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]