JAVA枪手

JSON-lib框架，转换JSON、XML不再困难

Json-lib可以将Java对象转成json格式的字符串，也可以将Java对象转换成xml格式的文档，同样可以将json字符串转换成Java对象或是将xml字符串转换成Java对象。

一、准备工作

1、首先要去官方下载json-lib工具包

下载地址：

http://sourceforge.net/projects/json-lib/files/json-lib/json-lib-2.4/

目前最新的是2.4的版本，本示例中使用的是v2.3；json-lib还需要以下依赖包：

jakarta commons-lang 2.5

jakarta commons-beanutils 1.8.0

jakarta commons-collections 3.2.1

jakarta commons-logging 1.1.1

ezmorph 1.0.6

官方网址：http://json-lib.sourceforge.net/

然后在工程中添加如下jar包：

clip_image002

当然你也可以用2.4的json-lib库

你可以在这里看看官方提供的示例：

http://json-lib.sourceforge.net/usage.html

由于本次介绍的示例需要junit工具，所以你还需要添加junit的jar文件，版本是4.8.2版本的，下载地址：https://github.com/KentBeck/junit/downloads

如果你还不了解JSON是什么？那么你应该可以看看http://www.json.org/json-zh.html

2、要转换的JavaBean的代码如下：

package com.hoo.entity;

public class Student {

private int id;

private String name;

private String email;

private String address;

private Birthday birthday;

//setter、getter

public String toString() {

return this.name + "#" + this.id + "#" + this.address + "#" + this.birthday + "#" + this.email;

}

Birthday.java

package com.hoo.entity;

public class Birthday {

private String birthday;

public Birthday(String birthday) {

super();

this.birthday = birthday;

}

//setter、getter

public Birthday() {}

@Override

public String toString() {

return this.birthday;

}

注意，上面的getter、setter方法省略了，自己构建下。

3、新建JsonlibTest测试类，基本代码如下：

package com.hoo.test;

import java.lang.reflect.InvocationTargetException;

import java.util.ArrayList;

import java.util.Collection;

import java.util.Date;

import java.util.HashMap;

import java.util.Iterator;

import java.util.List;

import java.util.Map;

import java.util.Set;

import net.sf.json.JSON;

import net.sf.json.JSONArray;

import net.sf.json.JSONFunction;

import net.sf.json.JSONObject;

import net.sf.json.JSONSerializer;

import net.sf.json.JsonConfig;

import net.sf.json.processors.JsonValueProcessor;

import net.sf.json.util.PropertyFilter;

import net.sf.json.xml.XMLSerializer;

import org.apache.commons.beanutils.PropertyUtils;

import org.junit.After;

import org.junit.Before;

import org.junit.Test;

import com.hoo.entity.Birthday;

import com.hoo.entity.Student;

/**

* function: 用json-lib转换java对象到JSON字符串

* 读取json字符串到java对象，序列化jsonObject到xml

* json-lib-version: json-lib-2.3-jdk15.jar

* 依赖包:

* commons-beanutils.jar

* commons-collections-3.2.jar

* ezmorph-1.0.3.jar

* commons-lang.jar

* commons-logging.jar

* @author hoojo

* @createDate Nov 28, 2010 2:28:39 PM

* @file JsonlibTest.java

* @package com.hoo.test

* @project WebHttpUtils

* @blog http://blog.csdn.net/IBM_hoojo

* @email [email protected]

* @version 1.0

@SuppressWarnings({ "deprecation", "unchecked" })

public class JsonlibTest {

private JSONArray jsonArray = null;

private JSONObject jsonObject = null;

private Student bean = null;

@Before

public void init() {

jsonArray = new JSONArray();

jsonObject = new JSONObject();

bean = new Student();

bean.setAddress("address");

bean.setEmail("email");

bean.setId(1);

bean.setName("haha");

Birthday day = new Birthday();

day.setBirthday("2010-11-22");

bean.setBirthday(day);

}

@After

public void destory() {

jsonArray = null;

jsonObject = null;

bean = null;

System.gc();

}

public final void fail(String string) {

System.out.println(string);

}

public final void failRed(String string) {

System.err.println(string);

}

上面的init会在每个方法之前运行，destory会在每个方法完成后执行。分别用到了junit的@Before、@After注解，如果你对junit的这些注解不是很了解，可以看看junit官方的测试用例的example和doc；

JSONObject是将Java对象转换成一个json的Object形式，JSONArray是将一个Java对象转换成json的Array格式。

那什么是json的Object形式、Array形式？

用通俗易懂的方法将，所谓的json的Object形式就是一个花括号里面存放的如JavaMap的键值对，如：{name:’hoojo’, age: 24}；

那么json的Array形式呢？

就是中括号，括起来的数组。如：[ ‘json’, true, 22]；

如果你还想了解更多json方面的知识，请看：http://www.json.org/json-zh.html

除了上面的JSONArray、JSONObject可以将Java对象转换成JSON或是相反，将JSON字符串转换成Java对象，还有一个对象也可以完成上面的功能，它就是JSONSerializer；下面我们就来看看它们是怎么玩转Java对象和JSON的。

二、 Java对象序列化成JSON对象

1、将JavaObject转换吃JSON字符串

在JsonlibTest中添加如下代码：

/*=========================Java Object >>>> JSON String ===========================*/

/**

* function:转Java Bean对象到JSON

* @author hoojo

* @createDate Nov 28, 2010 2:35:54 PM

@Test

public void writeEntity2JSON() {

fail("==============Java Bean >>> JSON Object==================");

fail(JSONObject.fromObject(bean).toString());

fail("==============Java Bean >>> JSON Array==================");

fail(JSONArray.fromObject(bean).toString());//array会在最外层套上[]

fail("==============Java Bean >>> JSON Object ==================");

fail(JSONSerializer.toJSON(bean).toString());

fail("========================JsonConfig========================");

JsonConfig jsonConfig = new JsonConfig();

jsonConfig.registerJsonValueProcessor(Birthday.class, new JsonValueProcessor() {

public Object processArrayValue(Object value, JsonConfig jsonConfig) {

if (value == null) {

return new Date();

}

return value;

}

public Object processObjectValue(String key, Object value, JsonConfig jsonConfig) {

fail("key:" + key);

return value + "##修改过的日期";

}

});

jsonObject = JSONObject.fromObject(bean, jsonConfig);

fail(jsonObject.toString());

Student student = (Student) JSONObject.toBean(jsonObject, Student.class);

fail(jsonObject.getString("birthday"));

fail(student.toString());

fail("#####################JsonPropertyFilter############################");

jsonConfig.setJsonPropertyFilter(new PropertyFilter() {

public boolean apply(Object source, String name, Object value) {

fail(source + "%%%" + name + "--" + value);

//忽略birthday属性

if (value != null && Birthday.class.isAssignableFrom(value.getClass())) {

return true;

}

return false;

}

});

fail(JSONObject.fromObject(bean, jsonConfig).toString());

fail("#################JavaPropertyFilter##################");

jsonConfig.setRootClass(Student.class);

jsonConfig.setJavaPropertyFilter(new PropertyFilter() {

public boolean apply(Object source, String name, Object value) {

fail(name + "@" + value + "#" + source);

if ("id".equals(name) || "email".equals(name)) {

value = name + "@@";

return true;

}

return false;

}

});

//jsonObject = JSONObject.fromObject(bean, jsonConfig);

//student = (Student) JSONObject.toBean(jsonObject, Student.class);

//fail(student.toString());

student = (Student) JSONObject.toBean(jsonObject, jsonConfig);

fail("Student:" + student.toString());

}

fromObject将Java对象转换成json字符串，toBean将json对象转换成Java对象；

上面方法值得注意的是使用了JsonConfig这个对象，这个对象可以在序列化的时候对JavaObject的数据进行处理、过滤等

上面的jsonConfig的registerJsonValueProcessor方法可以完成对象值的处理和修改，比如处理生日为null时，给一个特定的值。同样setJsonPropertyFilter和setJavaPropertyFilter都是完成对转换后的值的处理。

运行上面的代码可以在控制台看到如下结果：

==============Java Bean >>> JSON Object==================

{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"haha"}

==============Java Bean >>> JSON Array==================

[{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"haha"}]

==============Java Bean >>> JSON Object ==================

{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"haha"}

========================JsonConfig========================

key:birthday

{"address":"address","birthday":"2010-11-22##修改过的日期","email":"email","id":1,"name":"haha"}

2010-11-22##修改过的日期

haha#1#address#null#email

#####################JsonPropertyFilter############################

haha#1#address#2010-11-22#email%%%address--address

haha#1#address#2010-11-22#email%%%birthday--2010-11-22

haha#1#address#2010-11-22#email%%%email--email

haha#1#address#2010-11-22#email%%%id--1

haha#1#address#2010-11-22#email%%%name--haha

{"address":"address","email":"email","id":1,"name":"haha"}

#################JavaPropertyFilter##################

address@address#null#0#null#null#null

birthday@2010-11-22##修改过的日期#null#0#address#null#null

email@email#null#0#address#null#null

id@1#null#0#address#null#null

name@haha#null#0#address#null#null

Student:haha#0#address#null#null

2、将JavaList集合转换吃JSON字符串

/**

* function:转换Java List集合到JSON

* @author hoojo

* @createDate Nov 28, 2010 2:36:15 PM

@Test

public void writeList2JSON() {

fail("==============Java List >>> JSON Array==================");

List<Student> stu = new ArrayList<Student>();

stu.add(bean);

bean.setName("jack");

stu.add(bean);

fail(JSONArray.fromObject(stu).toString());

fail(JSONSerializer.toJSON(stu).toString());

}

运行此方法后，可以看到控制台输出：

==============Java List >>> JSON Array==================

[{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},

{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"}]

[{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},

{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"}]

如果你是转换List集合，一定得用JSONArray或是JSONSrializer提供的序列化方法。如果你用JSONObject.fromObject方法转换List会出现异常，通常使用JSONSrializer这个JSON序列化的方法，它会自动识别你传递的对象的类型，然后转换成相应的JSON字符串。

3、将Map集合转换成JSON对象

/**

* function:转Java Map对象到JSON

* @author hoojo

* @createDate Nov 28, 2010 2:37:35 PM

@Test

public void writeMap2JSON() {

Map<String, Object> map = new HashMap<String, Object>();

map.put("A", bean);

bean.setName("jack");

map.put("B", bean);

map.put("name", "json");

map.put("bool", Boolean.TRUE);

map.put("int", new Integer(1));

map.put("arr", new String[] { "a", "b" });

map.put("func", "function(i){ return this.arr[i]; }");

fail("==============Java Map >>> JSON Object==================");

fail(JSONObject.fromObject(map).toString());

fail("==============Java Map >>> JSON Array ==================");

fail(JSONArray.fromObject(map).toString());

fail("==============Java Map >>> JSON Object==================");

fail(JSONSerializer.toJSON(map).toString());

}

上面的Map集合有JavaBean、String、Boolean、Integer、以及Array和js的function函数的字符串。

运行上面的程序，结果如下：

==============Java Map >>> JSON Object==================

{"arr":["a","b"],"A":{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},"int":1,

"B":{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},"name":"json",

"func":function(i){ return this.arr[i]; },"bool":true}

==============Java Map >>> JSON Array ==================

[{"arr":["a","b"],"A":{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},"int":1,

"B":{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},"name":"json",

"func":function(i){ return this.arr[i]; },"bool":true}]

==============Java Map >>> JSON Object==================

{"arr":["a","b"],"A":{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},"int":1,

"B":{"address":"address","birthday":{"birthday":"2010-11-22"},"email":"email","id":1,"name":"jack"},"name":"json",

"func":function(i){ return this.arr[i]; },"bool":true}

4、将更多类型转换成JSON

/**

* function: 转换更多数组类型到JSON

* @author hoojo

* @createDate Nov 28, 2010 2:39:19 PM

@Test

public void writeObject2JSON() {

String[] sa = {"a", "b", "c"};

fail("==============Java StringArray >>> JSON Array ==================");

fail(JSONArray.fromObject(sa).toString());

fail(JSONSerializer.toJSON(sa).toString());

fail("==============Java boolean Array >>> JSON Array ==================");

boolean[] bo = { true, false, true };

fail(JSONArray.fromObject(bo).toString());

fail(JSONSerializer.toJSON(bo).toString());

Object[] o = { 1, "a", true, 'A', sa, bo };

fail("==============Java Object Array >>> JSON Array ==================");

fail(JSONArray.fromObject(o).toString());

fail(JSONSerializer.toJSON(o).toString());

fail("==============Java String >>> JSON ==================");

fail(JSONArray.fromObject("['json','is','easy']").toString());

fail(JSONObject.fromObject("{'json':'is easy'}").toString());

fail(JSONSerializer.toJSON("['json','is','easy']").toString());

fail("==============Java JSONObject >>> JSON ==================");

jsonObject = new JSONObject()

.element("string", "JSON")

.element("integer", "1")

.element("double", "2.0")

.element("boolean", "true");

fail(JSONSerializer.toJSON(jsonObject).toString());

fail("==============Java JSONArray >>> JSON ==================");

jsonArray = new JSONArray()

.element( "JSON" )

.element( "1" )

.element( "2.0" )

.element( "true" );

fail(JSONSerializer.toJSON(jsonArray).toString());

fail("==============Java JSONArray JsonConfig#setArrayMode >>> JSON ==================");

List input = new ArrayList();

input.add("JSON");

input.add("1");

input.add("2.0");

input.add("true");

JSONArray jsonArray = (JSONArray) JSONSerializer.toJSON( input );

JsonConfig jsonConfig = new JsonConfig();

jsonConfig.setArrayMode( JsonConfig.MODE_OBJECT_ARRAY );

Object[] output = (Object[]) JSONSerializer.toJava(jsonArray, jsonConfig);

System.out.println(output[0]);

fail("==============Java JSONFunction >>> JSON ==================");

String str = "{'func': function( param ){ doSomethingWithParam(param); }}";

JSONObject jsonObject = (JSONObject) JSONSerializer.toJSON(str);

JSONFunction func = (JSONFunction) jsonObject.get("func");

fail(func.getParams()[0]);

fail(func.getText() );

}

运行后结果如下：

==============Java StringArray >>> JSON Array ==================

["a","b","c"]

==============Java boolean Array >>> JSON Array ==================

[true,false,true]

==============Java Object Array >>> JSON Array ==================

[1,"a",true,"A",["a","b","c"],[true,false,true]]

==============Java String >>> JSON ==================

["json","is","easy"]

{"json":"is easy"}

["json","is","easy"]

==============Java JSONObject >>> JSON ==================

{"string":"JSON","integer":"1","double":"2.0","boolean":"true"}

==============Java JSONArray >>> JSON ==================

["JSON","1","2.0","true"]

==============Java JSONArray JsonConfig#setArrayMode >>> JSON ==================

JSON

==============Java JSONFunction >>> JSON ==================

param

doSomethingWithParam(param);

这里还有一个JSONFunction的对象，可以转换JavaScript的function。可以获取方法参数和方法体。同时，还可以用JSONObject、JSONArray构建Java对象，完成Java对象到JSON字符串的转换。

三、 JSON对象反序列化成Java对象

1、将json字符串转成Java对象

private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"}," +

"\"email\":\"[email protected]\",\"id\":22,\"name\":\"tom\"}";

/**

* function:将json字符串转化为java对象

* @author hoojo

* @createDate Nov 28, 2010 3:01:16 PM

@Test

public void readJSON2Bean() {

fail("==============JSON Object String >>> Java Bean ==================");

jsonObject = JSONObject.fromObject(json);

Student stu = (Student) JSONObject.toBean(jsonObject, Student.class);

fail(stu.toString());

}

运行后，结果如下：

==============JSON Object String >>> Java Bean ==================

tom#22#chian#2010-11-22#[email protected]

2、将json字符串转换成动态Java对象(MorphDynaBean)

private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+

"\"email\":\"[email protected]\",\"id\":22,\"name\":\"tom\"}";

@Test

public void readJSON2DynaBean() {

try {

fail("==============JSON Object String >>> Java MorphDynaBean ==================");

JSON jo = JSONSerializer.toJSON(json);

Object o = JSONSerializer.toJava(jo);//MorphDynaBean

fail(PropertyUtils.getProperty(o, "address").toString());

jsonObject = JSONObject.fromObject(json);

fail(jsonObject.getString("email"));

o = JSONSerializer.toJava(jsonObject);//MorphDynaBean

fail(PropertyUtils.getProperty(o, "name").toString());

} catch (IllegalAccessException e) {

e.printStackTrace();

} catch (InvocationTargetException e) {

e.printStackTrace();

} catch (NoSuchMethodException e) {

e.printStackTrace();

}

转换后的对象Object是一个MorphDynaBean的动态JavaBean，通过PropertyUtils可以获得指定的属性的值。

运行后结果如下：

==============JSON Object String >>> Java MorphDynaBean =============

chian

[email protected]

tom

3、将json字符串转成Java的Array数组

private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+

"\"email\":\"[email protected]\",\"id\":22,\"name\":\"tom\"}";

@Test

public void readJSON2Array() {

try {

fail("==============JSON Arry String >>> Java Array ==================");

json = "[" + json + "]";

jsonArray = JSONArray.fromObject(json);

fail("#%%%" + jsonArray.get(0).toString());

Object[] os = jsonArray.toArray();

System.out.println(os.length);

fail(JSONArray.fromObject(json).join(""));

fail(os[0].toString());

Student[] stus = (Student[]) JSONArray.toArray(jsonArray, Student.class);

System.out.println(stus.length);

System.out.println(stus[0]);

} catch (Exception e) {

e.printStackTrace();

}

运行的结果如下：

==============JSON Arry String >>> Java Array ==================

#%%%{"address":"chian","birthday":{"birthday":"2010-11-22"},"email":"[email protected]","id":22,"name":"tom"}

{"address":"chian","birthday":{"birthday":"2010-11-22"},"email":"[email protected]","id":22,"name":"tom"}

tom#22#chian#2010-11-22#[email protected]

4、将JSON字符串转成Java的List集合

private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+

"\"email\":\"[email protected]\",\"id\":22,\"name\":\"tom\"}";

@Test

public void readJSON2List() {

try {

fail("==============JSON Arry String >>> Java List ==================");

json = "[" + json + "]";

jsonArray = JSONArray.fromObject(json);

List<Student> list = JSONArray.toList(jsonArray, Student.class);

System.out.println(list.size());

System.out.println(list.get(0));

list = JSONArray.toList(jsonArray);

System.out.println(list.size());

System.out.println(list.get(0));//MorphDynaBean

} catch (Exception e) {

e.printStackTrace();

}

运行后结果如下：

==============JSON Arry String >>> Java List ==================

tom#22#chian#2010-11-22#[email protected]

net.sf.ezmorph.bean.MorphDynaBean@141b571[

{id=22, birthday=net.sf.ezmorph.bean.MorphDynaBean@b23210[

{birthday=2010-11-22}

], address=chian, [email protected], name=tom}

]

5、将json字符串转换成Collection接口

private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+

"\"email\":\"[email protected]\",\"id\":22,\"name\":\"tom\"}";

@Test

public void readJSON2Collection() {

try {

fail("==============JSON Arry String >>> Java Collection ==================");

json = "[" + json + "]";

jsonArray = JSONArray.fromObject(json);

Collection<Student> con = JSONArray.toCollection(jsonArray, Student.class);

System.out.println(con.size());

Object[] stt = con.toArray();

System.out.println(stt.length);

fail(stt[0].toString());

} catch (Exception e) {

e.printStackTrace();

}

刚才上面的将json转换成list提示该方法过时，这里有toCollection，可以用此方法代替toList方法；运行后结果如下：

==============JSON Arry String >>> Java Collection ==================

tom#22#chian#2010-11-22#[email protected]

6、将json字符串转换成Map集合

@Test

public void readJSON2Map() {

try {

fail("==============JSON Arry String >>> Java Map ==================");

json = "{\"arr\":[\"a\",\"b\"],\"A\":{\"address\":\"address\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+

"\"email\":\"email\",\"id\":1,\"name\":\"jack\"},\"int\":1,"+

"\"B\":{\"address\":\"address\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+

"\"email\":\"email\",\"id\":1,\"name\":\"jack\"},\"name\":\"json\",\"bool\":true}";

jsonObject = JSONObject.fromObject(json);

Map<String, Class<?>> clazzMap = new HashMap<String, Class<?>>();

clazzMap.put("arr", String[].class);

clazzMap.put("A", Student.class);

clazzMap.put("B", Student.class);

Map<String, ?> mapBean = (Map) JSONObject.toBean(jsonObject, Map.class, clazzMap);

System.out.println(mapBean);

Set<String> set = mapBean.keySet();

Iterator<String> iter = set.iterator();

while (iter.hasNext()) {

String key = iter.next();

fail(key + ":" + mapBean.get(key).toString());

}

} catch (Exception e) {

e.printStackTrace();

}

运行后结果如下：

==============JSON Arry String >>> Java Map ==================

{A=jack#1#address#2010-11-22#email, arr=[a, b], B=jack#1#address#2010-11-22#email, int=1, name=json, bool=true}

A:jack#1#address#2010-11-22#email

arr:[a, b]

B:jack#1#address#2010-11-22#email

int:1

name:json

bool:true

四、 JSON-lib对XML的支持

1、将Java对象到XML

/*============================Java Object >>>>> XML ==========================*/

/**

* function: 转换Java对象到XML

* 需要额外的jar包：xom.jar

* @author hoojo

* @createDate Nov 28, 2010 2:39:55 PM

@Test

public void writeObject2XML() {

XMLSerializer xmlSerializer = new XMLSerializer();

fail("==============Java String Array >>> XML ==================");

//xmlSerializer.setElementName("bean");

fail(xmlSerializer.write(JSONArray.fromObject(bean)));

String[] sa = {"a", "b", "c"};

fail("==============Java String Array >>> XML ==================");

fail(xmlSerializer.write(JSONArray.fromObject(sa)));

fail("==============Java boolean Array >>> XML ==================");

boolean[] bo = { true, false, true };

fail(xmlSerializer.write(JSONArray.fromObject(bo)));

fail(xmlSerializer.write(JSONSerializer.toJSON(bo)));

Object[] o = { 1, "a", true, 'A', sa, bo };

fail("==============Java Object Array >>> JSON Array ==================");

fail(xmlSerializer.write(JSONArray.fromObject(o)));

fail(xmlSerializer.write(JSONSerializer.toJSON(o)));

fail("==============Java String >>> JSON ==================");

fail(xmlSerializer.write(JSONArray.fromObject("['json','is','easy']")).toString());

fail(xmlSerializer.write(JSONObject.fromObject("{'json':'is easy'}")).toString());

fail(xmlSerializer.write(JSONSerializer.toJSON("['json','is','easy']")).toString());

}

主要运用的是XMLSerializer的write方法，这个方法可以完成java对象到xml的转换，不过你很容易就可以看到这个xml序列化对象，需要先将java对象转成json对象，然后再将json转换吃xml文档。

运行后结果如下：

==============Java String Array >>> XML ==================