正则表达式应用的4中情况

/**
     * 查找是否包含指定的字符串
     * @return
     */
    public static boolean  find(){
        String str = "abc efg ABC";
        String regex = "a|f";//e或者f
        Pattern pattern = Pattern.compile(regex);
        Matcher mat = pattern.matcher(str);
        boolean flag = mat.find();
       
        //仅使用一次的正则表达式可以如下使用
    //  boolean f = Pattern.matches( "a|f","abc efg ABC");
       return flag;
    }
   
    /**
     * 提取字符串
     * @return
     */
    public static String get()
    {
        String regEx=".+/(.+)$";

        String str="x/tt.x";

        Pattern p=Pattern.compile(regEx);

        Matcher m=p.matcher(str);

        boolean rs=m.find();
        System.out.println(rs);
        String s = null;
        for(int i=1;i<=m.groupCount();i++){
           
            s = m.group(i);
        }
        return s;
    }
   
    /**
     * 分隔字符串
     */
    public static void split(){
        String regex = ",";
        String str = "a,g,c,d";
        Pattern p = Pattern.compile(regex);
        String[] ary = p.split(str);

        for (int i = 0; i < ary.length; i++) {
           System.out.println(ary[i]);
        }
     
    }
   
    /**
     * 替换或删除
     * @return
     */
    public static String replace(){
        String regex="a+";
        String str = "asdfadfasd";
        Pattern p = Pattern.compile(regex);
        Matcher mat = p.matcher(str);
        String s = mat.replaceAll("A");
       // String s = mat.replaceAll("");//替换成空的话，删除匹配的值
        return s;
    }