jackson 進行json與java對象轉換 之三

二、測試類，沒用Junit，用Main()方法輸出。

 

    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: 主要用於測試學習用jackson包實現json、對象、Map之間的轉換 * * 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("張三"); 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("河南省濟源市"); 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("大紅袍"); user.setList(list); Set set=new HashSet(); set.add("籃球"); set.add("足球"); set.add("乒乓球"); user.setSet(set); ObjectMapper mapper = new ObjectMapper(); //轉換器 //測試01：對象--json String json=mapper.writeValueAsString(user); //將對象轉換成json  System.out.println(json); /* 結果以下： {"id":"01","name":"張三","age":33,"pay":6666.88,"valid":true,"one":"E","birthday":1465185448998, "link":{"phone":"13899995555","address":"河南省濟源市","qq":"123456"}, "map":{"aa":"this is aa","bb":"this is bb","cc":"this is cc"}, "list":["普洱","大紅袍"], "set":["乒乓球","足球","籃球"]} 注意點：（1） 日期--長整型 （2）List、Set均轉成數組 */ //測試02：json--map Map m = mapper.readValue(json, Map.class); //json轉換成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 /* 結果以下： 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 注意點：（1） 日期--長整型 （2）map、子對象均轉換成了LinkedHashMap （3）List、Set均轉成ArrayList */ //測試03：map--json json=mapper.writeValueAsString(m); //map轉json System.out.println(json); //與以前格式徹底相同，說明通過map轉換後，信息沒有丟失 //測試04：json--對象 User u=mapper.readValue(json, User.class); //json轉java對象。經測，轉成對象後，一切恢復正常 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()); //測試05：其餘轉換 byte[] data=mapper.writeValueAsBytes(u); //對象轉成二進制數組  } } 

三、輸出結果

    {"id":"01","name":"張三","age":33,"pay":6666.88,"valid":true,"one":"E","birthday":632448000000,"link":{"phone":"13899995555","address":"河南省濟源市","qq":"123456"},"map":{"aa":"this is aa","bb":"this is bb","cc":"this is cc"},"list":["普洱","大紅袍"],"set":["乒乓球","足球","籃球"]} 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":"張三","age":33,"pay":6666.88,"valid":true,"one":"E","birthday":632448000000,"link":{"phone":"13899995555","address":"河南省濟源市","qq":"123456"},"map":{"aa":"this is aa","bb":"this is bb","cc":"this is cc"},"list":["普洱","大紅袍"],"set":["乒乓球","足球","籃球"]} 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, 大紅袍] set：[足球, 乒乓球, 籃球]