Java 中 ObjectMapper用法(一个简单 Demo 讲清楚)

{
  "name": "张三",
  "age": 18,
  "skills": ["Java", "Spring"]
}

Map<String, Object> user = new HashMap<>();
user.put("name", "张三");
user.put("age", 18);
user.put("skills", Arrays.asList("Java", "Spring"));

import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.*;
public class ObjectMapperDemo {
    public static void main(String[] args) throws Exception {
        // 1. 创建 ObjectMapper
        ObjectMapper objectMapper = new ObjectMapper();
        // 2. 构造 Java 对象
        Map<String, Object> user = new HashMap<>();
        user.put("name", "张三");
        user.put("age", 18);
        user.put("skills", Arrays.asList("Java", "Spring"));
        // 3. Java 对象 → JSON 字符串
        String json = objectMapper.writeValueAsString(user);
        // 4. 输出结果
        System.out.println(json);
    }
}

objectMapper.writeValueAsString(user);

static ObjectMapper OBJECT_MAPPER = new ObjectMapper();

String json = "{\"name\":\"张三\",\"age\":18}";
ObjectMapper objectMapper = new ObjectMapper();
// JSON → Java Map
Map<String, Object> result =
        objectMapper.readValue(json, Map.class);
System.out.println(result.get("name")); // 张三
System.out.println(result.get("age"));  // 18

String json = "{ \"name\": \"" + name + "\", \"age\": " + age + " }";