jackson 轉json. 過濾null值

@Test

public void tttttt() throws JsonGenerationException, JsonMappingException, IOException {

ObjectMapper mapper = new ObjectMapper();

// 過濾對象的null屬性.

mapper.setSerializationInclusion(Inclusion.NON_NULL);

//  過濾map中的null值

mapper.configure(SerializationConfig.Feature.WRITE_NULL_MAP_VALUES, false);

 

T1 t1 = new T1();

t1.setT(null);

t1.setT1("asdfa");

 

Map<String, Object> map = new HashMap<String, Object>();

map.put("asdf", t1);

map.put("fff", null);

 

List<Map<String, Object>> list = new ArrayList<Map<String, Object>>();

 

list.add(null);

list.add(map);

 

String ret_val = mapper.writeValueAsString(list);

System.out.println(ret_val);

}

 

輸出結果:

[null,{"asdf":{"t1":"asdfa"}}]

 

---

注: list好像沒有可以配置除null.

---

list中的null在 org.codehaus.jackson.map.SerializationConfig.Feature 中沒有發現list的設置有null的開關.

但有一個是否輸出空List的屬性.(就是list有,但里面沒有內容)的WRITE_EMPTY_JSON_ARRAYS

--

設置jackson的很多屬性可以在 org.codehaus.jackson.map.SerializationConfig.Feature和org.codehaus.jackson.map.annotate.JsonSerialize$Inclusion

里找.