平時我們一般使用阿裡的Fastjson庫,但是也會使用Jackson對于簡單泛型是可以正常操作的,但是如果對于太過于複雜的泛型類有時會不成功。目前還在找着更合适的Json庫。不過這一點在dotnet原生方案JavaScriptSerializer可以完美解決這一些問題,無論泛型多複雜。
這裡我們就列舉一些常用的序列化和反序列的示例:
ObjectMapper mapper = new ObjectMapper();
User user = new User();
user.setId(1);
Pager<User> pager = new Pager<User>();
List<User> users = new ArrayList<User>();
users.add(user);
pager.setDatas(users);
String json = mapper.writeValueAsString(pager);
// 方式1
Pager<User> userPager1 = mapper.readValue(json, new TypeReference<Pager<User>>() {});
// 方式2
Type[] types = new Type[1];
types[0] = User.class;
final ParameterizedTypeImpl type = ParameterizedTypeImpl.make(Pager.class, types, Pager.class.getDeclaringClass());
TypeReference typeReference = new TypeReference<Pager>() {
@Override
public Type getType() {
return type;
}
};
Pager<User> userPager2 = mapper.readValue(json, typeReference);
// 方式3
JavaType javaType = mapper.getTypeFactory().constructParametrizedType(Pager.class, Pager.class, User.class);
Pager<User> userPager3 = mapper.readValue(json, javaType);
// 方式4
JavaType javaType1 = mapper.getTypeFactory().constructParametricType(Pager.class, User.class);
Pager<User> userPager4 = mapper.readValue(json, javaType1);
// 方式5,建立另一個指定具體泛型T的參數的類
PagerAppoint userPager5 = mapper.readValue(json, PagerAppoint.class);
// 數組泛型的序列化和反序列化
String json1 = mapper.writeValueAsString(users);
JavaType javaType2 = mapper.getTypeFactory().constructParametricType(List.class, User.class);
List<User> users1 = mapper.readValue(json1, javaType2);
// HashMap
Map<String, User> map = new HashMap<String, User>(16);
map.put("test", user);
String json2 = mapper.writeValueAsString(map);
// 1
Map<String, User> users2 = mapper.readValue(json2, new TypeReference<Map<String, User>>() {});
// 2
JavaType javaType3 = mapper.getTypeFactory().constructParametricType(HashMap.class, String.class, User.class);
Map<String, User> users3 = mapper.readValue(json2, javaType3);