首先加入依赖：     
       <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
           
        </dependency>

详细工具类：

@Slf4j
public class JsonUtil {
    private static ObjectMapper objectMapper = new ObjectMapper();

    public static String toJson(Object object) {
        try{
          return objectMapper.writeValueAsString(object)  ;
        }catch(JsonProcessingException e) {
            e.printStackTrace();
        }
        return null;
    }

    public static Object fromJson(String string,Class classType){
        try{
            return objectMapper.readValue(string,classType)  ;
        }catch(IOException e) {
            e.printStackTrace();
        }
        return null;
    }
}