JAVA正则表达式工具类

package com.common.util;

import java.text.DecimalFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.regex.Matcher;
import java.util.regex.Pattern;

import javax.servlet.http.HttpServletRequest;

public class CheckData {
 public CheckData()
 {
 }

 
 public static String checkString(String start)
 {
     String end = null;
     if(start == null)
         return "";
     int length = start.length();
     int sub = start.indexOf("'");
     if(sub == -1)
         end = start;
     else
     if(length == sub)
         end = (new StringBuilder(String.valueOf(start))).append("'").toString();
     else
         end = (new StringBuilder(String.valueOf(start.substring(0, sub + 1)))).append("'").append(checkString(start.substring(sub + 1, length))).toString();
     return end;
 }
 
 /***
  * 判断是否为中文
  * @param str
  * @return
  */
 public static boolean isCn(String str)
 {
  
  if(str==null || str.equals("")){
   return false;
  }
  Pattern pattern = Pattern.compile("^[\u4e00-\u9fa5]+$");
  Matcher isNum = pattern.matcher(str);
  if( !isNum.matches() )
  {
   return false;
  
  }
  return true;
 }
 
 /***
  * 判断是否为数字
  * @param str
  * @return
  */
 public static boolean isNumer(String str)
 {
  if(str==null || str.equals("")){
   return false;
  }
  Pattern pattern = Pattern.compile("[0-9]*");
  Matcher isNum = pattern.matcher(str);
  if( !isNum.matches() )
  {
  return false;
  }
  return true;
 }
 /***
  * 判断是否为字母
  * @param str
  * @return
  */
 public static boolean isLetters(String str)
 {
  if(str==null || str.equals("")){
   return false;
  }
  Pattern pattern = Pattern.compile("[a-zA-Z]+");
  Matcher isNum = pattern.matcher(str);
  if( !isNum.matches() )
  {
  return false;
  }
  return true;
 }

 /******************时间转换********************/
 public String getDate(){
  SimpleDateFormat df = new SimpleDateFormat("yyyyMMddhhmmss");//设置日期格式
     String date=df.format(new Date());// new Date()为获取当前系统时间
     return date;
 }
 public Date getDate(String reqDate){
  try {
  SimpleDateFormat df = new SimpleDateFormat("yyyyMMddhhmmss");
     Date date= df.parse(reqDate);
  return date;
  } catch (ParseException e) {
   // TODO Auto-generated catch block
   e.printStackTrace();
   return null;
  }
 }
 
 /******************数据类型转换********************/
 public static Long getLong(String str){
  if(str!=null && !str.equals("")){
   return Long.parseLong(str);
  }else{
   return null;
  }
 }
 public static Integer getInteger(String str){
  if(str!=null && !str.equals("")){
   return Integer.parseInt(str);
  }else{
   return null;
  }
 }
 public static String getDouble(Double dob){
     DecimalFormat df=new DecimalFormat("0.00");
     return df.format(dob);
 }
 /**
  * 获取客户端IP
  * @param request
  * @return
  */
 public static String getIpAddr(HttpServletRequest request) {
        String ip = request.getHeader("x-forwarded-for");
        if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("Proxy-Client-IP");
        }
        if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getHeader("WL-Proxy-Client-IP");
        }
        if(ip == null || ip.length() == 0 || "unknown".equalsIgnoreCase(ip)) {
            ip = request.getRemoteAddr();
        }
        return ip;
    }
 public static String utf8Togb2312(String str){
       StringBuffer sb = new StringBuffer();
       for(int i=0; i<str.length(); i++) {
           char c = str.charAt(i);
           switch (c) {
              case '+':
                  sb.append(' ');
              break;
              case '%':
                  try {
                       sb.append((char)Integer.parseInt(
                       str.substring(i+1,i+3),16));
                  }
                  catch (NumberFormatException e) {
                      throw new IllegalArgumentException();
                 }
                 i += 2;
                 break;
              default:
                 sb.append(c);
                 break;
            }
       }
       // Undo conversion to external encoding
       String result = sb.toString();
       String res=null;
       try{
           byte[] inputBytes = result.getBytes("8859_1");
           res= new String(inputBytes,"UTF-8");
       }
       catch(Exception e){}
       return res;
 }

}