jackson工具类-String转对象，String转List

- 日理万妓 2022-05-22 00:11 239阅读 0赞

工具类如下:

package com.xxxx.utils.json;
    
    import org.codehaus.jackson.JsonParser;
    import org.codehaus.jackson.map.ObjectMapper;
    import org.codehaus.jackson.map.annotate.JsonSerialize;
    import org.codehaus.jackson.map.ser.StdSerializerProvider;
    import org.codehaus.jackson.map.ser.std.NullSerializer;
    import org.codehaus.jackson.type.TypeReference;
    import org.slf4j.Logger;
    import org.slf4j.LoggerFactory;
    
    import java.io.IOException;
    import java.text.SimpleDateFormat;
    
    public class JsonUtil {
    
        private static final Logger log = LoggerFactory.getLogger(JsonUtil.class);
        private final static ObjectMapper objectMapper;
    
        static {
            StdSerializerProvider sp = new StdSerializerProvider();
            sp.setNullValueSerializer(NullSerializer.instance);
            objectMapper = new ObjectMapper(null, sp, null);
            objectMapper.configure(JsonParser.Feature.ALLOW_SINGLE_QUOTES, true);
            objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_FIELD_NAMES, true);
            objectMapper.configure(JsonParser.Feature.INTERN_FIELD_NAMES, true);
            objectMapper.configure(JsonParser.Feature.ALLOW_UNQUOTED_CONTROL_CHARS, true);
            objectMapper.setSerializationInclusion(JsonSerialize.Inclusion.NON_NULL);
            objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
        }
    
        public static ObjectMapper getObjectMapper() {
            return objectMapper;
        }
    
        /**
         * JSON字符串转换为Java泛型对象
         * 例1：String jsonStr = "[{\"id\":\"1234\",\"account\":\"admin\"}]";
         * List<UserInfo> list = JsonUtil.json2GenericObject(jsonStr, new TypeReference<List<UserInfo>>() {});
         * 例2：String jsonStr = "[\"1111\",\"2222\",\"3333\"]";
         * List<String> list = JsonUtil.json2GenericObject(jsonStr, new TypeReference<List<String>>() {});
         * @param <T> 转换泛型
         * @param jsonString JSON字符串
         * @param tr 需要转换的对象类型
         * @return Java泛型对象
         */
        public synchronized static <T> T json2GenericObject(String jsonString, TypeReference<T> tr) {
            if (jsonString != null && !("".equals(jsonString))) {
                try {
                    return (T) (tr.getType().equals(String.class) ? jsonString : objectMapper.readValue(jsonString, tr));
                } catch (Exception e) {
                    log.warn("json error:" + e.getMessage());
                }
            }
            return null;
        }
    
        /**
         * Java对象转Json字符串
         * @param object Java对象，可以是对象，数组，List,Map等
         * @return json 字符串
         */
        public synchronized static String toJson(Object object) {
            String jsonString = "";
            try {
                jsonString = objectMapper.writeValueAsString(object);
                if (log.isDebugEnabled()) {
                    log.debug(jsonString);
                }
            } catch (Exception e) {
                log.warn("json error:" + e.getMessage());
            }
            return jsonString;
        }
    
        /**
         * Json字符串转Java对象
         * @param jsonString json字符串
         * @param clazz java类
         * @return
         * @deprecated
         */
        public synchronized static Object json2Object(String jsonString, Class<?> clazz) {
            if (jsonString != null && !("".equals(jsonString))) {
                try {
                    return objectMapper.readValue(jsonString, clazz);
                } catch (Exception e) {
                    log.warn("json error:" + e.getMessage());
                }
            }
            return "";
        }
    
        /**
         * JSON字符串转java对象
         * @param <T> 转换泛型
         * @param jsonStr JSON字符串
         * @param clazz 类型
         * @return java对象
         */
        public synchronized static <T> T json2Java(String jsonStr, Class<T> clazz) {
            try {
                return objectMapper.readValue(jsonStr, clazz);
            } catch (IOException e) {
                log.warn("json error:" + e.getMessage());
                return null;
            }
        }
    }

使用方式如下:

String转对象
    xxxx data = JsonUtil.json2GenericObject(str, new TypeReference<xxxx>(){});
    String转List
    List<xxxx> valueList = JsonUtils.json2GenericObject(str, new TypeReference<List<xxxx>>(){});