关于java:对象与json转换

/** * 测试简略对象的转化 */@Testpublic void test01() throws JsonProcessingException {    ObjectMapper objectMapper = new ObjectMapper();    ItemDesc itemDesc = new ItemDesc();    itemDesc.setItemId(100L).setItemDesc("商品详情信息")            .setCreated(new Date()).setUpdated(new Date());    //对象转化为json    String json = objectMapper.writeValueAsString(itemDesc);    System.out.println(json);    //json转化为对象    ItemDesc itemDesc2 = objectMapper.readValue(json, ItemDesc.class);    System.out.println(itemDesc2.getItemDesc());}/** * 测试汇合对象的转化 */@Testpublic void test02() throws JsonProcessingException {    ObjectMapper objectMapper = new ObjectMapper();    ItemDesc itemDesc = new ItemDesc();    itemDesc.setItemId(100L).setItemDesc("商品详情信息1")            .setCreated(new Date()).setUpdated(new Date());    ItemDesc itemDesc2 = new ItemDesc();    itemDesc2.setItemId(100L).setItemDesc("商品详情信息2")            .setCreated(new Date()).setUpdated(new Date());    List<ItemDesc> lists = new ArrayList<>();    lists.add(itemDesc);    lists.add(itemDesc2);    //[{key:value},{}]    String json = objectMapper.writeValueAsString(lists);    System.out.println(json);    //将json串转化为对象    List<ItemDesc> list2 = objectMapper.readValue(json, lists.getClass());    System.out.println(list2);}