diff --git a/.travis.yml b/.travis.yml
index 5c05fa0a4..d277b54d3 100644
--- a/.travis.yml
+++ b/.travis.yml
@@ -21,7 +21,7 @@ addons:
   - local
 
 before_install:
-- pwd
+  - mysql -e 'CREATE DATABASE IF NOT EXISTS test;'
 
 install:
 - cat /etc/hosts
diff --git a/g/encoding/gjson/gjson_api.go b/g/encoding/gjson/gjson_api.go
index 29fb1c371..04854860a 100644
--- a/g/encoding/gjson/gjson_api.go
+++ b/g/encoding/gjson/gjson_api.go
@@ -10,6 +10,8 @@ import (
 	"fmt"
 	"time"
 
+	"github.com/gogf/gf/g/util/gutil"
+
 	"github.com/gogf/gf/g/container/gvar"
 	"github.com/gogf/gf/g/os/gtime"
 	"github.com/gogf/gf/g/util/gconv"
@@ -22,6 +24,13 @@ func (j *Json) Value() interface{} {
 	return *(j.p)
 }
 
+// IsNil checks whether the value pointed by <j> is nil.
+func (j *Json) IsNil() bool {
+	j.mu.RLock()
+	defer j.mu.RUnlock()
+	return j.p == nil || *(j.p) == nil
+}
+
 // Get returns value by specified <pattern>.
 // It returns all values of current Json object, if <pattern> is empty or not specified.
 // It returns nil if no value found by <pattern>.
@@ -67,11 +76,7 @@ func (j *Json) GetMap(pattern string, def ...interface{}) map[string]interface{}
 // GetJson gets the value by specified <pattern>,
 // and converts it to a un-concurrent-safe Json object.
 func (j *Json) GetJson(pattern string, def ...interface{}) *Json {
-	result := j.Get(pattern, def...)
-	if result != nil {
-		return New(result, true)
-	}
-	return nil
+	return New(j.Get(pattern, def...), true)
 }
 
 // GetJsons gets the value by specified <pattern>,
@@ -257,6 +262,7 @@ func (j *Json) Append(pattern string, value interface{}) error {
 // GetToVar gets the value by specified <pattern>,
 // and converts it to specified golang variable <v>.
 // The <pointer> should be a pointer type.
+// Deprecated.
 func (j *Json) GetToVar(pattern string, pointer interface{}) error {
 	r := j.Get(pattern)
 	if r != nil {
@@ -342,13 +348,15 @@ func (j *Json) ToStructsDeep(pointer interface{}) error {
 }
 
 // Dump prints current Json object with more manually readable.
-func (j *Json) Dump() error {
+func (j *Json) Dump() {
 	j.mu.RLock()
 	defer j.mu.RUnlock()
-	if b, err := j.ToJsonIndent(); err != nil {
-		return err
-	} else {
-		fmt.Println(string(b))
-	}
-	return nil
+	gutil.Dump(*j.p)
+}
+
+// Export returns <j> as a string with more manually readable.
+func (j *Json) Export() string {
+	j.mu.RLock()
+	defer j.mu.RUnlock()
+	return gutil.Export(*j.p)
 }
diff --git a/g/encoding/gjson/gjson_z_unit_basic_test.go b/g/encoding/gjson/gjson_z_unit_basic_test.go
index b65cdba36..8d13d1240 100644
--- a/g/encoding/gjson/gjson_z_unit_basic_test.go
+++ b/g/encoding/gjson/gjson_z_unit_basic_test.go
@@ -7,10 +7,11 @@
 package gjson_test
 
 import (
+	"testing"
+
 	"github.com/gogf/gf/g"
 	"github.com/gogf/gf/g/encoding/gjson"
 	"github.com/gogf/gf/g/test/gtest"
-	"testing"
 )
 
 func Test_New(t *testing.T) {
@@ -361,7 +362,7 @@ func Test_Convert2(t *testing.T) {
 		err := j.ToStruct(&name)
 		gtest.Assert(err, nil)
 		gtest.Assert(name.Name, "gf")
-		err = j.Dump()
+		j.Dump()
 		gtest.Assert(err, nil)
 
 		j = gjson.New(`{"person":{"name":"gf"}}`)
@@ -370,7 +371,7 @@ func Test_Convert2(t *testing.T) {
 		gtest.Assert(name.Name, "gf")
 
 		j = gjson.New(`{"name":"gf""}`)
-		err = j.Dump()
+		j.Dump()
 		gtest.Assert(err, nil)
 
 		j = gjson.New(`[1,2,3]`)
@@ -459,3 +460,10 @@ func Test_Basic(t *testing.T) {
 
 	})
 }
+
+func Test_IsNil(t *testing.T) {
+	gtest.Case(t, func() {
+		j := gjson.New(nil)
+		gtest.Assert(j.IsNil(), true)
+	})
+}
diff --git a/g/encoding/gparser/gparser_api.go b/g/encoding/gparser/gparser_api.go
index 2b5261a09..9be9f3c9b 100644
--- a/g/encoding/gparser/gparser_api.go
+++ b/g/encoding/gparser/gparser_api.go
@@ -7,9 +7,10 @@
 package gparser
 
 import (
+	"time"
+
 	"github.com/gogf/gf/g/container/gvar"
 	"github.com/gogf/gf/g/os/gtime"
-	"time"
 )
 
 // Val returns the value.
@@ -141,6 +142,7 @@ func (p *Parser) GetGTime(pattern string, format ...string) *gtime.Time {
 // GetToVar gets the value by specified <pattern>,
 // and converts it to specified golang variable <v>.
 // The <v> should be a pointer type.
+// Deprecated.
 func (p *Parser) GetToVar(pattern string, pointer interface{}) error {
 	return p.json.GetToVar(pattern, pointer)
 }
@@ -216,7 +218,23 @@ func (p *Parser) ToStruct(pointer interface{}) error {
 	return p.json.ToStruct(pointer)
 }
 
-// Dump prints current Json object with more manually readable.
-func (p *Parser) Dump() error {
-	return p.json.Dump()
+func (p *Parser) ToStructDeep(pointer interface{}) error {
+	return p.json.ToStructDeep(pointer)
+}
+
+func (p *Parser) ToStructs(pointer interface{}) error {
+	return p.json.ToStructs(pointer)
+}
+
+func (p *Parser) ToStructsDeep(pointer interface{}) error {
+	return p.json.ToStructsDeep(pointer)
+}
+
+// Dump prints current Json object with more manually readable.
+func (p *Parser) Dump() {
+	p.json.Dump()
+}
+
+func (p *Parser) Export() string {
+	return p.json.Export()
 }
diff --git a/g/frame/gins/gins_database_test.go b/g/frame/gins/gins_database_test.go
index 9f850cf39..32f2fd512 100644
--- a/g/frame/gins/gins_database_test.go
+++ b/g/frame/gins/gins_database_test.go
@@ -7,7 +7,6 @@
 package gins_test
 
 import (
-	"fmt"
 	"testing"
 	"time"
 
@@ -60,7 +59,7 @@ test = "v=2"
 	time.Sleep(500 * time.Millisecond)
 
 	gtest.Case(t, func() {
-		fmt.Println("gins Test_Database", gins.Config().Get("test"))
+		//fmt.Println("gins Test_Database", gins.Config().Get("test"))
 
 		dbDefault := gins.Database()
 		dbTest := gins.Database("test")
diff --git a/g/internal/strutils/strutils.go b/g/internal/strutils/strutils.go
new file mode 100644
index 000000000..9ac598f56
--- /dev/null
+++ b/g/internal/strutils/strutils.go
@@ -0,0 +1,60 @@
+// Copyright 2019 gf Author(https://github.com/gogf/gf). All Rights Reserved.
+//
+// This Source Code Form is subject to the terms of the MIT License.
+// If a copy of the MIT was not distributed with this file,
+// You can obtain one at https://github.com/gogf/gf.
+
+// Package strutils provides some string functions for internal usage.
+package strutils
+
+import "strings"
+
+// IsLetterUpper tests whether the given byte b is in upper case.
+func IsLetterUpper(b byte) bool {
+	if b >= byte('A') && b <= byte('Z') {
+		return true
+	}
+	return false
+}
+
+// IsLetterLower tests whether the given byte b is in lower case.
+func IsLetterLower(b byte) bool {
+	if b >= byte('a') && b <= byte('z') {
+		return true
+	}
+	return false
+}
+
+// IsNumeric tests whether the given string s is numeric.
+func IsNumeric(s string) bool {
+	length := len(s)
+	if length == 0 {
+		return false
+	}
+	for i := 0; i < len(s); i++ {
+		if s[i] < byte('0') || s[i] > byte('9') {
+			return false
+		}
+	}
+	return true
+}
+
+// UcFirst returns a copy of the string s with the first letter mapped to its upper case.
+func UcFirst(s string) string {
+	if len(s) == 0 {
+		return s
+	}
+	if IsLetterLower(s[0]) {
+		return string(s[0]-32) + s[1:]
+	}
+	return s
+}
+
+// ReplaceByMap returns a copy of <origin>,
+// which is replaced by a map in unordered way, case-sensitively.
+func ReplaceByMap(origin string, replaces map[string]string) string {
+	for k, v := range replaces {
+		origin = strings.Replace(origin, k, v, -1)
+	}
+	return origin
+}
diff --git a/g/os/gtime/gtime_format.go b/g/os/gtime/gtime_format.go
index 89915447d..d54edcfd4 100644
--- a/g/os/gtime/gtime_format.go
+++ b/g/os/gtime/gtime_format.go
@@ -8,10 +8,10 @@ package gtime
 
 import (
 	"bytes"
-	"github.com/gogf/gf/g/text/gregex"
-	"github.com/gogf/gf/g/text/gstr"
 	"strconv"
 	"strings"
+
+	"github.com/gogf/gf/g/text/gregex"
 )
 
 var (
@@ -110,9 +110,15 @@ func (t *Time) Format(format string) string {
 				// 有几个转换的符号需要特殊处理
 				switch runes[i] {
 				case 'j':
-					buffer.WriteString(gstr.ReplaceByArray(result, []string{"=j=0", "", "=j=", ""}))
+					for _, s := range []string{"=j=0", "=j="} {
+						result = strings.Replace(result, s, "", -1)
+					}
+					buffer.WriteString(result)
 				case 'G':
-					buffer.WriteString(gstr.ReplaceByArray(result, []string{"=G=0", "", "=G=", ""}))
+					for _, s := range []string{"=G=0", "=G="} {
+						result = strings.Replace(result, s, "", -1)
+					}
+					buffer.WriteString(result)
 				case 'u':
 					buffer.WriteString(strings.Replace(result, "=u=.", "", -1))
 				case 'w':
diff --git a/g/text/gstr/gstr.go b/g/text/gstr/gstr.go
index 0a0cdf9ca..7098bc2b8 100644
--- a/g/text/gstr/gstr.go
+++ b/g/text/gstr/gstr.go
@@ -10,12 +10,17 @@ package gstr
 import (
 	"bytes"
 	"fmt"
-	"github.com/gogf/gf/g/util/grand"
 	"math"
 	"strconv"
 	"strings"
 	"unicode"
 	"unicode/utf8"
+
+	"github.com/gogf/gf/g/internal/strutils"
+
+	"github.com/gogf/gf/g/util/gconv"
+
+	"github.com/gogf/gf/g/util/grand"
 )
 
 // Replace returns a copy of the string <origin>
@@ -93,10 +98,7 @@ func ReplaceIByArray(origin string, array []string) string {
 // ReplaceByMap returns a copy of <origin>,
 // which is replaced by a map in unordered way, case-sensitively.
 func ReplaceByMap(origin string, replaces map[string]string) string {
-	for k, v := range replaces {
-		origin = Replace(origin, k, v)
-	}
-	return origin
+	return strutils.ReplaceByMap(origin, replaces)
 }
 
 // ReplaceIByMap returns a copy of <origin>,
@@ -120,13 +122,7 @@ func ToUpper(s string) string {
 
 // UcFirst returns a copy of the string s with the first letter mapped to its upper case.
 func UcFirst(s string) string {
-	if len(s) == 0 {
-		return s
-	}
-	if IsLetterLower(s[0]) {
-		return string(s[0]-32) + s[1:]
-	}
-	return s
+	return strutils.UcFirst(s)
 }
 
 // LcFirst returns a copy of the string s with the first letter mapped to its lower case.
@@ -147,40 +143,25 @@ func UcWords(str string) string {
 
 // IsLetterLower tests whether the given byte b is in lower case.
 func IsLetterLower(b byte) bool {
-	if b >= byte('a') && b <= byte('z') {
-		return true
-	}
-	return false
+	return strutils.IsLetterLower(b)
 }
 
 // IsLetterUpper tests whether the given byte b is in upper case.
 func IsLetterUpper(b byte) bool {
-	if b >= byte('A') && b <= byte('Z') {
-		return true
-	}
-	return false
+	return strutils.IsLetterUpper(b)
 }
 
 // IsNumeric tests whether the given string s is numeric.
 func IsNumeric(s string) bool {
-	length := len(s)
-	if length == 0 {
-		return false
-	}
-	for i := 0; i < len(s); i++ {
-		if s[i] < byte('0') || s[i] > byte('9') {
-			return false
-		}
-	}
-	return true
+	return strutils.IsNumeric(s)
 }
 
 // SubStr returns a portion of string <str> specified by the <start> and <length> parameters.
 func SubStr(str string, start int, length ...int) (substr string) {
-	// 将字符串的转换成[]rune
+	// Converting to []rune to support unicode.
 	rs := []rune(str)
 	lth := len(rs)
-	// 简单的越界判断
+	// Simple border checks.
 	if start < 0 {
 		start = 0
 	}
@@ -197,7 +178,6 @@ func SubStr(str string, start int, length ...int) (substr string) {
 	if end > lth {
 		end = lth
 	}
-	// 返回子串
 	return string(rs[start:end])
 }
 
@@ -468,6 +448,14 @@ func Join(array []string, sep string) string {
 	return strings.Join(array, sep)
 }
 
+// JoinAny concatenates the elements of a to create a single string. The separator string
+// sep is placed between elements in the resulting string.
+//
+// The parameter <array> can be any type of slice.
+func JoinAny(array interface{}, sep string) string {
+	return strings.Join(gconv.Strings(array), sep)
+}
+
 // Explode splits string <str> by a string <delimiter>, to an array.
 // See http://php.net/manual/en/function.explode.php.
 func Explode(delimiter, str string) []string {
diff --git a/g/util/gconv/gconv_map.go b/g/util/gconv/gconv_map.go
index fcc3f691c..1d74da30a 100644
--- a/g/util/gconv/gconv_map.go
+++ b/g/util/gconv/gconv_map.go
@@ -11,7 +11,7 @@ import (
 	"strings"
 
 	"github.com/gogf/gf/g/internal/empty"
-	"github.com/gogf/gf/g/text/gstr"
+	"github.com/gogf/gf/g/internal/strutils"
 )
 
 // Map converts any variable <value> to map[string]interface{}.
@@ -116,7 +116,7 @@ func Map(value interface{}, tags ...string) map[string]interface{} {
 				for i := 0; i < rv.NumField(); i++ {
 					// Only convert the public attributes.
 					fieldName := rt.Field(i).Name
-					if !gstr.IsLetterUpper(fieldName[0]) {
+					if !strutils.IsLetterUpper(fieldName[0]) {
 						continue
 					}
 					name = ""
diff --git a/g/util/gconv/gconv_slice.go b/g/util/gconv/gconv_slice.go
index 2b7178bae..c76204889 100644
--- a/g/util/gconv/gconv_slice.go
+++ b/g/util/gconv/gconv_slice.go
@@ -11,7 +11,7 @@ import (
 	"fmt"
 	"reflect"
 
-	"github.com/gogf/gf/g/text/gstr"
+	"github.com/gogf/gf/g/internal/strutils"
 )
 
 // SliceInt is alias of Ints.
@@ -357,7 +357,7 @@ func Interfaces(i interface{}) []interface{} {
 				rt := rv.Type()
 				for i := 0; i < rv.NumField(); i++ {
 					// Only public attributes.
-					if !gstr.IsLetterUpper(rt.Field(i).Name[0]) {
+					if !strutils.IsLetterUpper(rt.Field(i).Name[0]) {
 						continue
 					}
 					array = append(array, rv.Field(i).Interface())
@@ -447,6 +447,10 @@ func doStructs(params interface{}, pointer interface{}, deep bool, mapping ...ma
 	}
 	switch kind {
 	case reflect.Slice, reflect.Array:
+		// If <params> is an empty slice, no conversion.
+		if rv.Len() == 0 {
+			return nil
+		}
 		array := reflect.MakeSlice(pointerRt.Elem(), rv.Len(), rv.Len())
 		itemType := array.Index(0).Type()
 		for i := 0; i < rv.Len(); i++ {
diff --git a/g/util/gconv/gconv_struct.go b/g/util/gconv/gconv_struct.go
index e3a0f5137..0bcff3644 100644
--- a/g/util/gconv/gconv_struct.go
+++ b/g/util/gconv/gconv_struct.go
@@ -13,7 +13,7 @@ import (
 	"strings"
 
 	"github.com/gogf/gf/g/internal/structs"
-	"github.com/gogf/gf/g/text/gstr"
+	"github.com/gogf/gf/g/internal/strutils"
 )
 
 // Struct maps the params key-value pairs to the corresponding struct object's properties.
@@ -92,7 +92,7 @@ func Struct(params interface{}, pointer interface{}, mapping ...map[string]strin
 	elemType := elem.Type()
 	for i := 0; i < elem.NumField(); i++ {
 		// Only do converting to public attributes.
-		if !gstr.IsLetterUpper(elemType.Field(i).Name[0]) {
+		if !strutils.IsLetterUpper(elemType.Field(i).Name[0]) {
 			continue
 		}
 		attrMap[elemType.Field(i).Name] = struct{}{}
@@ -100,8 +100,8 @@ func Struct(params interface{}, pointer interface{}, mapping ...map[string]strin
 	for mapK, mapV := range paramsMap {
 		name := ""
 		for _, checkName := range []string{
-			gstr.UcFirst(mapK),
-			gstr.ReplaceByMap(mapK, map[string]string{
+			strutils.UcFirst(mapK),
+			strutils.ReplaceByMap(mapK, map[string]string{
 				"_": "",
 				"-": "",
 				" ": "",
@@ -118,7 +118,7 @@ func Struct(params interface{}, pointer interface{}, mapping ...map[string]strin
 					name = value
 					break
 				}
-				if strings.EqualFold(checkName, gstr.Replace(value, "_", "")) {
+				if strings.EqualFold(checkName, strings.Replace(value, "_", "", -1)) {
 					name = value
 					break
 				}
@@ -159,7 +159,7 @@ func StructDeep(params interface{}, pointer interface{}, mapping ...map[string]s
 			rt := rv.Type()
 			for i := 0; i < rv.NumField(); i++ {
 				// Only do converting to public attributes.
-				if !gstr.IsLetterUpper(rt.Field(i).Name[0]) {
+				if !strutils.IsLetterUpper(rt.Field(i).Name[0]) {
 					continue
 				}
 				trv := rv.Field(i)
diff --git a/g/util/gconv/gconv_time.go b/g/util/gconv/gconv_time.go
index 90282e195..5d12ac48c 100644
--- a/g/util/gconv/gconv_time.go
+++ b/g/util/gconv/gconv_time.go
@@ -7,9 +7,10 @@
 package gconv
 
 import (
-	"github.com/gogf/gf/g/os/gtime"
-	"github.com/gogf/gf/g/text/gstr"
 	"time"
+
+	"github.com/gogf/gf/g/internal/strutils"
+	"github.com/gogf/gf/g/os/gtime"
 )
 
 // Time converts <i> to time.Time.
@@ -22,7 +23,7 @@ func Time(i interface{}, format ...string) time.Time {
 // If <i> is numeric, then it converts <i> as nanoseconds.
 func Duration(i interface{}) time.Duration {
 	s := String(i)
-	if !gstr.IsNumeric(s) {
+	if !strutils.IsNumeric(s) {
 		d, _ := time.ParseDuration(s)
 		return d
 	}
@@ -43,7 +44,7 @@ func GTime(i interface{}, format ...string) *gtime.Time {
 		t, _ := gtime.StrToTimeFormat(s, format[0])
 		return t
 	}
-	if gstr.IsNumeric(s) {
+	if strutils.IsNumeric(s) {
 		return gtime.NewFromTimeStamp(Int64(s))
 	} else {
 		t, _ := gtime.StrToTime(s)