jackson 转json. 过滤null值

@Test

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

ObjectMapper mapper = new ObjectMapper();

// 过滤对象的null属性.

mapper.setSerializationInclusion(Inclusion.NON_NULL);

// 过滤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);

}

 

输出结果:

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

 

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注: list好像没有可以配置除null.

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list中的null在 org.codehaus.jackson.map.SerializationConfig.Feature 中没有发现list的设置有null的开关.

但有一个是否输出空List的属性.(就是list有,但里面没有内容)的WRITE_EMPTY_JSON_ARRAYS

--

设置jackson的很多属性可以在 org.codehaus.jackson.map.SerializationConfig.Feature和org.codehaus.jackson.map.annotate.JsonSerialize$Inclusion

里找.