1.工程
2.代码：
JsonUtil.java
package com.my.json; import java.util.ArrayList;
import java.util.List; import net.sf.json.JSONArray;
import net.sf.json.JSONObject; public class JsonUtil { /**
* 从一个JSON 对象字符格式中得到一个java对象
*
* @param jsonString
* json字符串
*
* @param pojoCalss
* java对象的class
*
* @return
*/ public static Object jsonString2Object(String jsonString, Class pojoCalss) { Object pojo; JSONObject jsonObject = JSONObject.fromObject(jsonString); pojo = JSONObject.toBean(jsonObject, pojoCalss); return pojo; } /**
*
* 将java对象转换成json字符串<br>
* 支持复杂类型：Java bean 中既有属性又有list
*
* @param javaObj
*
* @return
*/ public static String object2JsonString(Object javaObj) { JSONObject json; json = JSONObject.fromObject(javaObj); return json.toString(); } /**
*
* 从json对象集合表达式中得到一个java对象列表
*
* @param jsonString
*
* @param pojoClass
*
* @return
*/ public static List jsonList2JavaList(String jsonString, Class pojoClass) { JSONArray jsonArray = JSONArray.fromObject(jsonString); JSONObject jsonObject; Object pojoValue; List list = new ArrayList(); for (int i = 0; i < jsonArray.size(); i++) { jsonObject = jsonArray.getJSONObject(i); pojoValue = JSONObject.toBean(jsonObject, pojoClass); list.add(pojoValue); } return list; } /**
*
* 从json对象集合表达式中得到一个java对象列表
*
* @param jsonString
*
* @param pojoClass
*
* @return
*/ public static String javaList2JsonList(List list) { JSONArray jsonArray = JSONArray.fromObject(list);
return jsonArray.toString();
}
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public static Map<String, Object> parseJSON2Map(String jsonStr){
Map<String, Object> map = new HashMap<String, Object>();
//最外层解析
JSONObject json = JSONObject.fromObject(jsonStr);
for(Object k : json.keySet()){
Object v = json.get(k);
//如果内层还是数组的话，继续解析
if(v instanceof JSONArray){
List<Map<String, Object>> list = new ArrayList<Map<String,Object>>();
Iterator<JSONObject> it = ((JSONArray)v).iterator();
while(it.hasNext()){
JSONObject json2 = it.next();
list.add(parseJSON2Map(json2.toString()));
}
map.put(k.toString(), list);
} else {
map.put(k.toString(), v);
}
}
return map;
}
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}
Person.java
package com.my.json; import java.util.ArrayList;
import java.util.List; public class Person { private String name; private List<Person> list = new ArrayList<Person>(); public List<Person> getList() {
return list;
} public void setList(List<Person> list) {
this.list = list;
} @Override
public String toString() {
return "Person [name=" + name + ", num=" + num + ", sex=" + sex
+ ", age=" + age + "]";
} private int num;
private String sex;
private int age; public Person() {
// TODO Auto-generated constructor stub
} public Person(String name, int num, String sex, int age) {
super();
this.name = name;
this.num = num;
this.sex = sex;
this.age = age;
} public String getName() {
return name;
} public void setName(String name) {
this.name = name;
} public int getNum() {
return num;
} public void setNum(int num) {
this.num = num;
} public String getSex() {
return sex;
} public void setSex(String sex) {
this.sex = sex;
} public int getAge() {
return age;
} public void setAge(int age) {
this.age = age;
} }
Test.java
package com.my.json; import java.util.ArrayList;
import java.util.List;
import java.util.Map; import net.sf.json.JSONObject; public class Test {
public static void main(String[] args) { // 将一个java对象转换为Json字符串
Person p = new Person("gu1", 123, "male", 23);
String str = JsonUtil.object2JsonString(p);
System.out.println(str); // 将一个JSON字符串转化为Java对象
String s = "{\"age\":23,\"name\":\"gu1\",\"num\":123,\"sex\":\"male\"}";
Person p2 = (Person) JsonUtil.jsonString2Object(s, Person.class);
System.out.println(p2); // 将一个对象列表转化为JSON列表
List<Person> list = new ArrayList<Person>();
for (int i = 0; i < 5; i++) {
Person persion = new Person("zhang" + i, 1 + i, "man" + i, 1 + i);
list.add(persion);
}
String jsonList = JsonUtil.javaList2JsonList(list);
System.out.println(jsonList); // 将一个JSON列表转化为Java列表
String jst = "[{\"age\":1,\"list\":[],\"name\":\"zhang0\",\"num\":1,\"sex\":\"man0\"},{\"age\":2,\"list\":[],\"name\":\"zhang1\",\"num\":2,\"sex\":\"man1\"},{\"age\":3,\"list\":[],\"name\":\"zhang2\",\"num\":3,\"sex\":\"man2\"},{\"age\":4,\"list\":[],\"name\":\"zhang3\",\"num\":4,\"sex\":\"man3\"},{\"age\":5,\"list\":[],\"name\":\"zhang4\",\"num\":5,\"sex\":\"man4\"}]";
List<Person> l = (List<Person>) JsonUtil.jsonList2JavaList(jst,
Person.class);
System.out.println(l.size()); // 复杂类型转JSON：Java bean 中既有属性又有list（项目中经常见到）
List<Person> list2 = new ArrayList<Person>();
for (int i = 0; i < 10; i++) {
Person persion = new Person("zhang" + i, 1 + i, "man" + i, 1 + i);
list2.add(persion);
}
Person me = new Person("zhang", 1, "man", 1);
me.setList(list2); String str2 = JsonUtil.object2JsonString(me);
System.out.println(str2); // 复杂类型转Java：JSON 中既有属性又有list（项目中经常见到）
String ss = "{\"age\":1,\"list\":[{\"age\":1,\"list\":[],\"name\":\"zhang0\",\"num\":1,\"sex\":\"man0\"},{\"age\":2,\"list\":[],\"name\":\"zhang1\",\"num\":2,\"sex\":\"man1\"},{\"age\":3,\"list\":[],\"name\":\"zhang2\",\"num\":3,\"sex\":\"man2\"},{\"age\":4,\"list\":[],\"name\":\"zhang3\",\"num\":4,\"sex\":\"man3\"},{\"age\":5,\"list\":[],\"name\":\"zhang4\",\"num\":5,\"sex\":\"man4\"},{\"age\":6,\"list\":[],\"name\":\"zhang5\",\"num\":6,\"sex\":\"man5\"},{\"age\":7,\"list\":[],\"name\":\"zhang6\",\"num\":7,\"sex\":\"man6\"},{\"age\":8,\"list\":[],\"name\":\"zhang7\",\"num\":8,\"sex\":\"man7\"},{\"age\":9,\"list\":[],\"name\":\"zhang8\",\"num\":9,\"sex\":\"man8\"},{\"age\":10,\"list\":[],\"name\":\"zhang9\",\"num\":10,\"sex\":\"man9\"}],\"name\":\"zhang\",\"num\":1,\"sex\":\"man\"}";
Map map = (Map)JSONObject.fromObject(ss); System.out.println("------------------------------");
System.out.println(map);
String name = (String)map.get("name");
int num = (Integer)map.get("num");
String sex = (String)map.get("sex");
int age = (Integer)map.get("age");
System.out.println("name="+name);
System.out.println("num="+"num");
System.out.println("sex="+"sex");
System.out.println("age="+"age");
System.out.println("list="+map.get("list"));
//获取list字符串，再转化为Java 对象,其实是再次构建成Java bean
String listStr = map.get("list").toString();//一定要用toString，不能强转
List<Person> ll = JsonUtil.jsonList2JavaList(listStr, Person.class);
//构建新的bean：不知是否有其他方案,根据需要是否构建
Person pp = new Person(name,num,sex,age);
pp.setList(ll);
//输出bean
for (Person ps : pp.getList())
{
System.out.println(ps.getName());
} }
}
输出：
{"age":23,"list":[],"name":"gu1","num":123,"sex":"male"}
Person [name=gu1, num=123, sex=male, age=23]
[{"age":1,"list":[],"name":"zhang0","num":1,"sex":"man0"},{"age":2,"list":[],"name":"zhang1","num":2,"sex":"man1"},{"age":3,"list":[],"name":"zhang2","num":3,"sex":"man2"},{"age":4,"list":[],"name":"zhang3","num":4,"sex":"man3"},{"age":5,"list":[],"name":"zhang4","num":5,"sex":"man4"}]
5
{"age":1,"list":[{"age":1,"list":[],"name":"zhang0","num":1,"sex":"man0"},{"age":2,"list":[],"name":"zhang1","num":2,"sex":"man1"},{"age":3,"list":[],"name":"zhang2","num":3,"sex":"man2"},{"age":4,"list":[],"name":"zhang3","num":4,"sex":"man3"},{"age":5,"list":[],"name":"zhang4","num":5,"sex":"man4"},{"age":6,"list":[],"name":"zhang5","num":6,"sex":"man5"},{"age":7,"list":[],"name":"zhang6","num":7,"sex":"man6"},{"age":8,"list":[],"name":"zhang7","num":8,"sex":"man7"},{"age":9,"list":[],"name":"zhang8","num":9,"sex":"man8"},{"age":10,"list":[],"name":"zhang9","num":10,"sex":"man9"}],"name":"zhang","num":1,"sex":"man"}
------------------------------
{"age":1,"list":[{"age":1,"list":[],"name":"zhang0","num":1,"sex":"man0"},{"age":2,"list":[],"name":"zhang1","num":2,"sex":"man1"},{"age":3,"list":[],"name":"zhang2","num":3,"sex":"man2"},{"age":4,"list":[],"name":"zhang3","num":4,"sex":"man3"},{"age":5,"list":[],"name":"zhang4","num":5,"sex":"man4"},{"age":6,"list":[],"name":"zhang5","num":6,"sex":"man5"},{"age":7,"list":[],"name":"zhang6","num":7,"sex":"man6"},{"age":8,"list":[],"name":"zhang7","num":8,"sex":"man7"},{"age":9,"list":[],"name":"zhang8","num":9,"sex":"man8"},{"age":10,"list":[],"name":"zhang9","num":10,"sex":"man9"}],"name":"zhang","num":1,"sex":"man"}
name=zhang
num=num
sex=sex
age=age
list=[{"age":1,"list":[],"name":"zhang0","num":1,"sex":"man0"},{"age":2,"list":[],"name":"zhang1","num":2,"sex":"man1"},{"age":3,"list":[],"name":"zhang2","num":3,"sex":"man2"},{"age":4,"list":[],"name":"zhang3","num":4,"sex":"man3"},{"age":5,"list":[],"name":"zhang4","num":5,"sex":"man4"},{"age":6,"list":[],"name":"zhang5","num":6,"sex":"man5"},{"age":7,"list":[],"name":"zhang6","num":7,"sex":"man6"},{"age":8,"list":[],"name":"zhang7","num":8,"sex":"man7"},{"age":9,"list":[],"name":"zhang8","num":9,"sex":"man8"},{"age":10,"list":[],"name":"zhang9","num":10,"sex":"man9"}]
zhang0
zhang1
zhang2
zhang3
zhang4
zhang5
zhang6
zhang7
zhang8
zhang9