JSON解析类库之JSON-lib --- JSON-lib类库学习, 生成与解析json数据, json字符串与Java对象互转
谭梓
JSON解析类库之JSON-lib --- JSON-lib类库学习, 生成与解析json数据, json字符串与Java对象互转
前言
JSON-lib是java项目开发中，经常用到的json数据解析与生成的Java类库，历史比较悠久。不过已经N年没有更新了，且性能效率实在是很一般，在互联网项目中是坚决不建议使用这个类库的。该类库依赖的jar包就有5个。但是经常在一些老项目维护中看到JSON-lib的使用。
一、什么是 JSON
JSON（JavaScript Object Notation）（官网网站：http://www.json.org/）是 一种轻量级的数据交换格式。 易于人阅读和编写。同时也易于机器解析和生成。它基于 JavaScript Programming Language, Standard ECMA-262 3rd Edition - December 1999 的一个子集。 JSON 采用完全独立于语言的文本格式，但是也使用了类似于 C 语言家族的习惯（包括C, C++, C#, Java, JavaScript, Perl, Python等）。 这些特性使 JSON 成为理想的数据交换语言。
二、JSON 的两种结构
1、“名称/值”对的集合（A collection of name/value pairs）。不同的语言中，它被理解为对象（object），纪录（record），结构（struct），字典（dictionary），哈希表 （hash table），有键列表（keyed list），或者关联数组 （associative array）。 在 Java 语言中，我们可以将它理解成 HashMap或者对象。
对象是一个无序的"'名称/值'对"集合。一个对象以"{"（左括号）开始，"}"（右括号）结束。每个“名称”后跟一 个":"（冒号）；"'名称/值' 对"之间使用","（逗号）分隔。
示例：var json = {"name":"Jack","age":90,"Marray":true};
三、JSON-lib
Json-lib 是一个 Java 类库（官网：http://json-lib.sourceforge.net/）可以实现如下功能：
1、转换 JavaBean, Map, Collection, Java Array 和 XML 成为 JSON格式数据。
2、转换 JSON 格式数据成为 JavaBean对象、Map、Collection、List、Array等。
Json-lib可以将Java对象转成JSON格式的字符串，同样可以将JSON字符串转换成Java对象。
Json-lib 需要的 jar 包:
官方下载地址：http://sourceforge.net/projects/json-lib/files/json-lib/json-lib-2.4/ 【包含源码下载】
下载地址2：http://www.java2s.com/Code/Jar/j/Downloadjsonlib24jdk15sourcesjar.htm 【json-lib源码下载】
csdn下载地址：http://download.csdn.net/detail/chenchunlin526/9810451 【全部jar包，还包括一个源码包】
commons-beanutils-1.8.3.jar 【依赖包】
commons-collections-3.2.1.jar 【依赖包】
commons-lang-2.6.jar 【依赖包】
commons-logging-1.1.1.jar 【依赖包】
ezmorph-1.0.6.jar 【依赖包】
json-lib-2.4-jdk15.jar （最核心包）
四、JSON-lib 的使用
1. 将 Java数组/集合 序列化成Json对象。使用 JSONArray 可以序列化数组类型：
Java Array ---》JSON Array
Java List ---》JSON Array
Java Set ---》JSON Array
import java.util.ArrayList;
import java.util.HashSet;
import java.util.List;
import java.util.Set;
import net.sf.json.JSONArray;
public class JsonLib {
public static void main(String[] args) {
/**
* 将字符串数组解析成JSON对象
*/
String[] str = { "Jack", "Tom", "90", "true" }; //字符串数组
JSONArray json = JSONArray.fromObject(str); //将数组序列化成json对象
System.err.println(json); //可以先将JSONArray类型的json对象转换成String类型再输出
// System.out.println(json.toString());
// ["Jack","Tom","90","true"]
/**
* 对像数组，注意数字和布而值
*/
Object[] obj = { "北京", "上海", 89, true, 90.87 };
JSONArray json = JSONArray.fromObject(obj);
System.err.println(json);
// ["北京","上海",89,true,90.87]
/**
* 使用集合类List<T>
*/
List<String> list = new ArrayList<String>();
list.add("Jack");
list.add("Rose");
JSONArray json = JSONArray.fromObject(list);
System.err.println(json);
// ["Jack","Rose"]
/**
* 使用 set 集
*/
Set<Object> set = new HashSet<Object>();
set.add("Hello");
set.add(true);
set.add(99);
JSONArray json = JSONArray.fromObject(set);
System.err.println(json);
// [99,true,"Hello"]
}
}
["Jack","Tom","90","true"]
["北京","上海",89,true,90.87]
["Jack","Rose"]
[99,true,"Hello"]2. 将 JavaBean/Map 序列化成 JSON 对象。 使用JSONObject 解析：
JavaBean ---》JSON Object
Java Map ---》JSON Object
import java.util.HashMap;
import java.util.Map;
import net.sf.json.JSONObject;
public class JsonLib {
@SuppressWarnings("static-access")
public static void main(String[] args) {
/**
* 解析Map/HashMap
*/
Map<String, Object> map = new HashMap<String, Object>();
map.put("name", "Tom");
map.put("age", 33);
JSONObject jsonObject = JSONObject.fromObject(map);
System.out.println(jsonObject);
//{"age":33,"name":"Tom"}
/**
* 解析 JavaBean
*/
Person person = new Person("A001", "Jack"); //初始化Person对象
JSONObject jsonObject = JSONObject.fromObject(person);
System.out.println(jsonObject);
//{"id":"A001","name":"Jack"}
/**
* 解析嵌套的对象 Map<String, Object>
*/
map.put("person", person);
JSONObject jsonObject = JSONObject.fromObject(map);
System.out.println(jsonObject);
// {"person":{"id":"A001","name":"Jack"},"age":33,"name":"Tom"}
}
}
{"age":33,"name":"Tom"}
{"id":"A001","name":"Jack"}
{"person":{"id":"A001","name":"Jack"},"age":33,"name":"Tom"}3. 使用 JsonConfig 过滤属性：适用于 JavaBean/Map
import net.sf.json.JSONObject;
import net.sf.json.JsonConfig;
public class JsonLib {
public static void main(String[] args) {
JsonConfig config = new JsonConfig();
config.setExcludes(new String[] { "name" }); //指定在转换时不包含哪些属性,此处排除name属性
Person person = new Person("A001", "Jack"); // 初始化Person对象
JSONObject jsonObject = JSONObject.fromObject(person, config); //在转换时传入之前的配置对象
System.out.println(jsonObject);
// {"id":"A001"}
}
}运行结果如下，在运行结果中我们可以看到 name 属性被过滤掉了：
{"id":"A001"}实例2（过滤Bean对象中字段为空，或字段的值为空的字段）
例：Test test = new Test();
test.setId("1");
test.setName("zhangsan");
jsonObject.fromobject(test).toString;
输出：{"id":"1","name":"zhangsan"}
假如不封装name属性，只封装id属性
Test test = new Test();
test.setId("1");
jsonObject.fromobject(test).toString;
输出：{"id":"1","name":""}
如果只输出：{"id":"1"} 这样的json字符，解决方法如下代码
public static void main(String[] args) {
Test t = new Test();
t.id = 10;
JsonConfig jsonConfig = new JsonConfig();
PropertyFilter filter = new PropertyFilter() {
public boolean apply(Object object, String fieldName, Object fieldValue) {
return null == fieldValue || "" == fieldValue;
}
};
jsonConfig.setJsonPropertyFilter(filter);
System.out.println(JSONObject.fromObject(t, jsonConfig).toString());
} 如果未给对象赋值用fieldName即可，如果值默认为空，设置fieldValue即可。
4. 将 JSON对象解析成（反序列化） Java Array：
JSON Array ---》Java Array
import java.util.Arrays;
import net.sf.json.JSONArray;
public class JsonLib {
public static void main(String[] args) {
JSONArray jsonArray = JSONArray.fromObject("[89,90,99]"); //创建JSONArray
Object array = JSONArray.toArray(jsonArray);//转换成Java Object
System.out.println(array);
// [Ljava.lang.Object;@1e5003f6
System.out.println(Arrays.asList((Object[]) array));
// [89, 90, 99]
}
}
[Ljava.lang.Object;@1e5003f6
[89, 90, 99]5. 将 Json对象解析成 JavaBean/Map（使用JSONObject的toBean()方法）：
JSON Object ---》JavaBean
JSON Object ---》Map
import java.util.Map;
import net.sf.json.JSONObject;
public class JsonLib {
@SuppressWarnings("unchecked")
public static void main(String[] args) {
/**
* 将 JSON 对象转换（解析）为 Map
*/
String str = "{\"name\":\"Tom\",\"age\":90}";
JSONObject jsonObject = JSONObject.fromObject(str);
Map<String, Object> map = (Map<String, Object>) JSONObject.toBean(jsonObject, Map.class);
System.out.println(map);
// {age=90, name=Tom}
/**
* 将 JSON对象转换（解析）为 JavaBean
*/
str = "{\"id\":\"A001\",\"name\":\"Jack\"}";
jsonObject = JSONObject.fromObject(str);
System.out.println(jsonObject); //JSONObject类型：{age=90, name=Tom}
Person person = (Person) JSONObject.toBean(jsonObject, Person.class);
System.out.println(person); //Person [id=A001, name=Jack]
}
}运行结果如下：
{age=90, name=Tom}
Person [id=A001, name=Jack]
在将 Json 形式的字符串转换为 JavaBean 的时候，需要注意 JavaBean 中必须有无参构造函数，否则会报如下找不到初始化方法的错误：
Exception in thread "main" net.sf.json.JSONException: java.lang.NoSuchMethodException: cn.sunzn.json.Person.<init>()
at net.sf.json.JSONObject.toBean(JSONObject.java:288)
at net.sf.json.JSONObject.toBean(JSONObject.java:233)
at cn.sunzn.json.JsonLib.main(JsonLib.java:23)
Caused by: java.lang.NoSuchMethodException: cn.sunzn.json.Person.<init>()
at java.lang.Class.getConstructor0(Unknown Source)
at java.lang.Class.getDeclaredConstructor(Unknown Source)
at net.sf.json.util.NewBeanInstanceStrategy$DefaultNewBeanInstanceStrategy.newInstance(NewBeanInstanceStrategy.java:55)
at net.sf.json.JSONObject.toBean(JSONObject.java:282)
... 2 more===================================================================================================================================
一、Java对象序列化成JSON对象
JSONObject是将Java对象转换（序列化）成一个JSON的Object形式，JSONArray是将一个Java对象转换（序列化）成JSON的Array格式。
◆那什么是JSON的Object形式、Array形式？--- 用通俗易懂的方法讲，所谓的JSON的Object形式，就是一个花括号里面存放的如Java Map的键值对，如：{name:’xiaoming’, 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（序列化）成JSON（或是相反：将JSON字符串转换（反序列化））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。
1、Java对象序列化成JSON对象【JSONSerializer、JsonConfig】
Java Bean ---》JSON Object
Java Bean ---》JSON Array
/**
* 转换（序列化）Java Bean对象到JSON
*/
@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());
}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Java Object的数据进行处理、过滤等。上面的jsonConfig的registerJsonValueProcessor方法可以完成对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Java List集合转换成JSON
Java List ---》JSON Array
/**
* 转换Java List集合到JSON
*/
@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());
}
==============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
Java Map ---》JSON Object
/**
* 转Java Map对象到JSON
*/
@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());
}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
**
* 转换更多数组类型到JSON
*/
@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"]
["a","b","c"]
==============Java boolean Array >>> JSON Array ==================
[true,false,true]
[true,false,true]
==============Java Object Array >>> JSON Array ==================
[1,"a",true,"A",["a","b","c"],[true,false,true]]
[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。
二、JSON对象反序列化成Java对象
1、 将json字符串转成Java对象（json字符串先转换成JSON对象，然后再转换成Java对象）
JSON Object ---》Java Bean
private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"}," +
"\"email\":\"email@123.com\",\"id\":22,\"name\":\"tom\"}";
/**
* 将json字符串转化为java对象
*/
@Test
public void readJSON2Bean() {
fail("==============JSON Object String >>> Java Bean ==================");
JSONObject jsonObject = JSONObject.fromObject(json);
Student stu = (Student) JSONObject.toBean(jsonObject, Student.class);
fail(stu.toString()); //tom#22#chian#2010-11-22#email@123.com
}====================JSON Object String >>> Java Bean ==================
tom#22#chian#2010-11-22#email@123.com实例2，把json对象转换成复杂bean对象
JSON Object ---》Java Bean
public class TranslateResult {
private String from; // 实际采用的源语言
private String to; // 实际采用的目标语言
private List<ResultPair> transResult; // 结果体
} public class ResultPair {
private String src; // 原文
private String dst; // 译文
}
StringBuffer sb = new StringBuffer();
String json = "{\"from\":\"en\",\"to\":\"zh\",\"transResult\":[{\"src\":\"hello\",\"dst\":\"您好\"},{\"src\":\"beautiful\",\"dst\":\"美女\"}]}";
JSONObject jsonObject = JSONObject.fromObject(json)
Map<String, Class<ResultPair>> clazzMap = new HashMap<String, Class<ResultPair>>();
map.put("transResult", ResultPair.class);
TranslateResult translateResult = (TranslateResult) JSONObject.toBean(jsonObject, TranslateResult.class, clazzMap);
List<ResultPair> list = translateResult.getTransResult();
for (ResultPair rp : list) {
sb.append(rp.getDst());
}
System.out.println(sb); // 输出：你好美女 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@123.com\",\"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()); //chian
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();
}
}运行后结果如下：
==============JSON Object String >>> Java MorphDynaBean =============
chian
email@123.com
tom3、将json字符串转成Java的Array数组
JSON Array ---》Java Array ---》Java bean
private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+
"\"email\":\"email@123.com\",\"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); // 1
fail(JSONArray.fromObject(json).join(""));
//{"address":"chian","birthday":{"birthday":"2010-11-22"},"email":"email@123.com","id":22,"name":"tom"}
fail(os[0].toString());
//{"address":"chian","birthday":{"birthday":"2010-11-22"},"email":"email@123.com","id":22,"name":"tom"}
Student[] stus = (Student[]) JSONArray.toArray(jsonArray, Student.class);
System.out.println(stus.length); //1
System.out.println(stus[0]); //tom#22#chian#2010-11-22#email@123.com
} catch (Exception e) {
e.printStackTrace();
}
}
==============JSON Arry String >>> Java Array ==================
#%%%{"address":"chian","birthday":{"birthday":"2010-11-22"},"email":"email@123.com","id":22,"name":"tom"}
1
{"address":"chian","birthday":{"birthday":"2010-11-22"},"email":"email@123.com","id":22,"name":"tom"}
{"address":"chian","birthday":{"birthday":"2010-11-22"},"email":"email@123.com","id":22,"name":"tom"}
1
tom#22#chian#2010-11-22#email@123.com4、将JSON字符串转成Java的List集合（已不推荐使用）
private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+
"\"email\":\"email@123.com\",\"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()); //1
System.out.println(list.get(0)); //tom#22#chian#2010-11-22#email@123.com
list = JSONArray.toList(jsonArray);
System.out.println(list.size()); // 1
System.out.println(list.get(0));//MorphDynaBean
//net.sf.ezmorph.bean.MorphDynaBean@141b571[{id=22,birthday=net.sf.ezmorph.bean.MorphDynaBean@b23210[{birthday=2010-11-22}], address=chian, email=email@123.com, name=tom}]
} catch (Exception e) {
e.printStackTrace();
}
}==============JSON Arry String >>> Java List ==================
1
tom#22#chian#2010-11-22#email@123.com
1
net.sf.ezmorph.bean.MorphDynaBean@141b571[
{id=22, birthday=net.sf.ezmorph.bean.MorphDynaBean@b23210[
{birthday=2010-11-22}
], address=chian, email=email@123.com, name=tom}
]5、将json字符串转换成Collection接口
JSON Array ---》Java Collection ---》Java Bean
private String json = "{\"address\":\"chian\",\"birthday\":{\"birthday\":\"2010-11-22\"},"+
"\"email\":\"email@123.com\",\"id\":22,\"name\":\"tom\"}";
@Test
public void readJSON2Collection() {
try {
fail("==============JSON Array String >>> Java Collection ==================");
json = "[" + json + "]";
jsonArray = JSONArray.fromObject(json);
Collection<Student> con = JSONArray.toCollection(jsonArray, Student.class);
System.out.println(con.size()); //1
Object[] stt = con.toArray();
System.out.println(stt.length); // 1
fail(stt[0].toString()); // tom#22#chian#2010-11-22#email@123.com
} catch (Exception e) {
e.printStackTrace();
}
}
==============JSON Arry String >>> Java Collection ==================
1
1
tom#22#chian#2010-11-22#email@123.com6、将json字符串转换成Map集合
复杂JSON类型---》Map
@Test
public void readJSON2Map() {
try {
fail("==============JSON Array 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); //关键代码
System.out.println(mapBean);
// {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}
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();
}
}
==============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
题外话：json-lib已经停止更新了（jdk1.5之后就没有更新过了），而且他的相关依赖包比较多（有5个依赖包，1个核心包），所以在新的项目开发中是不建议使用的，尤其是新的互联网项目中最好别用这个库，主要是他的性能比较差、速度慢。但是在一些需求比较简单的项目中还是可以用的，笔者的公司的很多老项目也在用。其实他的api方法还是比较好用的，也比较直观，易于理解。
目前，其他一些主流JSON库的性能已远远超过他。主流的优秀json解析库有：
1、Jackson（SpringMVC框架官方默认的json解析包，功能强大，性能优秀，不过api不怎么直观）
2、Gson（google公司开的，性能优秀，稳定性好）
3、Fastjson（阿里巴巴开发的，号称目前解析速度的最快的json库，api使用简单，易上手，性能好）等。
上面这三个库才是目前Java领域json解析库中，最牛B的三个库。排在第一梯队，性能不相上下。接下来的博文系列会分别讲解这三个库的使用方法。
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