コントローラでのjsonデータとオブジェクト,map,listの相互変換について

手順:1.jackson関連jarパッケージのインポート-jackson-annotations.jar - jackson-core.jar - jackson-databind.jar
2.jacksonのコアオブジェクトの作成:ObjectMapper ObjectMapper=new ObjectMapper()
3.mapperを呼び出す関連方法
オブジェクト回転json

User user = new User("Tom","  ")；
String json = mapper.writeValueAsString(user);
System.out.print(json); //  ：{"name":"Tom","city","  "}

Map回転json

HashMap map = new HashMap();
map.put("name","Kris");
map.put("city","  ");
String json = mapper.writeValueAsString(map);
System.out.print(json);  //  ：{"city":"  ","name":"Kris"}  （HashMap    ）

Map回転json

Map map = new HashMap();
map1.put("01",new User("Tom","  "));
map1.put("02",new User("Kris","  "));
String json = mapper.writeValueAsString(map1);
System.out.println(json); 
  ：
{
	"01":{"name":"Tom","city":"  "},
	"02":{"name":"Kris","city":"  "}
}

ArrayListからjsonへ

ArrayList al = new ArrayList();
al.add("Tom");
al.add("  ");
String json = mapper.writeValueAsString(al);
System.out.print(json);  //  ：["TOM","SHENYANG"]

ArrayListからjsonへ

ArrayList al = new ArrayList();
al.add(new User("Tom","  "));
al.add(new User("Kris","  "));
String json = mapper.writeValueAsString(al);
System.out.print(json);  
  ：
[
	{"name":"Tom","city":"  "},
	{"name":"Kris","city":"  "}
]

jsonトランスオブジェクト

String json = "{\"name\":\"Tom\",\"city\":\"  \"}";
User user = mapper.readValue(json, User.class);
System.out.println(user);

json回転map

 HashMap map = mapper.readValue(json, HashMap.class);
 System.out.println(map);

json回転map

  Map map= mapper.readValue(json, HashMap.class);
  System.out.println(map);

json回転リスト

ArrayList list= mapper.readValue(json, ArrayList.class);
System.out.println(list);

json回転リスト

List list= mapper.readValue(json, ArrayList.class);
System.out.println(list);