jackson 进行json与java对象转换 之三

2、测试类，没用Junit，用Main()方法输出。

    package test;  

    import java.io.IOException;
    import java.util.ArrayList;
    import java.util.Date;
    import java.util.HashMap;
    import java.util.HashSet;
    import java.util.List;
    import java.util.Map;
    import java.util.Set;
    import org.codehaus.jackson.JsonGenerationException;
    import org.codehaus.jackson.map.JsonMappingException;
    import org.codehaus.jackson.map.ObjectMapper;  

    /**
     * Description: 主要用于测试学习用jackson包实现json、对象、Map之间的转换
     *
     * Date: 2016年6月6日
     * Time: 下午3:23:23
     */
    public class JsonTest
    {  

        public static void main(String[] args) throws JsonGenerationException, JsonMappingException, IOException
        {
            User user=new User();
            user.setId("01");
            user.setName("张三");
            user.setAge(33);
            user.setPay(6666.88);
            user.setValid(true);
            user.setOne('E');
            user.setBirthday(new Date(20l*366*24*3600*1000)); //1990年  

            Link link = new Link();
            link.setAddress("河南省济源市");
            link.setPhone("13899995555");
            link.setQq("123456");
            user.setLink(link);  

            Map map=new HashMap();
            map.put("aa", "this is aa");
            map.put("bb", "this is bb");
            map.put("cc", "this is cc");
            user.setMap(map);  

            List list=new ArrayList(){};
            list.add("普洱");
            list.add("大红袍");
            user.setList(list);  

            Set set=new HashSet();
            set.add("篮球");
            set.add("足球");
            set.add("乒乓球");
            user.setSet(set);  

            ObjectMapper mapper = new ObjectMapper(); //转换器  

            //测试01：对象--json
            String json=mapper.writeValueAsString(user); //将对象转换成json
            System.out.println(json);
            /* 结果如下：
            {"id":"01","name":"张三","age":33,"pay":6666.88,"valid":true,"one":"E","birthday":1465185448998,
            "link":{"phone":"13899995555","address":"河南省济源市","qq":"123456"},
            "map":{"aa":"this is aa","bb":"this is bb","cc":"this is cc"},
            "list":["普洱","大红袍"],
            "set":["乒乓球","足球","篮球"]} 

            注意点：（1） 日期--长整型 （2）List、Set均转成数组
             */  

            //测试02：json--map
            Map m = mapper.readValue(json, Map.class); //json转换成map  

            System.out.println("pay："+m.get("pay").getClass().getName()); //java.lang.Double
            System.out.println("valid："+m.get("valid").getClass().getName()); //java.lang.Boolean
            System.out.println("birthday："+m.get("birthday").getClass().getName()); //java.lang.Long
            System.out.println("link："+m.get("link").getClass().getName()); //java.util.LinkedHashMap
            System.out.println("map："+m.get("map").getClass().getName()); //java.util.LinkedHashMap
            System.out.println("list："+m.get("list").getClass().getName()); //java.util.ArrayList
            System.out.println("set："+m.get("set").getClass().getName()); //java.util.ArrayList
            /*  结果如下：
                pay：java.lang.Double
                valid：java.lang.Boolean
                birthday：java.lang.Long
                link：java.util.LinkedHashMap
                map：java.util.LinkedHashMap
                list：java.util.ArrayList
                set：java.util.ArrayList 

                注意点：（1） 日期--长整型  （2）map、子对象均转换成了LinkedHashMap （3）List、Set均转成ArrayList
             */  

            //测试03：map--json
            json=mapper.writeValueAsString(m); //map转json
            System.out.println(json); //与之前格式完全相同，说明经过map转换后，信息没有丢失  

            //测试04：json--对象
            User u=mapper.readValue(json, User.class); //json转java对象。经测，转成对象后，一切恢复正常
            System.out.println("pay："+u.getPay());
            System.out.println("valid："+u.isValid());
            System.out.println("birthday："+u.getBirthday());
            System.out.println("link："+u.getLink());
            System.out.println("map："+u.getMap());
            System.out.println("list："+u.getList());
            System.out.println("set："+u.getSet());  

            //测试05：其他转换
            byte[] data=mapper.writeValueAsBytes(u); //对象转成二进制数组  

        }  

    }  

3、输出结果

    {"id":"01","name":"张三","age":33,"pay":6666.88,"valid":true,"one":"E","birthday":632448000000,"link":{"phone":"13899995555","address":"河南省济源市","qq":"123456"},"map":{"aa":"this is aa","bb":"this is bb","cc":"this is cc"},"list":["普洱","大红袍"],"set":["乒乓球","足球","篮球"]}
    pay：java.lang.Double
    valid：java.lang.Boolean
    birthday：java.lang.Long
    link：java.util.LinkedHashMap
    map：java.util.LinkedHashMap
    list：java.util.ArrayList
    set：java.util.ArrayList
    {"id":"01","name":"张三","age":33,"pay":6666.88,"valid":true,"one":"E","birthday":632448000000,"link":{"phone":"13899995555","address":"河南省济源市","qq":"123456"},"map":{"aa":"this is aa","bb":"this is bb","cc":"this is cc"},"list":["普洱","大红袍"],"set":["乒乓球","足球","篮球"]}
    pay：6666.88
    valid：true
    birthday：Tue Jan 16 08:00:00 CST 1990
    link：test.Link@350385f1
    map：{aa=this is aa, bb=this is bb, cc=this is cc}
    list：[普洱, 大红袍]
    set：[足球, 乒乓球, 篮球]