gson的工具类JsonUtils

1、maven依赖包

<dependency>
  <groupId>com.google.code.gson</groupId>
  <artifactId>gson</artifactId>
  <version>2.8.9</version>
</dependency>

2、工具类

import com.google.gson.Gson;
import com.google.gson.GsonBuilder;
import java.util.Optional;

public class JsonUtils {
    private static Gson gson = null;
    private JsonUtils() {
    }
    static {
        if (gson == null) {
            gson = new GsonBuilder()
                    .setDateFormat("yyyy-MM-dd HH:mm:ss")
                    .serializeSpecialFloatingPointValues()
                    .create();
        }
    }

    /**
     * 将对象转换成json格式字符串
     *
     * @param object
     * @return
     */
    public static String objToStr(Object object) {
        return Optional.ofNullable(object)
                .map(obj -> gson.toJson(obj))
                .orElse(null);
    }

    /**
     * 将json字符串转换成对象
     *
     * @param str
     * @param clazz
     * @param <T>
     * @return
     */
    public static <T> T StrToObj(String str, Class<T> clazz) {
        return gson.fromJson(str, clazz);
    }
}