Java正则表达式入门学习

package org.luosijin.test; 
 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
public class Regex { 
 public static void main(String[] args) { 
  Pattern pattern = Pattern.compile("b*g"); 
  Matcher matcher = pattern.matcher("bbg"); 
  System.out.println(matcher.matches()); 
  System.out.println(pattern.matches("b*g","bbg")); 
  //验证邮政编码 
  System.out.println(pattern.matches("[0-9]{6}","200038")); 
  System.out.println(pattern.matches("//d{6}","200038")); 
  //验证电话号码 
  System.out.println(pattern.matches("[0-9]{3,4}//-?[0-9]+","02178989799")); 
  getDate("Nov 10,2009"); 
  charReplace(); 
  //验证身份证:判断一个字符串是不是身份证号码，即是否是15或18位数字。 
  System.out.println(pattern.matches("^//d{15}|//d{18}$","123456789009876")); 
  getString("D:/dir1/test.txt"); 
  getChinese("welcome to china,江西奉新,welcome,你!"); 
  validateEmail("luosijin123@163.com"); 
 } 
 /** 
  * 日期提取:提取出月份来 
  */ 
 public static void getDate(String str){ 
  String regEx="([a-zA-Z]+)|//s+[0-9]{1,2},//s*[0-9]{4}"; 
  Pattern pattern = Pattern.compile(regEx); 
  Matcher matcher = pattern.matcher(str); 
  if(!matcher.find()){ 
   System.out.println("日期格式错误!"); 
   return; 
  } 
  System.out.println(matcher.group(1)); //分组的索引值是从1开始的，所以取第一个分组的方法是m.group(1)而不是m.group(0)。 
 } 
 /** 
  * 字符替换:本实例为将一个字符串中所有包含一个或多个连续的“a”的地方都替换成“A”。 
  */ 
 public static void charReplace(){ 
  String regex = "a+"; 
  Pattern pattern = Pattern.compile(regex); 
  Matcher matcher = pattern.matcher("okaaaa LetmeAseeaaa aa booa"); 
  String s = matcher.replaceAll("A"); 
  System.out.println(s); 
 } 
 /** 
  * 字符串提取 
  */ 
 public static void getString(String str){ 
  String regex = ".+/(.+)$"; 
  Pattern pattern = Pattern.compile(regex); 
  Matcher matcher = pattern.matcher(str); 
  if(!matcher.find()){ 
   System.out.println("文件路径格式不正确！"); 
   return; 
  } 
  System.out.println(matcher.group(1)); 
 } 
 /** 
  * 中文提取 
  * @param str 
  * @author 罗嗣金 
  * @date 2009-11-10 上午12:27:17 
  */ 
 public static void getChinese(String str){ 
  String regex = "[//u4E00-//u9FFF]+";//[//u4E00-//u9FFF]为汉字 
  Pattern pattern = Pattern.compile(regex); 
  Matcher matcher = pattern.matcher(str); 
  StringBuffer sb = new StringBuffer(); 
  while(matcher.find()){ 
   sb.append(matcher.group()); 
  } 
  System.out.println(sb); 
 } 
  public static void validateEmail(String email){ 
  String regex = "[0-9a-zA-Z]+@[0-9a-zA-Z]+//.[0-9a-zA-Z]+"; 
  Pattern pattern = Pattern.compile(regex); 
  Matcher matcher = pattern.matcher(email); 
  if(matcher.matches()){ 
   System.out.println("这是合法的Email"); 
  }else{ 
   System.out.println("这是非法的Email"); 
  } 
 } 
}