matcher-java

示例1:正则表达式

// a(mn|xy)[0-9]+
Matcher m = ch('a').and(str("mn").or("xy")).and(range('0', '9').many1());
System.out.println(m.match("amn12345")); // true
System.out.println(m.match("axy123")); // true
System.out.println(m.match("ax12345")); // false
System.out.println(m.match("amnxy")); // false

示例2:括号匹配

/**
 * 括号匹配校验
 * expr = term+
 * term = "()"
 * | '(' expr ')'
 */
public class BracketMatcher {
 private static final Matcher term = oneOf(
 str("()"),
 ch('(').and(lazy(() -> BracketMatcher.expr)).and(')')
 );
 private static final Matcher expr = term.many1();
 public static boolean isBracketMatch(String s) {
 return expr.match(s);
 }
}
System.out.println(BracketMatcher.isBracketMatch("(())()")); // true 
System.out.println(BracketMatcher.isBracketMatch("(()()")); // false

示例3:算数表达式校验

/**
 * 算数表达式校验
 * expr = term ('+'|'-' term)+
 * term = fact ('*'|'/' fact)+
 * fact = [0-9]+
 * | '-' fact
 * | '(' expr ')'
 */
public class ArithmeticExprValidator {
 private static final Matcher fact = oneOf(
 range('0', '9').many1(),
 ch('-').and(lazy(() -> ArithmeticExprValidator.fact)),
 ch('(').and(lazy(() -> ArithmeticExprValidator.expr)).and(')')
 );
 private static final Matcher term = fact.and(chs('*', '/').and(fact).many());
 private static final Matcher expr = term.and(chs('+', '-').and(term).many());
 public static boolean isValidExpr(String s) {
 return expr.match(s);
 }
}
System.out.println(ArithmeticExprValidator.isValidExpr("(12+345)*(67-890)+10/6")); // true
System.out.println(ArithmeticExprValidator.isValidExpr("6+3-")); // false

示例4:JSON字符串校验

/**
 * json字符串校验
 * jsonObj = number | string | bool | arr | obj
 * number = integer | decimal
 * integer = [0-9]+
 * decimal = [0-9]+ '.' [0-9]+
 * string = '"' (.*) '"'
 * bool = "true" | "false"
 * arr = "[]"
 * | '[' jsonObj (',' jsonObj)* ']'
 * field = string ':' jsonObj
 * obj = "{}"
 * | '{' field (',' field)* '}'
 */
class JsonValidator {
 private static final Matcher blank = chs(' ', '\t', '\n', '\r').many();
 private static final Matcher objStart = withBlank(ch('{'));
 private static final Matcher objEnd = withBlank(ch('}'));
 private static final Matcher arrStart = withBlank(ch('['));
 private static final Matcher arrEnd = withBlank(ch(']'));
 private static final Matcher colon = withBlank(ch(':'));
 private static final Matcher comma = withBlank(ch(','));
 private static final Matcher jsonObj = oneOf(
 lazy(() -> JsonValidator.number),
 lazy(() -> JsonValidator.string),
 lazy(() -> JsonValidator.bool),
 lazy(() -> JsonValidator.arr),
 lazy(() -> JsonValidator.obj)
 );
 private static final Matcher digits = range('0', '9').many1();
 private static final Matcher integer = digits;
 private static final Matcher decimal = seq(digits, ch('.'), digits);
 private static final Matcher number = integer.or(decimal);
 private static final Matcher string = seq(ch('"'), not('"').many(), ch('"'));
 private static final Matcher bool = strs("true", "false");
 private static final Matcher arr = oneOf(
 arrStart.and(arrEnd),
 seq(arrStart, jsonObj.and(comma.and(jsonObj).many()), arrEnd)
 );
 private static final Matcher field = seq(string, colon, jsonObj);
 private static final Matcher obj = oneOf(
 objStart.and(objEnd),
 seq(objStart, field.and(comma.and(field).many()), objEnd)
 );
 
 private static Matcher withBlank(Matcher m) {
 return seq(blank, m, blank);
 }
 public static boolean isValidJson(String s) {
 return jsonObj.match(s);
 }
}
// true
System.out.println(JsonValidator.isValidJson("""
 {
 "a": 123,
 "b": 3.14,
 "c": "hello",
 "d": {
 "x": 100,
 "y": "world!"
 },
 "e": [
 12,
 34.56,
 {
 "name": "Xiao Ming",
 "age": 18,
 "score": [99.8, 87.5, 60.0]
 },
 "abc"
 ],
 "f": [],
 "g": {},
 "h": [true, {"m": false}]
 }"""));