class test{ public static void main(String[] args){ String str="1234"; int i; i=Integer.parseInt(str); System.out.println(i); } }
哎,來遲一步判斷輸入框內只能輸入數字,可以通過捕捉將字符串強制轉換成整型異常 int i try { i = Integer.parseInt(textField1.getText()); } catch(Exception err) { System.out.println("input is not number"); return ; }
public static void main(String[] args){
String str="1234";
int i;
i=Integer.parseInt(str);
System.out.println(i);
}
}
int i
try
{
i = Integer.parseInt(textField1.getText());
}
catch(Exception err)
{
System.out.println("input is not number");
return ;
}
String str="12345";
int a=str.valueOf();
<script language="JavaScript">
function isValid(form)
{
var flag=false;
var zw=form.zw.value;
for(var i=0;i<zw.length;i++)
{
if((zw.substring(i,i+1)>="0")&&(zw.substring(i,i+1)<="9))
{
flag=true;
}
else {
alert("输入的数字中有非法字符");
flag=false;
break;
}
}
return flag;
}
</script>
<body>
<form action="test4.jsp" method="post" onSubmit="return isValid(this);">
输入数字<input type=text name=zw>
<input type=submit value="submit">
</form>
public int StringToInt(String aa)
{
int i = Integer.parseInt(aa);
return i;
}
String str = "123";
int i = new Integer(str).intValue();
会抛出 Exception