Jason 和 Java 对象转化示例
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(); }
/**
* Json转化为map
*/
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; }
}
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
