正则表达式如何在java中使用

package test; 
/** 
 * 在String的matches()方法,split()方法中使用正则表达式. 
 * @author fhd001 
 */ 
public class RegexTest { 
 
  public static void main(String[] args) { 
 
    /* 
     * 普通字符 
     */ 
    String str1 = "abc45abc345"; 
    String[]arr1 = str1.split("abc"); 
    for (String string : arr1) { 
      System.out.print(string+"-->"); 
    } 
    System.out.println(); 
     
     
    /* 
     * 简单的转义字符 
     * 在java中转义字符时一定要用双反斜线,两个斜线转义成一个斜线, 
     * 在用这个斜线字符转义那些特殊字符. 
     */ 
    String str2 = "^$()[]{}.?+*|"; 
    boolean flag = str2.matches("//^//$//(//)//[//]//{//}//.//?//+//*//|"); 
    System.out.println(flag); 
     
     
    /* 
     * 转义字符 /Q.../E. 
     */ 
    String str3 = "^$()[]{}.?+*|99999"; 
    boolean flag2 = str3.matches("//Q^$()[]{}.?+*|//E//d{5}"); 
    System.out.println(flag2); 
     
     
    /* 
     * 字符集合 
     */ 
    String str4 = "dfddri334"; 
    boolean flag4 = str4.matches(".+"); 
    System.out.println(flag4); 
     
    String str5 = "#$%^*())%"; 
    boolean flag5 = str5.matches("//W{9}"); 
    System.out.println(flag5); 
     
    String str6 = "4gffmdkekrhhr"; 
    boolean flag6 = str6.matches("//w+"); 
    System.out.println(flag6); 
     
    String str7 = "fjfdke  eett "; 
    boolean flag7 = str7.matches("//w+//s+//w{4}//s?"); 
    System.out.println(flag7); 
     
    String str8 = "  erefff  "; 
    boolean flag8 = str8.matches("//s+//S+//s+"); 
    System.out.println(flag8); 
     
    String str9 = "456776888"; 
    boolean flag9 = str9.matches("//d+"); 
    System.out.println(flag9); 
     
     
    String str10 = "rtydfgrgwvr "; 
    boolean flag10 = str10.matches("//D+"); 
    System.out.println(flag10); 
     
     
    /* 
     * 自定义字符集合 [ ] 
     */ 
    String str11 = "fdfeetg 34566"; 
    boolean flag11 = str11.matches("[fdetg]+//s+[3-6]+"); 
    System.out.println(flag11); 
     
     
    String str12 = "rtyuie  5768"; 
    boolean flag12 = str12.matches("[^abcdf]+//s+[^1234]+"); 
    System.out.println(flag12); 
     
     
    /* 
     * 匹配次数限定符 
     */ 
     
    //贪婪模式 
    String str13 = "ytreggcv454444444333"; 
    boolean flag13 = str13.matches("//w{20}"); 
    System.out.println(flag13); 
     
    boolean flag14 = str13.matches("//w{10,21}"); 
    System.out.println(flag14); 
     
    boolean flag15 = str13.matches("//w{18,}"); 
    System.out.println(flag15); 
     
    String str14 = "4"; 
    boolean flag16 = str14.matches("//d?"); 
    System.out.println(flag16); 
     
    String str15 = "ddcvgt"; 
    boolean flag17 = str15.matches("//D+//d?"); 
    System.out.println(flag17); 
     
    String str16 = "e33tf44t44t"; 
    boolean flag18 = str16.matches("//w+//W*"); 
    System.out.println(flag18); 
     
    //勉强模式(只举一例) 
    String str17 = "34567ghjkkld"; 
    boolean flag19 = str17.matches("//d{2,7}?//w{8,11}"); 
    System.out.println(flag19); 
     
    //占有模式(只举一例) 
    String str18 = "22222ddddd"; 
    boolean flag20 = str18.matches("//d{2,5}+//w{6}"); 
    System.out.println(flag20); 
     
    /* 
     * 字符边界 
     */ 
    String str19 = "a444545rot44tm"; 
    boolean flag21 = str19.matches("^a//w+m$"); 
    System.out.println(flag21); 
     
     
    /* 
     * 选择表达式 xxx | xxx 
     */ 
    String str20 = "abc123abc"; 
    boolean flag22 = str20.matches("(abc|123){3}"); 
    System.out.println(flag22); 
     
     
    /* 
     * 分组 ( ). 
     * 以上修饰符都是针对一个字符进行修饰.如果要对一组字符进行 
     * 修饰就要用到() 
     */ 
    String str21 = "123qwe123qwe"; 
    boolean flag23 = str21.matches("(123qwe){2}"); 
    System.out.println(flag23); 
     
     
    /* 
     * []中的交集与并集 
     */ 
    String str22 = "abcdefgh2234567"; 
    boolean flag24 = str22.matches("[a-z1-9]+");    //并集 
    System.out.println(flag24); 
     
    boolean flag25 = str22.matches("[a-z1-9&&[a-h2-7]]+"); //交集 
    System.out.println(flag25); 
  } 
} 
 

-->45-->345--> 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
true 
false 
true 
true 
true 
true 
true