【高效开发插件】12 MapperUtils JackSon 工具类

迈不过友情╰ 2022-03-14 23:48 126阅读 0赞

import com.fasterxml.jackson.annotation.JsonInclude;
    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 java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    /**
     * Jackson 工具类
     * <p>Title: MapperUtils</p>
     * <p>Description: </p>
     */
    public class MapperUtils {
        private final static ObjectMapper objectMapper = new ObjectMapper();
    
        public static ObjectMapper getInstance() {
            return objectMapper;
        }
    
        /**
         * 转换为 JSON 字符串
         *
         * @param obj
         * @return
         * @throws Exception
         */
        public static String obj2json(Object obj) throws Exception {
            return objectMapper.writeValueAsString(obj);
        }
    
        /**
         * 转换为 JSON 字符串，忽略空值
         *
         * @param obj
         * @return
         * @throws Exception
         */
        public static String obj2jsonIgnoreNull(Object obj) throws Exception {
            ObjectMapper mapper = new ObjectMapper();
            mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
            return mapper.writeValueAsString(obj);
        }
    
        /**
         * 转换为 JavaBean
         *
         * @param jsonString
         * @param clazz
         * @return
         * @throws Exception
         */
        public static <T> T json2pojo(String jsonString, Class<T> clazz) throws Exception {
            objectMapper.configure(DeserializationFeature.ACCEPT_SINGLE_VALUE_AS_ARRAY, true);
            return objectMapper.readValue(jsonString, clazz);
        }
    
        /**
         * 字符串转换为 Map<String, Object>
         *
         * @param jsonString
         * @return
         * @throws Exception
         */
        public static <T> Map<String, Object> json2map(String jsonString) throws Exception {
            ObjectMapper mapper = new ObjectMapper();
            mapper.setSerializationInclusion(JsonInclude.Include.NON_NULL);
            return mapper.readValue(jsonString, Map.class);
        }
    
        /**
         * 字符串转换为 Map<String, T>
         */
        public static <T> Map<String, T> json2map(String jsonString, Class<T> clazz) throws Exception {
            Map<String, Map<String, Object>> map = objectMapper.readValue(jsonString, new TypeReference<Map<String, T>>() {
            });
            Map<String, T> result = new HashMap<String, T>();
            for (Map.Entry<String, Map<String, Object>> entry : map.entrySet()) {
                result.put(entry.getKey(), map2pojo(entry.getValue(), clazz));
            }
            return result;
        }
    
        /**
         * 深度转换 JSON 成 Map
         *
         * @param json
         * @return
         */
        public static Map<String, Object> json2mapDeeply(String json) throws Exception {
            return json2MapRecursion(json, objectMapper);
        }
    
        /**
         * 把 JSON 解析成 List，如果 List 内部的元素存在 jsonString，继续解析
         *
         * @param json
         * @param mapper 解析工具
         * @return
         * @throws Exception
         */
        private static List<Object> json2ListRecursion(String json, ObjectMapper mapper) throws Exception {
            if (json == null) {
                return null;
            }
    
            List<Object> list = mapper.readValue(json, List.class);
    
            for (Object obj : list) {
                if (obj != null && obj instanceof String) {
                    String str = (String) obj;
                    if (str.startsWith("[")) {
                        obj = json2ListRecursion(str, mapper);
                    } else if (obj.toString().startsWith("{")) {
                        obj = json2MapRecursion(str, mapper);
                    }
                }
            }
    
            return list;
        }
    
        /**
         * 把 JSON 解析成 Map，如果 Map 内部的 Value 存在 jsonString，继续解析
         *
         * @param json
         * @param mapper
         * @return
         * @throws Exception
         */
        private static Map<String, Object> json2MapRecursion(String json, ObjectMapper mapper) throws Exception {
            if (json == null) {
                return null;
            }
    
            Map<String, Object> map = mapper.readValue(json, Map.class);
    
            for (Map.Entry<String, Object> entry : map.entrySet()) {
                Object obj = entry.getValue();
                if (obj != null && obj instanceof String) {
                    String str = ((String) obj);
    
                    if (str.startsWith("[")) {
                        List<?> list = json2ListRecursion(str, mapper);
                        map.put(entry.getKey(), list);
                    } else if (str.startsWith("{")) {
                        Map<String, Object> mapRecursion = json2MapRecursion(str, mapper);
                        map.put(entry.getKey(), mapRecursion);
                    }
                }
            }
    
            return map;
        }
    
        /**
         * 将 JSON 数组转换为集合
         *
         * @param jsonArrayStr
         * @param clazz
         * @return
         * @throws Exception
         */
        public static <T> List<T> json2list(String jsonArrayStr, Class<T> clazz) throws Exception {
            JavaType javaType = getCollectionType(ArrayList.class, clazz);
            List<T> list = (List<T>) objectMapper.readValue(jsonArrayStr, javaType);
            return list;
        }
    
    
        /**
         * 获取泛型的 Collection Type
         *
         * @param collectionClass 泛型的Collection
         * @param elementClasses  元素类
         * @return JavaType Java类型
         * @since 1.0
         */
        public static JavaType getCollectionType(Class<?> collectionClass, Class<?>... elementClasses) {
            return objectMapper.getTypeFactory().constructParametricType(collectionClass, elementClasses);
        }
    
        /**
         * 将 Map 转换为 JavaBean
         *
         * @param map
         * @param clazz
         * @return
         */
        public static <T> T map2pojo(Map map, Class<T> clazz) {
            return objectMapper.convertValue(map, clazz);
        }
    
        /**
         * 将 Map 转换为 JSON
         *
         * @param map
         * @return
         */
        public static String mapToJson(Map map) {
            try {
                return objectMapper.writeValueAsString(map);
            } catch (Exception e) {
                e.printStackTrace();
            }
            return "";
        }
    
        /**
         * 将 JSON 对象转换为 JavaBean
         *
         * @param obj
         * @param clazz
         * @return
         */
        public static <T> T obj2pojo(Object obj, Class<T> clazz) {
            return objectMapper.convertValue(obj, clazz);
        }
    }