json转换工具类

深藏阁楼爱情的钟 2022-05-16 10:56 248阅读 0赞

package com.tent.springboot.controller;
    
    import java.io.IOException;
    import java.io.StringWriter;
    import java.util.ArrayList;
    import java.util.HashMap;
    import java.util.List;
    import java.util.Map;
    
    import com.fasterxml.jackson.core.JsonFactory;
    import com.fasterxml.jackson.core.JsonGenerator;
    import com.fasterxml.jackson.core.type.TypeReference;
    import com.fasterxml.jackson.databind.ObjectMapper;
    import org.springframework.stereotype.Controller;
    
    import java.util.Map;
    
    public class jsonUtils {
    
        private static final ObjectMapper OBJECT_MAPPER = new ObjectMapper();
        private  static  final JsonFactory JSON_FACTORY = new JsonFactory();
    
        /**
         * jsonToMap
         * @param jsonStr
         * @param clazz
         * @param <T>
         * @return
         */
        public static <T>Map<String, T> jsonToMap(String jsonStr, Class<T>  clazz){
            Map<String, T> map = new HashMap<>();
            try {
                map = OBJECT_MAPPER.readValue(jsonStr,
                        new TypeReference<Map<String, T>>() {
                        });
            } catch (IOException e) {
                e.printStackTrace();
            }
            return map;
        }
    
        /***
         * jsonToList
         * @param jsonStr
         * @param clazz
         * @param <T>
         * @return
         * @throws IOException
         */
        public static <T> List<T> jsonToList(String jsonStr, Class<T> clazz)
                throws IOException {
            List<T> list = new ArrayList<>();
            try {
                list = OBJECT_MAPPER.readValue(jsonStr,
                        new TypeReference<List<T>>() {
                        });
            } catch (IOException e) {
                e.printStackTrace();
            }
            return list;
        }
    
        /***
         * mapToJson
         * @param map
         * @return
         */
        public static String mapToJson(Map<String, Object> map) {
            StringWriter sw = new StringWriter();
            JsonGenerator jg;
            try {
                jg = JSON_FACTORY.createGenerator(sw);
                jg.useDefaultPrettyPrinter();
                OBJECT_MAPPER.writeValue(jg, map);
            } catch (IOException e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return sw.toString();
        }
    
        /**
         * objectToJson
         * @param obj
         * @return
         */
        public static String objectToJson(Object obj) {
            StringWriter sw = new StringWriter();
            JsonGenerator jg;
            try {
                jg = JSON_FACTORY.createGenerator(sw);
                jg.useDefaultPrettyPrinter();
                OBJECT_MAPPER.writeValue(jg, obj);
            } catch (IOException e) {
                e.printStackTrace();
            }
            return sw.toString();
        }
    
        /**
         * jsonToObject
         * @param json
         * @param clazz
         * @param <T>
         * @return
         */
        public static <T> T jsonToObject(String json, Class<T> clazz) {
            T result = null;
            try {
                result = OBJECT_MAPPER.readValue(json, clazz);
            } catch (Exception e) {
                // TODO Auto-generated catch block
                e.printStackTrace();
            }
            return result;
        }
    }