diff --git a/infra/string.go b/infra/string.go
new file mode 100644
index 0000000..569ce26
--- /dev/null
+++ b/infra/string.go
@@ -0,0 +1,189 @@
+package infra
+
+import (
+	"strings"
+	"unicode"
+)
+
+// SplitCase 转换驼峰字符串为用delimiter分隔的字符串
+// example: delimiter = '_'
+// 空字符 -> 空字符
+// HelloWorld -> hello_world
+// Hello_World -> hello_world
+// HiHello_World -> hi_hello_world
+// IdCom -> id_com
+// Idcom -> idcom
+// nameIdCom -> name_id_com
+// nameIdcom -> name_idcom
+func SplitCase(str string, delimiter byte) string {
+	str = strings.TrimSpace(str)
+	if str == "" {
+		return ""
+	}
+	var isPrevSpecial bool
+
+	t := make([]byte, 0, len(str)+8)
+	// Invariant: if the next letter is lower case, it must be converted
+	// to upper case.
+	// That is, we process a word at a time, where words are marked by _ or
+	// upper case letter. Digits are treated as words.
+	for i := 0; i < len(str); i++ {
+		c := str[i]
+		isCureNumber := isASCIIDigit(c)
+		if isCureNumber {
+			if i == 0 {
+				t = append(t, 'x', delimiter)
+			}
+		} else {
+			if isASCIIUpper(c) {
+				c += 'a' - 'A'
+				if i > 0 && !isPrevSpecial {
+					t = append(t, delimiter)
+				}
+			}
+		}
+		isPrevSpecial = isCureNumber || c == delimiter
+		t = append(t, c) // Guaranteed not lower case.
+	}
+	return string(t)
+}
+
+func JoinCase(s string, delimiter byte) string {
+	s = strings.TrimSpace(s)
+	if s == "" {
+		return ""
+	}
+	t := make([]byte, 0, 32)
+	i := 0
+	if s[0] == delimiter {
+		// Need a capital letter; drop the delimiter.
+		t = append(t, 'X')
+		i++
+	}
+	// Invariant: if the next letter is lower case, it must be converted
+	// to upper case.
+	// That is, we process a word at a time, where words are marked by _ or
+	// upper case letter. Digits are treated as words.
+	for ; i < len(s); i++ {
+		c := s[i]
+		if c == delimiter && i+1 < len(s) && isASCIILower(s[i+1]) {
+			continue // Skip the underscore in s.
+		}
+		if isASCIIDigit(c) {
+			t = append(t, c)
+			continue
+		}
+		// Assume we have a letter now - if not, it's a bogus identifier.
+		// The next word is a sequence of characters that must start upper case.
+		if isASCIILower(c) {
+			c ^= ' ' // Make it a capital letter.
+		}
+		t = append(t, c) // Guaranteed not lower case.
+		// Accept lower case sequence that follows.
+		for i+1 < len(s) && isASCIILower(s[i+1]) {
+			i++
+			t = append(t, s[i])
+		}
+	}
+	return string(t)
+}
+
+// SnakeCase 转换驼峰字符串为用'_'分隔的字符串
+// example2: delimiter = '_' initialisms = DefaultInitialisms
+// IdCom -> id_com
+// Idcom -> idcom
+// nameIdCom -> name_id_com
+// nameIdcom -> name_idcom
+func SnakeCase(str string) string {
+	return SplitCase(str, '_')
+}
+
+// Kebab 转换驼峰字符串为用'-'分隔的字符串
+// example2: delimiter = '-' initialisms = DefaultInitialisms
+// IdCom -> id-com
+// Idcom -> idcom
+// nameIdCom -> name-id-com
+// nameIdcom -> name-idcom
+func Kebab(str string) string {
+	return SplitCase(str, '-')
+}
+
+// SmallCamelCase to small camel case string
+// id_com -> idCom
+// idcom -> idcom
+// name_id_com -> nameIdCom
+// name_idcom -> nameIdcom
+func SmallCamelCase(fieldName string) string {
+	return LowTitle(CamelCase(fieldName))
+}
+
+// CamelCase returns the CamelCased name.
+// If there is an interior underscore followed by a lower case letter,
+// drop the underscore and convert the letter to upper case.
+// There is a remote possibility of this rewrite causing a name collision,
+// but it's so remote we're prepared to pretend it's nonexistent - since the
+// C++ generator lowercases names, it's extremely unlikely to have two fields
+// with different capitalizations.
+// In short, _my_field_name_2 becomes XMyFieldName_2.
+func CamelCase(s string) string {
+	return JoinCase(s, '_')
+}
+
+// LowTitle 首字母小写
+// see strings.Title
+func LowTitle(s string) string {
+	// Use a closure here to remember state.
+	// Hackish but effective. Depends on Map scanning in order and calling
+	// the closure once per rune.
+	prev := ' '
+	return strings.Map(func(r rune) rune {
+		if isSeparator(prev) {
+			prev = r
+			return unicode.ToLower(r)
+		}
+		prev = r
+		return r
+	}, s)
+}
+
+// Is c an ASCII upper-case letter?
+func isASCIIUpper(c byte) bool {
+	return 'A' <= c && c <= 'Z'
+}
+
+// Is c an ASCII lower-case letter?
+func isASCIILower(c byte) bool {
+	return 'a' <= c && c <= 'z'
+}
+
+// Is c an ASCII digit?
+func isASCIIDigit(c byte) bool {
+	return '0' <= c && c <= '9'
+}
+
+// isSeparator reports whether the rune could mark a word boundary.
+// TODO: update when package unicode captures more of the properties.
+// see strings isSeparator
+func isSeparator(r rune) bool {
+	// ASCII alphanumerics and underscore are not separators
+	if r <= 0x7F {
+		switch {
+		case r >= '0' && r <= '9':
+			return false
+		case r >= 'a' && r <= 'z':
+			return false
+		case r >= 'A' && r <= 'Z':
+			return false
+		case r == '_':
+			return false
+		}
+		return true
+	}
+
+	// Letters and digits are not separators
+	if unicode.IsLetter(r) || unicode.IsDigit(r) {
+		return false
+	}
+	// Otherwise, all we can do for now is treat spaces as separators.
+	return unicode.IsSpace(r)
+}
diff --git a/infra/string_test.go b/infra/string_test.go
new file mode 100644
index 0000000..426bf0b
--- /dev/null
+++ b/infra/string_test.go
@@ -0,0 +1,17 @@
+package infra
+
+import (
+	"testing"
+)
+
+func Test_SnakeCase(t *testing.T) {
+	if got, want := SnakeCase("PabB2BicNotify"), "pab_b2bic_notify"; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}
+
+func Test_CamelCase(t *testing.T) {
+	if got, want := CamelCase("pab_b2bic_notify"), "PabB2BicNotify"; got != want {
+		t.Errorf("got %v, want %v", got, want)
+	}
+}