java 缓冲阅读器和扫描器
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buffered reader and scanner
提问by dawnoflife
I want to know what's wrong with this. it gives me a constructor error (java.io.InputSream)
我想知道这有什么问题。它给了我一个构造函数错误（java.io.InputSream）
BufferedReader br = new BufferedReader(System.in);
String filename = br.readLine();
回答by corsiKa
A BufferedReader is a decorator that decorates another reader. An InputStream isn't a a reader. You need an InputStreamReader first.
BufferedReader 是装饰另一个阅读器的装饰器。InputStream 不是阅读器。您首先需要一个 InputStreamReader。
BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
In response to your comment, here's the javadoc for readline:
为了回应您的评论，这里是 readline 的 javadoc：
readLine
读行
public String readLine()
throws IOException
Read a line of text. A line is considered to be terminated by any one of a line feed ('\n'), a carriage return ('\r'), or a carriage return followed immediately by a linefeed.
Returns:
A String containing the contents of the line, not including any line-termination characters, or null if the end of the stream has been reached
Throws:
IOException - If an I/O error occurs
To handle this appropriately you need to either place the method call in a try/catch block or declare that it can be thrown.
要适当地处理这个问题，您需要将方法调用放在 try/catch 块中或声明它可以被抛出。
An example of using a try/catch block:
使用 try/catch 块的示例：
BufferedReader br = new BufferedReader (new InputStreamReader(System.in));
try{
String filename = br.readLine();
} catch (IOException ioe) {
System.out.println("IO error");
System.exit(1);
}
An example of declaring that the exception may be thrown:
声明可能抛出异常的示例：
void someMethod() throws IOException {
BufferedReader br = new BufferedReader (new InputStreamReader(System.in));
String filename = br.readLine();
}
回答by Feisty Mango
For what you are trying to do, I would recommend utilizing the Java.util.Scanner class. Pretty easy for reading input from the console.
对于您想要做的事情，我建议您使用 Java.util.Scanner 类。从控制台读取输入非常容易。
import java.util.Scanner;
public void MyMethod()
{
Scanner scan = new Scanner(System.in);
String str = scan.next();
int intVal = scan.nextInt();
double dblVal = scan.nextDouble();
// you get the idea
}
Here is the documentation link http://download.oracle.com/javase/1.5.0/docs/api/java/util/Scanner.html
这是文档链接http://download.oracle.com/javase/1.5.0/docs/api/java/util/Scanner.html
