Java正则表达式匹配字符串并提取中间的值
前言
有时候正则表达式不只是匹配一下什么数字/邮箱/身份证/日期等等,还需要匹配某一段文字,并按照既定格式提取其中的某些值.
场景一:提取SAML2报文
SAML2报文内容如下,从中提取对应的attribute name和value.
<saml:AttributeStatement>
<saml:Attribute Name="mail">
<saml:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">zhengkai.blog.csdn.netsaml:AttributeValue>
saml:Attribute>
<saml:Attribute Name="cn">
<saml:AttributeValue xmlns:xs="http://www.w3.org/2001/XMLSchema" xmlns:xsi="http://www.w3.org/2001/XMLSchema-instance" xsi:type="xs:string">amAdminsaml:AttributeValue>
saml:Attribute>
saml:AttributeStatement>
show time
public static void main(String[] args) {
String content = "";
content = "" ;
content += " " ;
content += " zhengkai.blog.csdn.net ";
content += " ";
content += " " ;
content += " amAdmin ";
content += " ";
content += "";
String pattern = "\\.*?)\\\"\\>[\\s\\S]*?\\(?.*?)\\<\\/saml\\:AttributeValue\\>[\\s\\S]*?\\<\\/saml\\:Attribute\\>" ;
Pattern r = Pattern.compile(pattern);
Matcher matcher = r.matcher(saml2attributeString);
while (matcher.find()){
String attributeName = matcher.group("scope");
String attributeValue = matcher.group("value");
System.out.println("attributeName->"+attributeName +",attributeValue->"+attributeValue );
}
}
控制台输出
$ attributeName->mail,attributeValue->zhengkai.blog.csdn.net
$ vattributeName->cn,attributeValue->amAdmin
解析
\\<saml\\:Attribute Name=\\\"(?<scope>.*?)\\\"\\>[\\s\\S]*?\\<saml\\:AttributeValue[\\s\\S]*?\\>(?<value>.*?)\\<\\/saml\\:AttributeValue\\>[\\s\\S]*?\\<\\/saml\\:Attribute\\>
(?是用于.*?) 标识scope的方式，表示夹在中间的字符串都叫scope，可以通过matcher.group("scope")提取。- 所有
非正则的符号都需要转义，所以你会看到很多\\<或者换\\"之类的\\ [\\s\\S]*?是用来匹配任意字符，表示在前后有界定的情况下（例如夹在忽略那些不规则字符串的匹配。
场景2:提取sql中的表名和字段
来自github网友@ydq 给SpringBootCodeGenerator贡献的正则表达式,非常不错,值得深刻学习.
//匹配整个ddl，将ddl分为表名，列sql部分，表注释
private static final Pattern DDL_PATTERN = Pattern.compile("\\s*create\\s+table\\s+(?\\S+)[^\\(]*\\((?[\\s\\S]+)\\)[^\\)]+?(comment\\s*(=|on\\s+table)\\s*'(?.*?)'\\s*;?)?$" , Pattern.CASE_INSENSITIVE);
//匹配列sql部分，分别解析每一列的列名 类型 和列注释
private static final Pattern COL_PATTERN = Pattern.compile("\\s*(?\\S+)\\s+(?\\w+)\\s*(?:\\([\\s\\d,]+\\))?((?!comment).)*(comment\\s*'(?.*?)')?\\s*(,|$)" , Pattern.CASE_INSENSITIVE);
public static void parse(String sql){
Matcher matcher = DDL_PATTERN.matcher(sql);
if (matcher.find()){
String tableName = matcher.group("tableName");
String tableComment = matcher.group("tableComment");
System.out.println(tableName + "\t\t" + tableComment);
System.out.println("==========");
String columnsSQL = matcher.group("columnsSQL");
if (columnsSQL != null && columnsSQL.length() > 0){
Matcher colMatcher = COL_PATTERN.matcher(columnsSQL);
while (colMatcher.find()){
String fieldName = colMatcher.group("fieldName");
String fieldType = colMatcher.group("fieldType");
String fieldComment = colMatcher.group("fieldComment");
if (!"key".equalsIgnoreCase(fieldType)){
System.out.println(fieldName + "\t\t" + fieldType + "\t\t" + fieldComment);
}
}
}
}
}
public static void main(String[] args){
System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
parse("CREATE TABLE `userinfo` (\n" +
" `user_id` int(11) NOT NULL AUTO_INCREMENT COMMENT '用户ID',\n" +
" `username` varchar(255) NOT NULL COMMENT '用户名',\n" +
" `addtime` datetime NOT NULL COMMENT '创建时间',\n" +
" PRIMARY KEY (`user_id`)\n" +
") ENGINE=InnoDB DEFAULT CHARSET=utf8 COMMENT='用户信息'");
System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
parse("CREATE TABLE `USER` (\n" +
"`ID` varchar(32) PRIMARY KEY COMMENT '主键',\n" +
"`password` varchar(32) NOT NULL COMMENT '密码',\n" +
"`username` varchar(32) NOT NULL COMMENT '用户'\n" +
") ENGINE=InnoDB DEFAULT CHARSET=utf8;");
System.out.println(">>>>>>>>>>>>>>>>>>>>>>>>>>>>>");
parse("CREATE TABLE `tb_amount` (\n" +
"`ID` int(10) NOT NULL AUTO_INCREMENT,\n" +
"`PRODUCT_CODE` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NOT NULL COMMENT '产品代码',\n" +
"`GENDER` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '性别(male,female)',\n" +
"`MIN_INSURED_AGE` int(3) NULL DEFAULT NULL COMMENT '最小投保年龄',\n" +
"`MAX_INSURED_AGE` int(3) NULL DEFAULT NULL COMMENT '最大投保年龄',\n" +
"`AMOUNT` double(10, 2) NULL DEFAULT NULL COMMENT '基本保额',\n" +
"`PREMIUM_RATE` double(10, 2) NULL DEFAULT NULL COMMENT '基本保费',\n" +
"`YEAR_NUM` int(3) NULL DEFAULT NULL COMMENT '缴费年限',\n" +
"`PREMIUM_TYPE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '费率类型',\n" +
"`INSURANCE_PERIOD` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '保险期间(30年，60年)',\n" +
"`INSURANCE_PERIOD_TYPE` varchar(50) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '保险期间类型(如定期年0,定期岁1,终身2,以后终身对应值：200)',\n" +
"`PAY_MODE` varchar(10) CHARACTER SET utf8mb4 COLLATE utf8mb4_0900_ai_ci NULL DEFAULT NULL COMMENT '交费方式',\n" +
"PRIMARY KEY (`ID`) USING BTREE\n" +
") ENGINE = InnoDB CHARACTER SET = utf8mb4 COLLATE = utf8mb4_0900_ai_ci ROW_FORMAT = Dynamic;");
}
控制台输出内容:
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
`userinfo` 用户信息
==========
`user_id` int 用户ID
`username` varchar 用户名
`addtime` datetime 创建时间
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
`USER` null
==========
`ID` varchar 主键
`password` varchar 密码
`username` varchar 用户
>>>>>>>>>>>>>>>>>>>>>>>>>>>>>
`tb_amount` null
==========
`ID` int null
`PRODUCT_CODE` varchar 产品代码
`GENDER` varchar 性别(male,female)
`MIN_INSURED_AGE` int 最小投保年龄
`MAX_INSURED_AGE` int 最大投保年龄
`AMOUNT` double 基本保额
`PREMIUM_RATE` double 基本保费
`YEAR_NUM` int 缴费年限
`PREMIUM_TYPE` varchar 费率类型
`INSURANCE_PERIOD` varchar 保险期间(30年，60年)
`INSURANCE_PERIOD_TYPE` varchar 保险期间类型(如定期年0,定期岁1,终身2,以后终身对应值：200)
`PAY_MODE` varchar 交费方式