Java转json
一、json介绍
1、 作用：JSON(JavaScript Object Notation) 是一种轻量级的数据交换格式，是存储和交换文本信息的语法。
2、json以key-value的格式书写，数据间以“，”分开，有两种数据结构：
对象：“{}”括起来的内容
数组：“[]”括起来的内容
如：{
"people":[ {"firstName":"Brett","lastName":"McLaughlin","email":"aaaa"}, {"firstName":"Jason","lastName":"Hunter","email":"bbbb"}, {"firstName":"Elliotte","lastName":"Harold","email":"cccc"} ] }二、org.json.simple.JSON....与net.sf.json.JSON...的区别
1、json的创建
org.json.simple.JSONObject json = new JSONObject(); json.put(key,value);
net.sf.json.JSONObject json = JSONObject.fromObject(str);
net.sf.json.jsonobject 没有 new JSONObject(String)的构造方法
2、解析基本差不多
注：在封装数据是net.sf.json.JSON...明显高效与org.json.simple.JSON....
三、json需要的包
1、org.json.simple.JSONObject和org.json.simple.JSONArray
2、net.sf.json.JSONObject和net.sf.json.JSONArray
缺commons-lang-2.4.jar包：Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/lang/exception/NestableRuntimeException
缺ezmorph-1.0.6.jar包：Exception in thread "main" java.lang.NoClassDefFoundError: net/sf/ezmorph/Morpher
缺commons-logging-1.1.1.jar包：Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/logging/LogFactory
缺commons-collections-3.1.jar包：Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/collections/map/ListOrderedMap
缺commons-beanutils-1.8.0.jar包：Exception in thread "main" java.lang.NoClassDefFoundError: org/apache/commons/beanutils/DynaBean
参考自： JSON_百度百科 JSON中国 | JSON中文网 JSON 教程
四、实例介绍
1、JSONtest类
public class JSONtest {
public static void main(String[] args) {
//将Java对象转换成JSONObject对象并输出
javaObjectToJSONObject();
//将javaObjectList转换为JSONArray并输出
javaObjectListToJSONArray();
//将Java对象转换成JSONObject对象并输出
javaObjectToJsonObject();
//将javaObjectList转换为JSONArray并输出
javaObjectListToJsonArray();
//stringArray转换为net.sf.json.JSONArray并输出
stringArrayToJsonArray();
//将stringArray转换为org.json.simple.JSONArray
stringArrayToJSONArray();
}
public static void stringArrayToJSONArray(){
String[] strArr = {"s1","s2","s3"};
org.json.simple.JSONArray jsonArray = new org.json.simple.JSONArray();
for(int i = 0; i < strArr.length; i++){
jsonArray.add(strArr[i]);
}
System.out.println("jsonArray = "+jsonArray);
int len = jsonArray.size();
for(int i = 0; i < len; i++){
System.out.println(jsonArray.get(i));
}
}
输出为：
jsonArray = ["s1","s2","s3"]
s1
s2
s3
public static void stringArrayToJsonArray(){
String[] strArr = {"s1","s2","s3"};
net.sf.json.JSONArray jsonArray = net.sf.json.JSONArray.fromObject(strArr);
System.out.println("jsonArray = "+jsonArray);
int len = jsonArray.size();
for(int i = 0; i < len; i++){
System.out.println(jsonArray.get(i));
}
}
输出为：
jsonArray = ["s1","s2","s3"]
s1
s2
s3
public static void javaObjectListToJsonArray(){
List personList = createPersonList();
net.sf.json.JSONArray jsonArray = net.sf.json.JSONArray.fromObject(personList);
System.out.println("net.sf.json.JSONArray \n jsonArray = "+jsonArray);
int len = jsonArray.size();
for(int i = 0; i < len; i++){
net.sf.json.JSONObject jsonObject = (net.sf.json.JSONObject)jsonArray.get(i);
System.out.println(jsonObject.get("id")+" | "+jsonObject.get("userName")+" | "
+jsonObject.get("age"));
}
}
输出为net.sf.json.JSONArray ：
jsonArray = [{"age":0,"id":0,"userName":"shaoyesun0"},{"age":1,"id":1,"userName":"shaoyesun1"},{"age":2,"id":2,"userName":"shaoyesun2"},{"age":3,"id":3,"userName":"shaoyesun3"},{"age":4,"id":4,"userName":"shaoyesun4"},{"age":5,"id":5,"userName":"shaoyesun5"},{"age":6,"id":6,"userName":"shaoyesun6"},{"age":7,"id":7,"userName":"shaoyesun7"},{"age":8,"id":8,"userName":"shaoyesun8"},{"age":9,"id":9,"userName":"shaoyesun9"}]
0 | shaoyesun0 | 0
1 | shaoyesun1 | 1
2 | shaoyesun2 | 2
3 | shaoyesun3 | 3
4 | shaoyesun4 | 4
5 | shaoyesun5 | 5
6 | shaoyesun6 | 6
7 | shaoyesun7 | 7
8 | shaoyesun8 | 8
9 | shaoyesun9 | 9
public static void javaObjectToJsonObject(){
Person person = createPerson();
net.sf.json.JSONObject jsonObject = net.sf.json.JSONObject.fromObject(person);
System.out.println("net.sf.json.JSONObject \n jsonObject = "+jsonObject);
System.out.println(jsonObject.get("id")+" | "+jsonObject.get("userName")+" | "
+jsonObject.get("age"));
}
输出为net.sf.json.JSONObject：
jsonObject = {"age":1,"id":1,"userName":"shaoyesun1"}
1 | shaoyesun1 | 1
public static void javaObjectListToJSONArray(){
List personList = createPersonList();
org.json.simple.JSONArray jsonArray = new org.json.simple.JSONArray();
for(Person person : personList){
org.json.simple.JSONObject jsonObject = new org.json.simple.JSONObject();
jsonObject.put("id", person.getId());
jsonObject.put("userName", person.getUserName());
jsonObject.put("age", person.getAge());
jsonArray.add(jsonObject);
}
System.out.println("org.json.simple.JSONArray \n jsonArray = "+jsonArray);
int len = jsonArray.size();
for(int i = 0; i < len; i++){
org.json.simple.JSONObject jsonObject = (org.json.simple.JSONObject)jsonArray.get(i);
System.out.println(jsonObject.get("id")+" | "+jsonObject.get("userName")+" | "
+jsonObject.get("age"));
}
}
输出为org.json.simple.JSONArray：
jsonArray = [{"id":0,"userName":"shaoyesun0","age":0},{"id":1,"userName":"shaoyesun1","age":1},{"id":2,"userName":"shaoyesun2","age":2},{"id":3,"userName":"shaoyesun3","age":3},{"id":4,"userName":"shaoyesun4","age":4},{"id":5,"userName":"shaoyesun5","age":5},{"id":6,"userName":"shaoyesun6","age":6},{"id":7,"userName":"shaoyesun7","age":7},{"id":8,"userName":"shaoyesun8","age":8},{"id":9,"userName":"shaoyesun9","age":9}]
0 | shaoyesun0 | 0
1 | shaoyesun1 | 1
2 | shaoyesun2 | 2
3 | shaoyesun3 | 3
4 | shaoyesun4 | 4
5 | shaoyesun5 | 5
6 | shaoyesun6 | 6
7 | shaoyesun7 | 7
8 | shaoyesun8 | 8
9 | shaoyesun9 | 9
public static void javaObjectToJSONObject(){
Person p = createPerson();
org.json.simple.JSONObject jsonObject = new org.json.simple.JSONObject();
jsonObject.put("id", p.getId());
jsonObject.put("userName", p.getUserName());
jsonObject.put("age", p.getAge());
System.out.println("org.json.simple.JSONObject \n jsonObject = "+jsonObject);
System.out.println(jsonObject.get("id")+" | "+jsonObject.get("userName")+" | "
+jsonObject.get("age"));
}
输出为org.json.simple.JSONObject ：
jsonObject = {"id":1,"userName":"shaoyesun1","age":1}
1 | shaoyesun1 | 1
public static Person createPerson(){
Person person = new Person();
person.setId(1);
person.setUserName("shaoyesun1");
person.setAge(1);
return person;
}
public static List createPersonList(){
List personList = new ArrayList();
for(int i = 0; i < 10; i++){
Person person = new Person();
person.setId(i);
person.setUserName("shaoyesun"+i);
person.setAge(i);
personList.add(person);
}
return personList;
}
}
2、Person类
public class Person {
private long id;
private String userName;
private int age;
}
