随记

多尝试后再问人。

个人常用正则收集，有些的自己写的，有些的搬运的

前期提要

• 正则语法参考
• 在线正则校验

匹配时间 HH:mm:ss

"([01][0-9]|2[0-3]):[0-5][0-9]:[0-5][0-9]"

中文

[\\w\\u4E00-\\u9FA5\\uF900-\\uFA2D]

贪婪模式阻止

(.*?)

不创建组

(?:xxxx)

小写转大写

# 匹配字符串：
(.*),(.*)
# 替换正则
DICT_\U$2\E = "$2";

例如：用户性别,sys_user_sex
匹配正则：(.*),(.*)，替换正则：DICT_\U$2\E = "$2";
最终替换效果为：DICT_SYS_USER_SEX = "sys_user_sex";

数字

有无符号+整数+小数

[+-]?(^0|[1-9]\\d*)(\\.\\d+)?

测试程序如下

@Test
public void test22(){
    String regex = "[+-]?(^0|[1-9]\\d*)(\\.\\d+)?";
    System.out.printf("0 %s\n","0".matches(regex));//0
    System.out.printf("10 %s\n","10".matches(regex));//整数
    System.out.printf("+10 %s\n","+10".matches(regex));//正整数
    System.out.printf("-10 %s\n","-10".matches(regex));//负整数
    System.out.printf("10.23 %s\n","10.23".matches(regex));//小数
    System.out.printf("0.23 %s\n","0.23".matches(regex));//小数
    System.out.printf("+10.23 %s\n","+10.23".matches(regex));//正小数
    System.out.printf("-10.23 %s\n","-10.23".matches(regex));//负小数
    //想要限制小数精度，直接把小数部分的\d+改为\d{精度}即可，例如限制两位小数精度则为"[+-]?(0|[1-9]\\d*)(\\.\\d{2})?"
    System.out.println("异常数字验证=============================================");
    System.out.printf("000 %s\n","000".matches(regex));//000
    System.out.printf("00.1 %s\n","000".matches(regex));//00.1
    System.out.printf("0. %s\n","000".matches(regex));//0.
    System.out.printf(".0 %s\n","000".matches(regex));//.0
    System.out.printf("11. %s\n","000".matches(regex));//11.
    System.out.printf("-0 %s\n","-0".matches(regex));//-0
    System.out.printf("+0 %s\n","+0".matches(regex));//+0
    //想要限制小数精度，直接把小数部分的\d+改为\d{精度}即可，例如限制两位小数精度则为"[+-]?(^0|[1-9]\\d*)(\\.\\d{2})?"
    regex = "[+-]?(^0|[1-9]\\d*)(\\.\\d{2})?";
    System.out.println("想要限制小数精度=============================================");
    System.out.printf("精度不够 10.2 %s\n","10.2".matches(regex));
    System.out.printf("精度超出 10.2345 %s\n","10.2345".matches(regex));
    System.out.printf("多个0也不行 00.23 %s\n","00.23".matches(regex));
    System.out.printf("精度正好 10.23 %s\n","10.23".matches(regex));
    System.out.printf("精度正好 0.23 %s\n","0.23".matches(regex));
}

0 true
10 true
+10 true
-10 true
10.23 true
0.23 true
+10.23 true
-10.23 true
异常数字验证=============================================
000 false
00.1 false
0. false
.0 false
11. false
-0 false
+0 false
想要限制小数精度=============================================
精度不够 10.2 false
精度超出 10.2345 false
多个0也不行 00.23 false
精度正好 10.23 true
精度正好 0.23