的文本的来源。
Replace the Scannerinstantiation in the above example with the following:
将Scanner上面示例中的实例化替换为以下内容：
Scanner s = new Scanner(new FileInputStream(new File(filePath)));
