一文教你读懂Java中的正则表达式

//匹配 
  /* 
   * 1、对qq号进行校验 
   * 要求：5~15 0不能开头，只能是数字 
   */ 
  //非正则写法 
  public static void checkQQ1(String qqStr){ 
    int len = qqStr.length(); 
    if(len>=5 && len<=15){ 
      if(qqStr.indexOf(0)!='0'){ 
        Long l = Long.parseLong(qqStr); 
        System.out.println("qq为：" + l); 
      } 
      else 
        System.out.println("不可以0开头"); 
    } 
    else 
      System.out.println(qqStr + "不合法"); 
  } 
  //正则写法 
  public static void checkQQ(String qqStr){ 
    //定义规则 
    String reg = "[1-9]\\d{4,14}"; 
    if(qqStr.matches(reg)) 
      System.out.println("qq:" + qqStr); 
    else 
      System.out.println(qqStr + "不是qq号"); 
  } 
  //匹配电话号码 
  /* 
   * 1、手机号段只有 13xxx 15xxx 18xxxx 
   * 2、座机号：010-65784236,0316-3312617,022-12465647,03123312336 
   */ 
  public static void checkTel(String telStr, String regex){     
    if(telStr.matches(regex)) 
      System.out.println(telStr); 
    else 
      System.out.println("此号码非电话号"); 
  }

public static void main(String[] args) { 
    //------匹配----- 
    //校验qq号 
     
    checkQQ1("1670123"); 
    checkQQ("167014f23"); 
    checkQQ("01654212465"); 
     
    //座机号 
    String reg1 = "0\\d{2}-?\\d{8}|0\\d{3}-?\\d{7}"; 
    System.out.println("座机号为："); 
    checkTel("010-43367456", reg1); 
    //手机号 
    String reg2 = "1[358]\\d{9}"; 
    System.out.println("手机号为："); 
    checkTel("13103030605", reg2); 
}

//切割 
  //切割带空格或点的字符串 
  public static void splitDemo(String str, String reg){ 
    String[] arr = str.split(reg); 
    System.out.println("长度为：" + arr.length); 
    for(String s : arr){ 
      System.out.println(s); 
    } 
  }

public static void main(String[] args) { 
    //----------切割---------- 
    String str1 = "zhangsan lisi wangwu  zhaoliu"; 
    String str2 = "zhangsan.lisi.wangwu.zhaoliu"; 
    System.out.println("str1的结果："); 
    splitDemo(str1, " +|\\."); 
    System.out.println("str2的结果："); 
    splitDemo(str2, " +|\\."); 
    String strsp = "erkktyqqquizzzzzo"; 
    System.out.println("按叠词切："); 
    splitDemo(strsp, "(.)\\1+"); 
}

//替换 
  public static void replaceDemo(String str, 
      String regex, String newStr){ 
    str = str.replaceAll(regex, newStr); 
    System.out.println(str); 
     
  } 

public static void main(String[] args) { 
    //----------替换---------- 
    System.out.println("--替换---"); 
    //替换数字 
    String strNum = "wer1389980000ty1234564uiod234345675f"; 
    replaceDemo(strNum, "\\d+", "*"); 
    //替换叠词 
    String strs = "erkktyqqquizzzzzo"; 
    replaceDemo(strs, "(.)\\1+", "$1"); 
  }

import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
 
public class RegexGetMathod { 
 
  public static void main(String[] args) { 
    String str = "ming tian jiu yao fang jia le ,da jia。"; 
    getSub(str, "\\b[a-z]{3}\\b"); 
 
  } 
  //获取子串 
  public static void getSub(String str, String regex){ 
    //将规则封装成对象 
    Pattern p = Pattern.compile(regex); 
    //让正则对象和要作用的字符集相关联，获取匹配器对象 
    Matcher m = p.matcher(str); 
    //boolean b = m.find()；//将规则作用到字符串上，并进行符合规则的子串查找 
    //m.group()；//用于获取匹配后结果 
    while(m.find()){ 
      System.out.print(m.group()); 
      System.out.println("-->位置为：" + m.start() + "---" + m.end()); 
    } 
     
  } 
 
}

public static void replaceStr() 
  { 
    String str = "我我...我我...我要..要要...要要...学学学....学学...编编编...编程..程.程程...程...程"; 
    /* 
    将已有字符串变成另一个字符串。使用 替换功能。 
    1,可以先将 . 去掉。 
    2，在将多个重复的内容变成单个内容。 
    */ 
     
    str = str.replaceAll("\\.+", ""); 
    System.out.println(str); 
     
    str = str.replaceAll("(.)\\1+", "$1"); 
    System.out.println(str); 
 
  }

public static void ipSort() 
  { 
    String ip = "192.68.1.254 102.49.23.013 10.10.10.10 2.2.2.2 8.109.90.30"; 
    ip = ip.replaceAll("(\\d+)", "00$1"); 
    System.out.println(ip); 
     
    ip = ip.replaceAll("0*(\\d{3})", "$1"); 
    System.out.println(ip); 
    String[] strs = ip.split(" "); 
    Arrays.sort(strs); 
    for(String str : strs){ 
      str = str.replaceAll("0*(\\d+)", "$1"); 
      System.out.println(str); 
    } 
  }

public static void checkMail() 
  { 
    String mail = "abc12@sina.com"; 
    //mail = "1@1.1"; 
     
    String reg = "[a-zA-Z_0-9]+@[a-zA-Z0-9]+(\\.[a-zA-Z]+){1,2}";//较为精确的匹配。 
    //reg = "\\w+@\\w+(\\.\\w+){1,2}";//相对不太精确的匹配。 
    //mail.indexOf("@")!=-1 
     
    System.out.println(mail.matches(reg)); 
  }

import java.io.BufferedReader; 
import java.io.IOException; 
import java.io.InputStreamReader; 
import java.net.MalformedURLException; 
import java.net.URL; 
import java.net.URLConnection; 
import java.util.regex.Matcher; 
import java.util.regex.Pattern; 
 
public class RegexTest1 { 
 
  /** 
   * @网络爬虫 
   * 
   */ 
  public static void main(String[] args) { 
    crawler("file:///C:/Documents%20and%20Settings/Administrator/%E6%A1%8C%E9%9D%A2/%E9%82%AE%E4%BB%B6.htm"); 
 
  } 
   
  //网页爬虫功能，获取指定网址的邮箱 
  public static void crawler(String urlPath){ 
    URL ul = null; 
    BufferedReader br = null; 
    //建立连接 
    try { 
      ul = new URL(urlPath); 
    } catch (MalformedURLException e) { 
      throw new RuntimeException("指定地址未找到"); 
    } 
    URLConnection conn; 
    try { 
      conn = ul.openConnection(); 
      br = new BufferedReader(new InputStreamReader(conn.getInputStream())); 
    } catch (IOException e1) { 
      throw new RuntimeException("连接失败"); 
    } 
    //匹配指定的内容 
    Pattern p = Pattern.compile("\\w+@\\w+(\\.\\w){1,2}"); 
    String line = null; 
    try { 
      while((line=br.readLine())!=null){ 
        Matcher m = p.matcher(line); 
        while(m.find()) 
          System.out.println(m.group()); 
      } 
    } catch (IOException e) { 
      throw new RuntimeException("读取数据失败"); 
    } 
  } 
 
}