add convertor for cache

+package cache
+
+import (
+	"fmt"
+	"strconv"
+)
+
+func GetString(v interface{}) string {
+	switch result := v.(type) {
+	case string:
+		return result
+	case []byte:
+		return string(result)
+	default:
+		if v == nil {
+			return ""
+		} else {
+			return fmt.Sprintf("%v", result)
+		}
+	}
+}
+
+func GetInt(v interface{}) int {
+	switch result := v.(type) {
+	case int:
+		return result
+	case int32:
+		return int(result)
+	case int64:
+		return int(result)
+	default:
+		d := GetString(v)
+		if d != "" {
+			value, err := strconv.Atoi(d)
+			if err == nil {
+				return value
+			}
+		}
+	}
+	return 0
+}
+
+func GetInt64(v interface{}) int64 {
+	switch result := v.(type) {
+	case int:
+		return int64(result)
+	case int32:
+		return int64(result)
+	case int64:
+		return result
+	default:
+		d := GetString(v)
+		if d != "" {
+			result, err := strconv.ParseInt(d, 10, 64)
+			if err == nil {
+				return result
+			}
+		}
+	}
+	return 0
+}
+
+func GetFloat64(v interface{}) float64 {
+	switch result := v.(type) {
+	case float64:
+		return result
+	default:
+		d := GetString(v)
+		if d != "" {
+			value, err := strconv.ParseFloat(d, 64)
+			if err == nil {
+				return value
+			}
+		}
+	}
+	return 0
+}
+
+func GetBool(v interface{}) bool {
+	switch result := v.(type) {
+	case bool:
+		return result
+	default:
+		d := GetString(v)
+		if d != "" {
+			result, err := strconv.ParseBool(d)
+			if err == nil {
+				return result
+			}
+		}
+	}
+	return false
+}
+
+func getByteArray(v interface{}) []byte {
+	switch result := v.(type) {
+	case []byte:
+		return result
+	case string:
+		return []byte(result)
+	default:
+		return nil
+	}
+}

+package cache
+
+import (
+	"testing"
+)
+
+func TestGetString(t *testing.T) {
+	var t1 = "test1"
+	if "test1" != GetString(t1) {
+		t.Error("get string from string error")
+	}
+	var t2 = []byte("test2")
+	if "test2" != GetString(t2) {
+		t.Error("get string from byte array error")
+	}
+	var t3 int = 1
+	if "1" != GetString(t3) {
+		t.Error("get string from int error")
+	}
+	var t4 int64 = 1
+	if "1" != GetString(t4) {
+		t.Error("get string from int64 error")
+	}
+	var t5 float64 = 1.1
+	if "1.1" != GetString(t5) {
+		t.Error("get string from float64 error")
+	}
+
+	if "" != GetString(nil) {
+		t.Error("get string from nil error")
+	}
+}
+
+func TestGetInt(t *testing.T) {
+	var t1 int = 1
+	if 1 != GetInt(t1) {
+		t.Error("get int from int error")
+	}
+	var t2 int32 = 32
+	if 32 != GetInt(t2) {
+		t.Error("get int from int32 error")
+	}
+	var t3 int64 = 64
+	if 64 != GetInt(t3) {
+		t.Error("get int from int64 error")
+	}
+	var t4 = "128"
+	if 128 != GetInt(t4) {
+		t.Error("get int from num string error")
+	}
+	if 0 != GetInt(nil) {
+		t.Error("get int from nil error")
+	}
+}
+
+func TestGetInt64(t *testing.T) {
+	var i int64 = 1
+	var t1 int = 1
+	if i != GetInt64(t1) {
+		t.Error("get int64 from int error")
+	}
+	var t2 int32 = 1
+	if i != GetInt64(t2) {
+		t.Error("get int64 from int32 error")
+	}
+	var t3 int64 = 1
+	if i != GetInt64(t3) {
+		t.Error("get int64 from int64 error")
+	}
+	var t4 = "1"
+	if i != GetInt64(t4) {
+		t.Error("get int64 from num string error")
+	}
+	if 0 != GetInt64(nil) {
+		t.Error("get int64 from nil")
+	}
+}
+
+func TestGetFloat64(t *testing.T) {
+	var f float64 = 1.11
+	var t1 float32 = 1.11
+	if f != GetFloat64(t1) {
+		t.Error("get float64 from float32 error")
+	}
+	var t2 float64 = 1.11
+	if f != GetFloat64(t2) {
+		t.Error("get float64 from float64 error")
+	}
+	var t3 = "1.11"
+	if f != GetFloat64(t3) {
+		t.Error("get float64 from string error")
+	}
+
+	var f2 float64 = 1
+	var t4 int = 1
+	if f2 != GetFloat64(t4) {
+		t.Error("get float64 from int error")
+	}
+
+	if 0 != GetFloat64(nil) {
+		t.Error("get float64 from nil error")
+	}
+}
+
+func TestGetBool(t *testing.T) {
+	var t1 = true
+	if true != GetBool(t1) {
+		t.Error("get bool from bool error")
+	}
+	var t2 = "true"
+	if true != GetBool(t2) {
+		t.Error("get bool from string error")
+	}
+	if false != GetBool(nil) {
+		t.Error("get bool from nil error")
+	}
+}
+
+func TestGetByteArray(t *testing.T) {
+	var b = []byte("test")
+	var t1 = []byte("test")
+	if !byteArrayEquals(b, getByteArray(t1)) {
+		t.Error("get byte array from byte array error")
+	}
+	var t2 = "test"
+	if !byteArrayEquals(b, getByteArray(t2)) {
+		t.Error("get byte array from string error")
+	}
+	if nil != getByteArray(nil) {
+		t.Error("get byte array from nil error")
+	}
+}
+
+func byteArrayEquals(a []byte, b []byte) bool {
+	if len(a) != len(b) {
+		return false
+	}
+	for i, v := range a {
+		if v != b[i] {
+			return false
+		}
+	}
+	return true
+}