Jackson

Jackson

工具方法

import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;
import com.fasterxml.jackson.databind.type.CollectionType;
import com.google.common.collect.Lists;
import com.google.common.collect.Maps;
import org.apache.commons.lang.StringEscapeUtils;
import org.apache.commons.lang3.StringUtils;
import java.io.IOException;
import java.text.DateFormat;
import java.text.ParseException;
import java.text.SimpleDateFormat;
import java.util.*;
import java.util.concurrent.ConcurrentHashMap;
import java.util.function.Function;
import java.util.function.Predicate;
import java.util.stream.Collectors;
import static com.fasterxml.jackson.databind.DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES;

    public static <T> T jsonToObject(String json, Class<T> classType) throws IOException {
        if (StringUtils.isBlank(json)) {
            return null;
        }
        ObjectMapper objectMapper = new ObjectMapper();
        objectMapper.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);
        return objectMapper.readValue(json, classType);
    }

    /**
     * json转Map
     *
     * @param json      json字符串
     * @param classType 数组中元素类型.Class
     * @return Map
     */
    public static <T> Map<String, Object> jsonToMap(String json, Class<T> classType) throws IOException {
        if (StringUtils.isBlank(json)) {
            return null;
        }
        ObjectMapper objectMapper = new ObjectMapper();
        //未知属性不序列化不报错
        objectMapper.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);
        Map<String, Object> map = Maps.newHashMap();
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(HashMap.class, String.class, classType);
        return objectMapper.readValue(json, javaType);

    }

    /**
     * json转List数组
     *
     * @param json      json字符串
     * @param classType 数组中元素类型.Class
     * @param        参数类型
     * @return List
     */
    public static <T> List<T> jsonToList(String json, Class<T> classType) throws IOException {
        if (StringUtils.isBlank(json)) {
            return null;
        }
        ObjectMapper objectMapper = new ObjectMapper();
        //未知属性反序列化不报错
        objectMapper.configure(FAIL_ON_UNKNOWN_PROPERTIES, false);

        List<T> list = Lists.newArrayList();
        CollectionType listType = objectMapper.getTypeFactory().constructCollectionType(ArrayList.class, classType);
        return objectMapper.readValue(json, listType);
    }

    public static String objectToJson(Object o) throws IOException {
        ObjectMapper objectMapper = new ObjectMapper();
        return objectMapper.writeValueAsString(o);
    }
        /**
     * 反转义 , 去除多余字符
     * @param text  字符串
     * @return
     */
    public static String unescapeString(String text){
        if (StringUtils.isBlank(text)){
            return "";
        }
        text = StringEscapeUtils.unescapeJavaScript(text);

        if (text.startsWith("\"")){
            text = text.substring(1);
        }
        if (text.endsWith("\"")){
            text = text.substring(0,text.length()-1);
        }
        text = text.replace("\\\\","");
        return text;
    }