你必须掌握的Java基础：JSON解析工具-json-lib
一、简介
json-lib是一个Java类库，提供将Java对象，包括beans,maps,collections,java arrays和xml等转换成JSON,或者反向转换的功能。
二、准备
在使用json-lib之前，我们应该到官方网址下载如下包：
-
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
并将这些jar包引入到Eclipse项目当中，即可调用。
三、讲解
在进行下面的代码演示之前，我们先将几个基本的类介绍一下：
MyBean类：
public class MyBean {
private String id = null;
private String name = null;
ﾠ ﾠ private Date date = null;
ﾠ ﾠ private List cardNum = null;
private String[] cardType = {"身份证", "银行卡" , "公车卡"};
ﾠ ﾠ public String getId() {
return id;
}
ﾠ ﾠ public void setId(String id) {
this.id = id;
}
public String getName() {
return name;
}
ﾠ ﾠ public void setName(String name) {
this.name = name;
}
ﾠ ﾠ public Date getDate() {
return date;
}
ﾠ ﾠ public void setDate(Date date) {
this.date = date;
}
ﾠ ﾠ public List getCardNum() {
ﾠ ﾠ ﾠ ﾠ return cardNum;
}
ﾠ ﾠ public void setCardNum(List cardNum) {
ﾠ ﾠ ﾠ ﾠ this.cardNum = cardNum;
}
ﾠ ﾠ public String[] getCardType() {
ﾠ ﾠ ﾠ ﾠ return cardType;
}
ﾠ ﾠ public void setCardType(String[] cardType) {
this.cardType = cardType;
}
}
Person类：
public class Person {
private String name = null;
public Person(){
}
public Person(String name){
this.name = name;
}
ﾠ ﾠ public String getName() {
return name;
}
ﾠ ﾠ public void setName(String name) {
this.name = name;
}
}
MyBeanWithPerson类：
public class MyBeanWithPerson {
private List<Person> list = null;
ﾠ ﾠ private Map<String,Person> map = null;
ﾠ ﾠ public List getList() {
return list;
}
ﾠ ﾠ public void setList(List list) {
this.list = list;
}
ﾠ ﾠ public Map getMap() {
return map;
}
ﾠ ﾠ public void setMap(Map map) {
this.map = map;
}
}
1.将json字符串转换成JSON，根据情况用JSONArray或JSONObject
public static void testJsonStrToJSON() {
JSONArray jsonArray = JSONArray.fromObject("[\"json\",\"is\",\"easy\"]");
ﾠ ﾠ System.out.println(jsonArray);
}
2.将Java Bean转换成JSON对象
public static void testBeadToJSON() {
MyBean bean = new MyBean();
bean.setId("001");
bean.setName("银行卡");
bean.setDate(new Date());
ﾠ ﾠ List cardNum = new ArrayList();
cardNum.add("农行");
cardNum.add("工行");
cardNum.add("建行");
cardNum.add(new Person("test"));
ﾠ ﾠ bean.setCardNum(cardNum);
ﾠ ﾠ JSONObject jsonObject = JSONObject.fromObject(bean);
ﾠ ﾠ System.out.println(jsonObject);
}
3.将一般的数组转换成JSON
public static void testArrayToJSON() {
boolean[] boolArray = new boolean[] { true, false, true };
JSONArray jsonArray = JSONArray.fromObject(boolArray);
System.out.println(jsonArray);
}
4.将Collection对象转换成JSON
public static void testListToJSON() {
List list = new ArrayList();
list.add("first");
list.add("second");
ﾠ ﾠ JSONArray jsonArray = JSONArray.fromObject(list);
ﾠ ﾠ System.out.println(jsonArray);
}
5.将Map转换成JSON
public static void testMapToJSON() {
Map map = new HashMap();
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]; }");
ﾠ ﾠ JSONObject jsonObject = JSONObject.fromObject(map);
ﾠ ﾠ System.out.println(jsonObject);
}
6.将普通类型的JSON字符串转换成JSON
public static void testJSONToObject() throws Exception {
// 将JSon字符串转换成JsonObject对象
String json = "{name=\"json\",bool:true,int:1,double:2.2,func:\"function(a){ return a; }\",array:[1,2]}";
JSONObject jsonObject = JSONObject.fromObject(json);
System.out.println(jsonObject);
// 将JsonObject对象转换成JavaBean对象
Object bean = JSONObject.toBean(jsonObject);
ﾠ ﾠ System.out.println(PropertyUtils.getProperty(bean, "name"));
ﾠ ﾠ System.out.println(PropertyUtils.getProperty(bean, "bool"));
ﾠ ﾠ System.out.println(PropertyUtils.getProperty(bean, "int"));
System.out.println(PropertyUtils.getProperty(bean, "double"));
ﾠ ﾠ System.out.println(PropertyUtils.getProperty(bean, "func"));
ﾠ ﾠ System.out.println(PropertyUtils.getProperty(bean, "array"));
ﾠ ﾠ List arrayList = (List) JSONArray.toCollection(jsonObject.getJSONArray("array"));
ﾠ ﾠ for (Object object : arrayList) {
System.out.println(object);
}
}
7.将复合类型的JSON字符串转换成复合对象，包含List
public static void testJSONToBeanHavaList() {
String json = "{list:[{name:\"test1\"},{name:\"test2\"}]}";
Map classMap = new HashMap();
classMap.put("list", Person.class);
ﾠ ﾠ MyBeanWithPerson diyBean = (MyBeanWithPerson) JSONObject.toBean(
ﾠ ﾠ JSONObject.fromObject(json), MyBeanWithPerson.class, classMap);
ﾠ ﾠ System.out.println(diyBean);
ﾠ ﾠ List list = diyBean.getList();
for (Object o : list) {
if (o instanceof Person) {
Person p = (Person) o;
ﾠ ﾠ ﾠ ﾠ ﾠ ﾠ System.out.println(p.getName());
}
}
}
8.将复合类型的JSON字符串转换成复合对象，包含Map
public static void testJSONToBeanHavaMap() {
// 把Map看成一个对象
String json = "{list:[{name:\"test1\"},{name:\"test2\"}],map:{test1:{name:\"test1\"},test2:{name:\"test2\"}}}";
Map classMap = new HashMap();
classMap.put("list", Person.class);
classMap.put("map", Map.class);
// 使用暗示，直接将json解析为指定自定义对象，其中List完全解析,Map没有完全解析
MyBeanWithPerson diyBean =(MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json), MyBeanWithPerson.class, classMap);
ﾠ ﾠ System.out.println(diyBean);
ﾠ ﾠ System.out.println("do the list release");
List<Person> list = diyBean.getList();
for (Person o : list) {
Person p = (Person) o;
ﾠ ﾠ ﾠ ﾠ System.out.println(p.getName());
}
ﾠ ﾠ System.out.println("do the map release");
// 先往注册器中注册变换器，需要用到ezmorph包中的类
MorpherRegistry morpherRegistry = JSONUtils.getMorpherRegistry();
ﾠ ﾠ Morpher dynaMorpher = new BeanMorpher(Person.class, morpherRegistry);
morpherRegistry.registerMorpher(dynaMorpher);
ﾠ ﾠ Map map = diyBean.getMap();
//这里的map没进行类型暗示，故按默认的，里面存的为net.sf.ezmorph.bean.MorphDynaBean类型的对象
ﾠ ﾠ System.out.println(map);
ﾠ ﾠ ﾠList<Person> output = new ArrayList();
ﾠ ﾠ for (Iterator i = map.values().iterator(); i.hasNext();) {
// 使用注册器对指定DynaBean进行对象变换
output.add((Person) morpherRegistry.morph(Person.class, i.next()));
}
for (Person p : output) {
ﾠ ﾠ ﾠ ﾠ System.out.println(p.getName());
}
}