判断用户提交的是否为IP地址，看似简单，貌似就是字符串什么的对比，却也用了不少技术
我是用struts的validate判断的，只把validate方法粘贴上
public ActionErrors validate(ActionMapping mapping,
HttpServletRequest request,HttpServletResponse response) {
ActionErrors errors = new ActionErrors() ;
//IP
if(kk_BlacklistVehicle_UserEnrol_IP==null||kk_BlacklistVehicle_UserEnrol_IP.equals(""))
{
errors.add("errorKK_BlacklistVehicle_UserEnrol",new ActionMessage("kk_BlacklistVehicle_UserEnrol_IP.null")) ;
}
else
{
if(kk_BlacklistVehicle_UserEnrol_IP.length()>15)
{
errors.add("errorKK_BlacklistVehicle_UserEnrol",new ActionMessage("kk_BlacklistVehicle_UserEnrol_IP.leng")) ;
}
else
{
StringTokenizer st = new StringTokenizer(kk_BlacklistVehicle_UserEnrol_IP,".",false);//去掉IP地址中的'.'
System.out.println( "Token Total: " + st.countTokens() );
boolean b = true;
while( st.hasMoreElements() )
{
for (int i = st.nextToken().length();--i>=0;)
{
//判断去掉'.'后其他字符是否都是数字
if (!(kk_BlacklistVehicle_UserEnrol_IP.charAt(i) >= 48 && kk_BlacklistVehicle_UserEnrol_IP.charAt(i) <= 57))
{
System.out.println("您输入的IP中除了数字和.还包括了其他字符!请重新输入.");
errors.add("errorKK_BlacklistVehicle_UserEnrol",new ActionMessage("kk_BlacklistVehicle_UserEnrol_IP.ZiFu")) ;
b = false;
break;
}
else
{
b = true;
}
}
}
boolean isIP = true;
if(b)
{
//去掉'.'后其他字符是否都是数字进入到此if
int count = 0;
String temp = kk_BlacklistVehicle_UserEnrol_IP;
if(temp.charAt(0) == '.' || temp.charAt(temp.length()-1) == '.' || temp.length()>15)
{
//判断第一位和最后一位是不是'.'，是的话isIp设置为false
isIP = false;
}
//这个for循环判断'.'是不是3个，如果不是3个，设置isIP为fasle
for(int i=0;i<temp.length();i++)
{
if(temp.charAt(i) == '.')
{
count++;
}
}
if(count != 3)
{
isIP = false;
}
}
if(!isIP)
{
//isIP为false，提示错误信息
errors.add("errorKK_BlacklistVehicle_UserEnrol",new ActionMessage("kk_BlacklistVehicle_UserEnrol_IP.GeShi")) ;
}
}
}
return errors;
} PS：kk_BlacklistVehicle_UserEnrol_IP为用户提交上来的property
其他的我都加了详细的注释
粘贴个经我修改过的判断IP的带有main方法的类
package test;
import java.io.BufferedReader;
import java.io.IOException;
import java.io.InputStreamReader;
import java.util.StringTokenizer;
public class ValidIP
{
public static boolean isNumeric(String str)
{
StringTokenizer st = new StringTokenizer(str,".",false);
System.out.println( "Token Total: " + st.countTokens() );
boolean b = true;
while( st.hasMoreElements() )
{
for (int i = st.nextToken().length();--i>=0;)
{
if (!(str.charAt(i) >= 48 && str.charAt(i) <= 57))
{
System.out.println("您输入的不是纯数字!请重新输入.");
b = false;
continue;
}
else
{
b = true;
}
}
}
return b;
}
public boolean validIP(String ip)
{
int count = 0;
boolean isIP = true;
String temp = ip;
if(temp.charAt(0) == '.' || temp.charAt(temp.length()-1) == '.' || temp.length()>15)
{
isIP = false;
}
for(int i=0;i<temp.length();i++)
{
if(temp.charAt(i) == '.')
{
count++;
}
}
if(count != 3)
{
isIP = false;
}
return isIP;
}
public static void main(String[] args) throws IOException
{
// System.out.print("Input IP Address:");
// BufferedReader br = new BufferedReader(new InputStreamReader(System.in));
// String tempbr = new String(br.readLine());
//此处3行注释打开是由自己输入字符，我为了方便就把这里注释掉直接自己传字符串了
ValidIP isip = new ValidIP();
boolean a = isip.isNumeric("111.111.1.1.21");//判断传进去的字符串是否除了'.'就是数字
System.out.println(a);
if(a)//是的话进入这个if
{
boolean bl = isip.validIP("111.111.1.1.21");//判断这个ip地址的规格对不对
System.out.println(bl);//对打印true错false
}
}
}下面再粘个用swing包的判断IP的类，有main方法，但我未修改，你自己修改一下吧，好象是这个输入英文字母也判断为正确的IP地址，用的话参考我上边的例子，用StringTokenizer控制一下，如果你有更好的方法，请留言，也让我学习学习
package test;
import javax.swing.JOptionPane;
public class IDTests
{
public static void main(String as[])
{
String id = new String ();
id=JOptionPane.showInputDialog(null,"Please input ID:");
int add=id.length();
String ad = new String();
ad=String.valueOf(add);
String test = new String();
boolean b1=false;
boolean b2=false;
boolean b3=false;
boolean b4=false;
int found=1;
if(id.charAt(0) == '.' || id.charAt(id.length()-1) == '.'|| add >15)
{
JOptionPane.showMessageDialog(null,"IPAddress is error");
}
else
{
for(int i=0;i<add;i++ )
{
if(String.valueOf(id.charAt(i)).equals("."))
{
//JOptionPane.showMessageDialog(null,String.valueOf(i));
int testadd = Integer.parseInt(test);
if(found==1)
{
if(testadd > 0 && testadd< 255)
{
b1=true;
}
}
if(found==2)
{
if(testadd >=0 && testadd< 255)
{
b2=true;
}
}
if(found==3)
{
if(testadd >=0 && testadd < 255)
{
b3=true;
}
}
test=new String();
found++;
}
else
{
test=test+String.valueOf(id.charAt(i));
if(i==(add-1))
{
int testadd = Integer.parseInt(test);
if(testadd >=0 && testadd< 255)
{
b4=true;
}
}
}
}
}
//JOptionPane.showMessageDialog(null,"b1+"+String.valueOf(b1));
//JOptionPane.showMessageDialog(null,"b2"+String.valueOf(b2));
//JOptionPane.showMessageDialog(null,"b3"+String.valueOf(b3));
//JOptionPane.showMessageDialog(null,"b4"+String.valueOf(b4));
if(b1&&b2&&b3&&b4)
{
JOptionPane.showMessageDialog(null,"IPAddress is exactly!");
}
else
{
JOptionPane.showMessageDialog(null,"IPAddress is error");
}
}
}
