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
     * 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
      
        parseJSON2Map(String jsonStr){          Map
       
         map = new HashMap
        
         ();          //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
         
        
       
      

　　

}

Person.java

package com.my.json;import java.util.ArrayList;import java.util.List;public class Person {    private String name;    private List
     
       list = new ArrayList
      
       ();    public List
       
         getList() {        return list;    }    public void setList(List
        
          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
     
       list = new ArrayList
      
       ();        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
       
         l = (List
        
         ) 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
         
           list2 = new ArrayList
          
           (); 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
           
             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