利用反射将bean转化为JsonString输出 （改进版）
利用反射将bean转化为JsonString输出 这个例子中，有好几种类型没有考虑到，特别是StringBuilder 、泛型等。泛型我还没想好如何处理，先添加StringBuilder及其他的类型，并调整一下代码方式。泛型想好如何处理了再更新此篇。
package
hlm.com.json;
import
java.io.Serializable;
import
java.util.Date;
public
class
User<
T
>
implements
Serializable {
private
static
final
long
serialVersionUID
= -6562205181367715396L;
private
String
name
;
private
String
sex
;
private
Integer
age
;
private
Date
birth
;
private
Dept
dept
;
private
boolean
isManager
;
private
T
type
;
private
StringBuilder
stringBuilder
;
public
String getName() {
return
name
;
}
public
void
setName(String
name
) {
this
.
name
=
name
;
}
public
String getSex() {
return
sex
;
}
public
void
setSex(String
sex
) {
this
.
sex
=
sex
;
}
public
Integer getAge() {
return
age
;
}
public
void
setAge(Integer
age
) {
this
.
age
=
age
;
}
public
Date getBirth() {
return
birth
;
}
public
void
setBirth(Date
birth
) {
this
.
birth
=
birth
;
}
public
Dept getDept() {
return
dept
;
}
public
void
setDept(Dept
dept
) {
this
.
dept
=
dept
;
}
public
boolean
getIsManager() {
return
isManager
;
}
public
void
setIsManager(
boolean
isManager
) {
this
.
isManager
=
isManager
;
}
public
T
getType() {
return
type
;
}
public
void
setType(
T
type
) {
this
.
type
=
type
;
}
public
StringBuilder getStringBuilder() {
return
stringBuilder
;
}
public
void
setStringBuilder(StringBuilder
stringBuilder
) {
this
.
stringBuilder
=
stringBuilder
;
}
}
package
hlm.com.json;
import
java.math.BigDecimal;
public
class
Dept {
private
String
deptName
;
private
Integer
deptNo
;
private
Object
deptManager
;
private
byte
num
;
private
BigDecimal
bigDecimal
;
public
String
getDeptName() {
return
deptName
;
}
public
void
setDeptName(String
deptName
) {
this
.
deptName
=
deptName
;
}
public
Integer getDeptNo() {
return
deptNo
;
}
public
void
setDeptNo(Integer
deptNo
) {
this
.
deptNo
=
deptNo
;
}
public
Object getDeptManager() {
return
deptManager
;
}
public
void
setDeptManager(Object
deptManager
) {
this
.
deptManager
=
deptManager
;
}
public
byte
getNum() {
return
num
;
}
public
void
setNum(
byte
num
) {
this
.
num
=
num
;
}
public
BigDecimal getBigDecimal() {
return
bigDecimal
;
}
public
void
setBigDecimal(BigDecimal
bigDecimal
) {
this
.
bigDecimal
=
bigDecimal
;
}
}
package
hlm.com.json;
import
java.lang.reflect.Field;
import
java.lang.reflect.InvocationTargetException;
import
java.lang.reflect.Method;
import
java.lang.reflect.ParameterizedType
;
import
java.lang.reflect.Type;
import
java.util.ArrayList;
import
org.apache.commons.logging.Log;
import
org.apache.commons.logging.LogFactory;
import
org.springframework.util.StringUtils;
public
class
JSONUtils {
private
static
final
Log
logger
= LogFactory.
getLog
(JSONUtils.
class
);
private
static
ArrayList();
static
{
baseType
.add(
"java.lang.String"
);
baseType
.add(
"java.util.Date"
);
baseType
.add(
"java.sql.Date"
);
baseType
.add(
"java.lang.Integer"
);
baseType
.add(
"java.lang.Long"
);
baseType
.add(
"java.lang.Byte"
);
baseType
.add(
"java.lang.Double"
);
baseType
.add(
"java.lang.Foalt"
);
baseType
.add(
"java.lang.Boolean"
);
baseType
.add(
"java.math.BigDecimal"
);
baseType
.add(
"boolean"
);
baseType
.add(
"byte"
);
baseType
.add(
"int"
);
baseType
.add(
"long"
);
baseType
.add(
"float"
);
baseType
.add(
"double"
);
baseType
.add(
"java.lang.Object"
);
baseType
.add(
"java.lang.String"
);
baseType
.add(
"java.lang.StringBuilder"
);
}
/**
* 返回 {"deptName":"研发部","deptNo":1001,"deptManager":"小刚"} 样子的字符串
*
@param
obj
*
@return
*/
public
static
String transferBean2JsonString(Object
obj
){
//获取Class 对象
Class
extends
Object>
clzz
=
obj
.getClass();
//获取属性数组
Field[]
fieldArray
=
clzz
.getDeclaredFields();
//容器
StringBuffer
sb
=
new
StringBuffer();
//循环
for
(Field
field
:
fieldArray
){
String
name
=
field
.getName();
//System.out.println(name);
logger
.info(
"name :"
+
name
);
Type
type
=
field
.getGenericType();
//System.out.println(type);
logger
.info(
"type :"
+
type
);
try
{
Method
method
=
clzz
.getMethod(
"get"
+
name
.substring(0, 1).toUpperCase()+
name
.substring(1),
null
)
;
Object
returnValue
=
method
.invoke(
obj
,
null
)
;
if
(
returnValue
!=
null
){
if
(
isBaseType
(
type
)){
sb
.append(
buildString
(
addStringMark
(
name
,String.
class
) ,
addStringMark
(
returnValue
,
type
)));
logger
.info(
"returnValue :"
+
returnValue
);
}
else
{
String
returnStr
=
transferBean2JsonString
(
returnValue
);
sb
.append(
buildString
(
addStringMark
(
name
,String.
class
) ,
addStringMark
(
returnStr
,
type
)));
logger
.info(
"returnValue :"
+
returnStr
);
}
}
}
catch
(NoSuchMethodException
e
) {
continue
;
}
catch
(SecurityException
e
) {
e
.printStackTrace();
}
catch
(IllegalAccessException
e
) {
e
.printStackTrace();
}
catch
(IllegalArgumentException
e
) {
e
.printStackTrace();
}
catch
(InvocationTargetException
e
) {
e
.printStackTrace();
}
}
//for end
return
buildObjectString
(
sb
);
}
/**
* 判断基础类型
*
@param
type
*
@return
*/
public
static
boolean
isBaseType(Type
type
){
if
(
type
==
null
)
return
false
;
if
(
baseType
.contains(
type
.getTypeName())){
return
true
;
}
return
false
;
}
public
static
String buildString(Object
name
,Object
returnValue
){
if
(
returnValue
==
null
|| StringUtils.
isEmpty
(
name
)){
return
null
;
}
return
name
+
":"
+
returnValue
.toString()+
","
;
}
/**
* 为某个对象加上大括号
*
@param
sb
*
@return
*/
public
static
String buildObjectString(StringBuffer
sb
){
if
(
sb
==
null
|| StringUtils.
isEmpty
(
sb
.toString()))
return
""
;
String
returnStr
=
sb
.toString();
returnStr
=
returnStr
.substring(0,
returnStr
.length()-1);
return
"{"
+
returnStr
+
"}"
;
}
/**
* 为String 类型的值为双引号
*
@return
*/
public
static
Object addStringMark(Object
value
,Type
type
){
if
(
value
!=
null
&&
type
.getTypeName().indexOf(
"StringBuilder"
)>=0){
return
"\""
+
value
.toString() +
"\""
;
}
else
if
(
value
!=
null
&&
type
.getTypeName().indexOf(
"String"
)>=0){
return
"\""
+
value
+
"\""
;
}
return
value
;
}
}
package
hlm.com.json;
import
java.math.BigDecimal;
import
java.text.DateFormat;
import
java.text.ParseException;
import
java.text.SimpleDateFormat;
import
java.util.Date;
import
com.alibaba.fastjson.JSONObject;
public
class
Test {
public
static
void
main(String[]
args
) {
Dept
dept
=
new
Dept() ;
dept
.setDeptNo(1001);
dept
.setDeptName(
"研发部"
);
dept
.setDeptManager(
"刘德华"
);
dept
.setNum((
byte
) 0);
dept
.setBigDecimal(
new
BigDecimal(1000000));
User
user
=
new
User
();
user
.setAge(22);
DateFormat
dateFormat
=
new
SimpleDateFormat(
"yyyy-MM-dd"
);
Date
birth
=
null
;
try
{
birth
=
dateFormat
.parse(
"2010-10-01"
);
}
catch
(ParseException
e
) {
e
.printStackTrace();
}
user
.setBirth(
birth
);
user
.setSex(
"男"
);
user
.setDept(
dept
);
user
.setName(
"小明"
);
user
.setAge(20);
user
.setIsManager(
false
);
user
.setType(
"type"
)
;
user
.setStringBuilder(
new
StringBuilder(
"stringBuilder"
));
String
userJSONString
= JSONUtils.
transferBean2JsonString
(
user
);
//找了一个别人写的方法来对比
String
Str
= JSONObject.
toJSONString
(
user
);
System.
out
.println(
userJSONString
);
System.
out
.println(
Str
);
}
}
结果：
22:57:13.858 [main] INFO hlm.com.json.JSONUtils - name :serialVersionUID
22:57:13.862 [main] INFO hlm.com.json.JSONUtils - type :long
22:57:13.862 [main] INFO hlm.com.json.JSONUtils - name :name
22:57:13.862 [main] INFO hlm.com.json.JSONUtils - type :class java.lang.String
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - returnValue :小明
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - name :sex
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - type :class java.lang.String
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - returnValue :男
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - name :age
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - type :class java.lang.Integer
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - returnValue :20
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - name :birth
22:57:13.864 [main] INFO hlm.com.json.JSONUtils - type :class java.util.Date
22:57:13.866 [main] INFO hlm.com.json.JSONUtils - returnValue :Fri Oct 01 00:00:00 CST 2010
22:57:13.866 [main] INFO hlm.com.json.JSONUtils - name :dept
22:57:13.866 [main] INFO hlm.com.json.JSONUtils - type :class hlm.com.json.Dept
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - name :deptName
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - type :class java.lang.String
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - returnValue :研发部
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - name :deptNo
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - type :class java.lang.Integer
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - returnValue :1001
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - name :deptManager
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - type :class java.lang.Object
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - returnValue :刘德华
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - name :num
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - type :byte
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - returnValue :0
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - name :bigDecimal
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - type :class java.math.BigDecimal
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - returnValue :1000000
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - returnValue :{"deptName":"研发部","deptNo":1001,"deptManager":刘德华,"num":0,"bigDecimal":1000000}
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - name :isManager
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - type :boolean
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - returnValue :false
22:57:13.867 [main] INFO hlm.com.json.JSONUtils - name :type
22:57:13.871 [main] INFO hlm.com.json.JSONUtils - type :T
22:57:13.872 [main] INFO hlm.com.json.JSONUtils - name :value
22:57:13.872 [main] INFO hlm.com.json.JSONUtils - type :class [C
22:57:13.872 [main] INFO hlm.com.json.JSONUtils - name :hash
22:57:13.872 [main] INFO hlm.com.json.JSONUtils - type :int
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - name :serialVersionUID
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - type :long
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - name :serialPersistentFields
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - type :class [Ljava.io.ObjectStreamField;
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - name :CASE_INSENSITIVE_ORDER
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - type :java.util.Comparator
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - returnValue :
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - name :stringBuilder
22:57:13.873 [main] INFO hlm.com.json.JSONUtils - type :class java.lang.StringBuilder
22:57:13.874 [main] INFO hlm.com.json.JSONUtils - returnValue :stringBuilder
{"name":"小明","sex":"男","age":20,"birth":Fri Oct 01 00:00:00 CST 2010,"dept":{"deptName":"研发部","deptNo":1001,"deptManager":刘德华,"num":0,"bigDecimal":1000000},"isManager":false,"type":,"stringBuilder":"stringBuilder"}
{"age":20,"birth":1285862400000,"dept":{"bigDecimal":1000000,"deptManager":"刘德华","deptName":"研发部","deptNo":1001,"num":0},"isManager":false,"name":"小明","sex":"男","stringBuilder":"stringBuilder","type":"type"}
1.泛型未处理，所以空掉了；
2.当一个属性没有set 方法时表示默认该字段是不能取到值的，所以在异常处直接进入下一轮了。