1.所依赖JAR包

要使程序可以运行必须引入JSON-lib包，JSON-lib包同时依赖于以下的JAR包：

1. commons-lang.jar
2. commons-beanutils.jar
3. commons-collections.jar
4. commons-logging.jar 
5. ezmorph.jar
6. json-lib-2.2.2-jdk15.jar

2.Demo

 2.1 应用场景:

•    后台的java类，如实体类、List、Set、Map转成json字符串发送到其它项目或者jsp端
•   jsp端或者其它项目发送过来的json字符串，需要解析成l实体类、List、Set、Map等java类

 2.2 Student实体类

package json;import java.util.Date;import java.util.List;import java.util.Map;import java.util.Set;public class Student {     private int id;     private String name;     private String age;     private Date birthDay;     private List list;     private Set set;     private Map map;    public int getId() {        return id;    }    public void setId(int id) {        this.id = id;    }    public String getName() {        return name;    }    public void setName(String name) {        this.name = name;    }    public String getAge() {        return age;    }    public void setAge(String age) {        this.age = age;    }        public Date getBirthDay() {        return birthDay;    }    public void setBirthDay(Date birthDay) {        this.birthDay = birthDay;    }        public List getList() {        return list;    }    public void setList(List list) {        this.list = list;    }    public Set getSet() {        return set;    }    public void setSet(Set set) {        this.set = set;    }        public Map getMap() {        return map;    }    public void setMap(Map map) {        this.map = map;    }    @Override    public String toString() {        return "Student [id=" + id + ", name=" + name + ", age=" + age                + ", birthDay=" + birthDay + ", list=" + list + ", set=" + set                + ", map=" + map + "]";    }         }

2.3 java对象序列化成json对象时，处理日期的处理类

package json;import java.text.SimpleDateFormat;import java.util.Date;import net.sf.json.JsonConfig;import net.sf.json.processors.JsonValueProcessor;/** *  * @author yangguojun * java实体类转jsonObject时,日期处理类 */public class JsonDateValueProcessor implements JsonValueProcessor {     /**      * 集合中实体类日期处理      */    @Override    public Object processArrayValue(Object value , JsonConfig config) {        // TODO Auto-generated method stub        return processor(value);    }    /**     * 当个实体类日期处理     */    @Override    public Object processObjectValue(String propertyName, Object value, JsonConfig config) {        return processor(value);    }    /**     * 把日期对象转为字符串     * @param value     * @return     */    private Object processor(Object value){        SimpleDateFormat format = new SimpleDateFormat("yyyy-MM-dd HH:mm:ss");        if(value instanceof Date){            return format.format(value);        }        return value == null ? "":value.toString();            }}

2.4 测试类

package json;import java.util.ArrayList;import java.util.Date;import java.util.HashMap;import java.util.HashSet;import net.sf.json.JSON;import net.sf.json.JSONArray;import net.sf.json.JSONObject;import net.sf.json.JsonConfig;public class JsonDemo {    public static void main(String[] args) {        //创建JSON对象的第一种方法        JSONObject jsonObj1 = new JSONObject();        jsonObj1.put("id", "1");        jsonObj1.put("name", "rose");        jsonObj1.put("age", 25);        System.out.println("jsonObj1"+jsonObj1);        //创建JSON对象的第二种方法        HashMap
     
       map = new HashMap
      
       ();        map.put("id", "2");        map.put("name", "zhangsan");        map.put("age", "25");        JSONObject jsonObj2 = JSONObject.fromObject(map);        System.out.println("jsonObj2"+jsonObj2);                 //创建一个JsonArray方法1        JSONArray jsonArray = new JSONArray();        jsonArray.add(0, "ZHULI");        jsonArray.add(1, "30");        jsonArray.add(2, "ALI");        System.out.println("jsonArray1：" + jsonArray);                //创建JsonArray方法2        ArrayList
       
         arrayList = new ArrayList
        
         ();        arrayList.add("柯文修");        arrayList.add("23");        arrayList.add("5");        System.out.println("jsonArray2：" + JSONArray.fromObject(arrayList));                //创建一个复杂JSON对象（JSON对象里有JSON数组）        JSONObject jsonObj3 = new JSONObject();        jsonObj3.put("id", 3);        jsonObj3.put("name", "lisi");        jsonObj3.put("age", 23);        jsonObj3.put("arrayList", arrayList);        System.out.println("jsonObj3"+jsonObj3);                //创建一个复杂JSON数组(JSON数组里含有JSON对象)、        JSONArray jsonArray3 = new JSONArray();        jsonArray3.add("4");        jsonArray3.add("wangwu");        jsonArray3.add("26");        jsonArray3.add(map);        System.out.println("jsonArray3"+jsonArray3);               //把JSON字符串转为JSON对象        String jsonString = "{\"id\":3,\"name\":\"lisi\",\"age\":23,\"arrayList\":[\"ZHULI\",\"30\",\"ALI\"]}";        JSONObject jsonObj4 = JSONObject.fromObject(jsonString);        System.out.println(jsonObj4.get("id")+"--"+jsonObj4.get("name")+"--"+jsonObj4.get("age")+                "--"+jsonObj4.get("arrayList"));        //java实体类转为JSONObject        Student stu = new Student();        stu.setId(1);        stu.setName("罗志茂");        stu.setAge("23");        stu.setBirthDay(new Date());        stu.setList(arrayList);        HashSet
         
        
       
      
     

 2.5 测试结果

  jsonObj1{"id":"1","name":"rose","age":25}

  jsonObj2{"id":"2","age":"25","name":"zhangsan"}

  jsonArray1：["ZHULI","30","ALI"]

  jsonArray2：["柯文修","23","5"]

  jsonObj3{"id":3,"name":"lisi","age":23,"arrayList":["柯文修","23","5"]}

  jsonArray3["4","wangwu","26",{"id":"2","age":"25","name":"zhangsan"}]

  3--lisi--23--["ZHULI","30","ALI"]

 序列化:{"age":"23","birthDay":"2016-08-13 23:22:27","id":1,"list":["柯文修","23","5"],"map":{"id":"2","age":"25","name":"zhangsan"},"name":"罗志茂","set":  ["戚广辉","6","25"]}

 反序列化:Student [id=1, name=罗志茂, age=23, birthDay=Sat Aug 13 23:22:27 CST 2016, list=[柯文修, 23, 5], set=[戚广辉, 6, 25], map={id=2,  name=zhangsan, age=25}]