Add StructUtil for provide more rich functions (#79)

* add support json tag attribute for StructToMap function

* add the structutil to provide more rich functions and fixed #77

structutil/struct_test.go

@@ -0,0 +1,57 @@
+package structutil
+
+import (
+	"github.com/duke-git/lancet/v2/internal"
+	"testing"
+)
+
+func TestToMap(t *testing.T) {
+	assert := internal.NewAssert(t, "TestStructToMap")
+
+	t.Run("StructToMap", func(_ *testing.T) {
+		type People struct {
+			Name string `json:"name"`
+			age  int
+		}
+		p := People{
+			"test",
+			100,
+		}
+		pm, _ := ToMap(p)
+		var expected = map[string]any{"name": "test"}
+		assert.Equal(expected, pm)
+	})
+
+	t.Run("StructToMapWithJsonAttr", func(_ *testing.T) {
+		type People struct {
+			Name      string `json:"name,omitempty"` // json tag with attribute
+			Phone     string `json:"phone"`          // json tag without attribute
+			Sex       string `json:"-"`              // ignore by "-"
+			Age       int    // ignore by no tag
+			email     string // ignore by unexported
+			IsWorking bool   `json:"is_working"`
+		}
+		p1 := People{
+			Name:  "AAA", // exist
+			Phone: "1111",
+			Sex:   "male",
+			Age:   100,
+			email: "11@gmail.com",
+		}
+		p1m, _ := ToMap(p1)
+		var expect1 = map[string]any{"name": "AAA", "phone": "1111", "is_working": false}
+		assert.Equal(expect1, p1m)
+
+		p2 := People{
+			Name:      "",
+			Phone:     "2222",
+			Sex:       "male",
+			Age:       0,
+			email:     "22@gmail.com",
+			IsWorking: true,
+		}
+		p2m, _ := ToMap(p2)
+		var expect2 = map[string]any{"phone": "2222", "is_working": true}
+		assert.Equal(expect2, p2m)
+	})
+}