json字符串和对象直接的转化

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import java.util.List;
public class JsonUtils {
    // 定义jackson对象
    private static final ObjectMapper MAPPER = new ObjectMapper();
    /**
     * 将对象转换成json字符串。
     */
    public static String objectToJson(Object data) {
      try {
      String string = MAPPER.writeValueAsString(data);
      return string;
    } catch (JsonProcessingException e) {
      e.printStackTrace();
    }
      return null;
    }
    /**
     * 将json结果集转化为对象
     */
    public static <T> T jsonToPojo(String jsonData, Class<T> beanType) {
        try {
            T t = MAPPER.readValue(jsonData, beanType);
            return t;
        } catch (Exception e) {
          e.printStackTrace();
        }
        return null;
    }
    /**
     * 将json数据转换成pojo对象list
     */
    public static <T>List<T> jsonToList(String jsonData, Class<T> beanType) {
      JavaType javaType = MAPPER.getTypeFactory().constructParametricType(List.class, beanType);
      try {
        List<T> list = MAPPER.readValue(jsonData, javaType);
        return list;
    } catch (Exception e) {
      e.printStackTrace();
    }
      return null;
    }
}