springboot工程中使用ObjectMapper解析JSON字符串

package com.txc.objectmapper.controller; import com.fasterxml.jackson.annotation.JsonInclude; import com.fasterxml.jackson.core.JsonParser; import com.fasterxml.jackson.databind.DeserializationFeature; import com.fasterxml.jackson.databind.JsonNode; import com.fasterxml.jackson.databind.ObjectMapper; import com.fasterxml.jackson.databind.SerializationFeature; import com.txc.objectmapper.bean.Student; import org.springframework.stereotype.Controller; import org.springframework.web.bind.annotation.RequestMapping; import org.springframework.web.bind.annotation.ResponseBody; import java.util.*; @Controller public class TestObjectMapperController { /** * 实现对象和JSON之间互转 */ @RequestMapping("/jsonObjectChange") @ResponseBody public void jsonObjectChange() throws Exception{ ObjectMapper mapper = new ObjectMapper(); String param = "{\"stu_id\":\"1001\",\"stu_name\":\"晓春\"}"; //将字符串转换为对象 Student student = mapper.readValue(param, Student.class); System.out.println("===json转对象==="+student.toString()); //将对象转化成JSON String json = mapper.writeValueAsString(student); System.out.println("===对象转json==="+json); } /** * 集合和JSON相互转化 */ @RequestMapping("/listAndJSONChange") @ResponseBody public void arrayToObject() throws Exception{ Student student1=new Student("1001","晓春1"); Student student2=new Student("1002","晓春2"); ObjectMapper mapper = new ObjectMapper(); //集合转json String param = mapper.writeValueAsString(Arrays.asList(student1,student2)); System.out.println("==集合转json=="+param); //数组json转化成集合 List<Student> list= mapper.readValue(param, List.class); System.out.println("==数组json转集合=="+list); } /** * map和json相互转化 */ @RequestMapping("/mapAndJsonChange") @ResponseBody public void mapAndJsonChange() throws Exception{ ObjectMapper mapper = new ObjectMapper(); Map<String, Object> map = new HashMap<>(); map.put("id", "1001"); map.put("name","晓春"); map.put("student", new Student("6","6")); String param = mapper.writeValueAsString(map); System.out.println("===map转json==="+param); Map<String, Object> resultMap = mapper.readValue(param, Map.class); System.out.println("===json转map==="+resultMap); } @RequestMapping("/readTree") @ResponseBody public void readTree() throws Exception{ String params="{\"students\":[{\"stu_id\":\"1001\",\"stu_name\":\"十一郎\"},{\"stu_id\":\"1002\",\"stu_name\":\"十二郎\"}],\"flag\":\"1\",\"teacher\":{\"tea_id\":\"2001\",\"tea_name\":\"晓春\"}}"; ObjectMapper mapper = new ObjectMapper(); //将JSON转化成Tree JsonNode node= mapper.readTree(params); //得到results这个节点下的信息 JsonNode contents=node.get("students"); System.out.println(contents.get(0)); System.out.println(contents.get(0).get("stu_id")); } //常见问题2：属性为null，不序列化 @RequestMapping("/commonQuestion2") @ResponseBody public void commonQuestion1() throws Exception{ ObjectMapper mapper = new ObjectMapper(); Student student=new Student("1001",null); //属性为null不参与序列化 mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL); //将字符串转换为对象 String param= mapper.writeValueAsString(student); System.out.println("===null值不参与序列化==="+param); } //objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false); //常见问题4：Json字符串里数字类型值为正无穷、负无穷或NaN时 @RequestMapping("/commonQuestion10") @ResponseBody public void commonQuestion10() throws Exception{ ObjectMapper mapper = new ObjectMapper(); mapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false); String date=mapper.writeValueAsString(new Date()); //==date=="2023-11-07T12:28:36.374+00:00" System.out.println("==date=="+date); } }