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 = http://www.mamicode.com/JSONObject.toBean(jsonObject, pojoClass);>
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/**<br>* Json转化为map<br>*/<br>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;  
    } 
　　
}

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;    }}

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());        }                }}