kcim-cost/src/main/java/com/imed/costaccount/common/util/JacksonUtil.java

package com.imed.costaccount.common.util;

import cn.hutool.core.util.StrUtil;
import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.SerializationFeature;
import lombok.extern.slf4j.Slf4j;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.HashMap;
import java.util.Map;
import java.util.Objects;

/**
 * spring自带的jackson（json）工具类
 */
@Slf4j
public class JacksonUtil {
    private static ObjectMapper objectMapper = new ObjectMapper();
    // 日起格式化
    private static final String STANDARD_FORMAT = "yyyy-MM-dd HH:mm:ss";

    // 以下静态初始化可以根据需求去掉对应的
    static {
        //对象的所有字段全部列入
        objectMapper.setSerializationInclusion(JsonInclude.Include.ALWAYS);
        //取消默认转换timestamps形式
        objectMapper.configure(SerializationFeature.WRITE_DATES_AS_TIMESTAMPS, false);
        //忽略空Bean转json的错误
        objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);
        //所有的日期格式都统一为以下的样式，即yyyy-MM-dd HH:mm:ss
        objectMapper.setDateFormat(new SimpleDateFormat(STANDARD_FORMAT));
        //忽略 在json字符串中存在，但是在java对象中不存在对应属性的情况。防止错误
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);
    }

    /**
     * 对象转json 字符串
     *
     * @param obj 对象
     * @return Json格式字符串
     */
    public static <T> String obj2Str(T obj) {
        try {
            return obj instanceof String ? (String) obj : objectMapper.writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            log.error("parse object to string error {}", e.getMessage());
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 对象转Json格式字符串(格式化的Json字符串)
     *
     * @param obj 对象
     * @return 美化的Json格式字符串
     */
    public static <T> String obj2StrPretty(T obj) {
        if (obj == null) {
            return null;
        }
        try {
            return obj instanceof String ? (String) obj : objectMapper.writerWithDefaultPrettyPrinter().writeValueAsString(obj);
        } catch (JsonProcessingException e) {
            log.warn("Parse Object to String error : {}", e.getMessage());
            return null;
        }
    }

    /**
     * json字符串转对象
     *
     * @param str   json字符串
     * @param clazz clazz对象
     * @param <T>   泛型
     * @return T
     */
    public static <T> T str2Obj(String str, Class<T> clazz) {
        if (StrUtil.isBlank(str) || Objects.isNull(clazz)) {
            log.error("parse string to object error : Params is null");
            return null;
        }
        T t = null;

        try {
            t = clazz.equals(String.class) ? (T) str : objectMapper.readValue(str, clazz);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
        }
        return t;
    }

    /**
     * 字符串转List等集合类型使用
     *   样例：
     *      *  JacksonUtil.string2ObjList(str,new TypeReference<List<User>>{})
     * @param str 字符串
     * @param typeReference 泛型包装
     * @param <T> 泛型
     * @return T
     *
     */
    public static <T> T str2ObjList(String str, TypeReference<T> typeReference) {
        if (StrUtil.isBlank(str) || Objects.isNull(typeReference)) {
            log.error("parse string to object error : Params is null");
            return null;
        }
        try {
            return (T) (typeReference.getType().equals(String.class) ? str : objectMapper.readValue(str, typeReference));
        } catch (JsonProcessingException e) {
            log.warn("Parse String to Object error", e);
            return null;
        }
    }

    /**
     *  字符串转List等集合类型使用
     *         样例：
     *              JacksonUtil.string2ObjList(str,List.class,User.class)
     * @param str json字符串
     * @param collectionClazz 集合class对象
     * @param elementClazzs 元素class对象
     * @param <T> 返回的类型
     * @return T
     */
    public static <T> T str2ObjList(String str, Class<?> collectionClazz, Class<?>... elementClazzs) {
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(collectionClazz, elementClazzs);
        try {
            return objectMapper.readValue(str, javaType);
        } catch (IOException e) {
            log.warn("Parse String to Object error : {}" + e.getMessage());
            return null;
        }
    }

    /**
     * json字符串转为泛型 Map<String,Object>
     *     可根据类型自己创建不同的泛型Map
     * @param str json字符串
     * @return
     */
    public static Map str2Map(String str) {
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(Map.class, String.class, Object.class);
        try {
            return objectMapper.readValue(str, javaType);
        } catch (JsonProcessingException e) {
            e.printStackTrace();
            return null;
        }
    }

    /**
     * 构建json字符串
     * @return json Str
     */
    public static JacksonUtil.JsonBuilder builder() {
        return new JacksonUtil.JsonBuilder();
    }



    public static class JsonBuilder {
        private Map<String, Object> map = new HashMap<>();

        JsonBuilder(){}

        public JacksonUtil.JsonBuilder put(String key, Object value) {
            map.put(key, value);
            return this;
        }

        public String build() {
            ObjectMapper objectMapper = new ObjectMapper();

            try {
                objectMapper.writeValueAsString(this.map);
            } catch (JsonProcessingException e) {
                e.printStackTrace();
            }
            return "{}";
        }
    }
}