com.alibaba.软件系统定制开发包下相关方法
JSON相关
1.json转对象
Student o = JSONObject.parseObject(jsonString, Student.class);
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2.json转List
json: 花括号{}
String jsonString = “[{"id":1, "name": "zhangsan", "sex": "male", "age": 18, :city": "Beijing"},{"id": 2, "name": "lisi", "sex": "female", "age": 18, "city": "Shanghai"}]” List<Student> studentList = JSONObject.parseArray(jsonString, Student.class);
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json: 方括号[]
将JSON软件系统定制开发字符串看成是list嵌套list的格式,即List< List< Object> >,获取到list之后,循环list,依次获取内层List< Object >,通过get(0)获取id,get(1)获取name……。
String jsonString = “[[1,"zhangsan","male",18,"Beijing"],[2,"lisi","female",18,"Shanghai"]]”List<List<Object>> list = JSON.parseObject([jsonString], new TypeReference<List<List<Object>>>() {});
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3.对象转json
JSON.toJSONString(user);
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4.List转json
JSON.toJSONString(users);
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JSONObject相关:
1.json转方法
String json = ""; JSONObject jsonObject = JSON.parseObject(json);
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2.JSONObject转json方法
//使用方法jsonObject.getString(key);
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3.JSONObject转List
简单类型的:(json字段与接收字段一致的时候)
例:json:
{ "count": 3, "servers": [{ "fault": null, "id": "5c1ac257-", "cpu_options": { "hw:cpu_threads": null } }]}
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JSONObject jsonObject = JSON.parseObject(json); // 获取到我们的jsonobject参数,并toJSONString String s = JSONArray.toJSONString(jsonObject.get("servers")); // 将json字符串转换为集合对象(实体类就省略了啊) List<AnswerCardVo> cardVos = JSONArray.parseArray(s, AnswerCardVo.class);
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4.Map转JSONObject
//直接调用new方法JSONObject jsonObject = new JSONObject(map);
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以上内容是接收字段与json字段一致的时候,那么不一致的时候怎么处理?
com.fasterxml.jackson包
例:json串内容如下,要转成List
注意:可以看到,该json串中属性名是这样的OS-EXT-STS:task_state,那么我们接收的bean就无法写成这个属性名去接收,所以需要在接收Bean中使用注解@JsonProperty进行处理
json串
{ "count": 3, "servers": [{ "fault": null, "id": "5c1ac257-", "OS-EXT-STS:task_state": null, "cpu_options": { "hw:cpu_threads": null } }]}
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可以看到注解@JsonProperty中指定了要接收哪个的值,这样就可以正常转换了
对象:
public class HwInstance { private String fault; private String id; @JsonProperty("OS-EXT-STS:task_state") private String state; @JsonProperty("cpu_options") private Object options; }
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转List
方法一:
@Autowiredprivate ObjectMapper objectMapper;String json = "";JSONObject jsonObject = JSON.parseObject(json);JavaType javaType = objectMapper.getTypeFactory().constructParametricType(ArrayList.class, HwInstance.class);List<HwInstance> instances = objectMapper.readValue(objectMapper.readTree(jsonObject.toJSONString()).get("servers").toString(), javaType);
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方法二:
@Autowiredprivate ObjectMapper objectMapper;String json = "";List<HwInstance> instances = objectMapper.readValue(objectMapper.readTree(json).get("servers").toString(),new TypeReference<List<HwInstance>>(){});
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注意:可能会遇到报错的情况如下:
报错信息:com.fasterxml.jackson.databind.exc.UnrecognizedPropertyException: Unrecognized field “isleader”
意思是json’中的字段与实体类不匹配,解决办法如下:
办法一:给objectMapper设置一个属性
objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
办法二:给实体类加一个注解
@JsonIgnoreProperties(ignoreUnknown = true)