不知道什么原因？？(100分)

夜

夜游神宾

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-09-28

• #1

public class a
{
public static void main(String[] args)
{
char a;
System.out.println("Please Into a Number 1-3");
a = (char)System.in.read();
switch(a)
{
case '1':
System.out.println("your into Number is 1");
break;
case '2':
System.out.println("your into Number is 2");
break;
case '3':
System.out.println("your into Number is 2");
break;
default:
System.out.println("your into Number is "+a);
break;
}
}
}
javac a.java
错误提示如下：

a.java:8: unreported exception java.io.IOException;
must be caught or declared to be thrown
a = (char)System.in.read();
^
1 error
这是为什么,我没看出错误？？？
请各位大侠多多指教我（刚刚开始学java两天）。

 

H

hanyongjian

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-09-28

• #2

好象是因为System.in.read()方法中定义了可能的抛出异常，你必需对此可能发生的
异常进行处理。用Try..except语句。
不要问我更多的东西，我没有学过Java。

 

小

小猪

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-09-28

• #3

hanyongjian是对的。
system.in.read方法申明抛出io异常，你应该主动捕获这个异常。
修改后的代码如下：
try{
a = (char)System.in.read();
switch(a)
{
case '1':
System.out.println("your into Number is 1");
break;
case '2':
System.out.println("your into Number is 2");
break;
case '3':
System.out.println("your into Number is 2");
break;
default:
System.out.println("your into Number is "+a);
break;
}
}catch(IOException ioexp){
System.out.println("there is a IOException occured,the detailinfo is ");
ioexp.printStack();
}

 

夜

夜游神宾

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-10

• #4

如此更改后，错误提示如下：
C:/>javac a.java
a.java:27: cannot resolve symbol
symbol : class IOException
location: class a
catch(IOException ioexp)
^
1 error
还是过不去，请指教，这到底是什么原因？

 

F

fbyang

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GUEST, unregistred user!

• 2002-10-10

• #5

听！

 

夜

夜游神宾

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GUEST, unregistred user!

• 2002-10-10

• #6

to fbyang ：你有什么意见吗？说来听听。

 

N

naughtboy

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-10

• #7

要import java.io.*;吧

 

夜

夜游神宾

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-11

• #8

各位可以在本机上试一试。谁能告诉我？？

 

小

小猪

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-11

• #9

import java.io.*;

 

夜

夜游神宾

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GUEST, unregistred user!

• 2002-10-15

• #10

import java.io.*;
public class a
{
public static void main(String[] args)
{
char a;
System.out.println("Please Into a Number 1-3");
a = (char)System.in.read();
switch(a)
{
case '1':
System.out.println("your into Number is 1");
break;
case '2':
System.out.println("your into Number is 2");
break;
case '3':
System.out.println("your into Number is 2");
break;
default:
System.out.println("your into Number is "+a);
break;
}
}
}
javac a.java
error hint:
C:/>javac a.java
a.java:9: unreported exception java.io.IOException;
must be caught or declared t
o be thrown
a = (char)System.in.read();
^
1 error
为什么？？？？？？？？？？？？我要疯了！！！？？？？？

 

L

libaoliang

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-15

• #11

gz

 

B

Blue_Bird

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-15

• #12

在main（） 后 加一句 throws IOException 就可以通过了
import java.io.*;
public class a
{
public static void main(String[] args) throws IOException
{
char a;
System.out.println("Please Into a Number 1-3");
a = (char)System.in.read();
switch(a)
{
case '1':
System.out.println("your into Number is 1");
break;
case '2':
System.out.println("your into Number is 2");
break;
case '3':
System.out.println("your into Number is 2");
break;
default:
System.out.println("your into Number is "+a);
break;
}
}
}

 

小

小猪

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-16

• #13

兄弟，看书啊，随便找本书都有解释的，我懒得帮你了。

 

夜

夜游神宾

Unregistered / Unconfirmed

GUEST, unregistred user!

• 2002-10-16

• #14

我是初学者耶，输入输出流还没有看到呢，如果不是这样，我也不至于落魄到如此地步。
多谢各位侠中客来光临指导，以后还请多多帮助。谢谢！