package cn.itwx.mybatis.common;import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.ObjectMapper;
//import com.sun.istack.internal.Nullable;
import lombok.AllArgsConstructor;
import lombok.Data;
import lombok.NoArgsConstructor;
import org.slf4j.Logger;
import org.slf4j.LoggerFactory;
import org.springframework.lang.Nullable;import java.io.IOException;
import java.util.List;
import java.util.Map;/*** @author: qxy* @create: 2018-04-24 17:20**/
public class JsonUtils {public static final ObjectMapper mapper = new ObjectMapper();private static final Logger logger = LoggerFactory.getLogger(JsonUtils.class);/*** 将对象转换成json格式* @param obj* @return*/@Nullablepublic static String serialize(Object obj) {if (obj == null) {return null;}if (obj.getClass() == String.class) {return (String) obj;}try {return mapper.writeValueAsString(obj);} catch (JsonProcessingException e) {logger.error("json序列化出错：" + obj, e);return null;}}/*** 将json转换成对象的格式* @param json* @param tClass* @param <T>* @return*/@Nullablepublic static <T> T parse(String json, Class<T> tClass) {try {return mapper.readValue(json, tClass);} catch (IOException e) {logger.error("json解析出错：" + json, e);return null;}}/*** 将一个json转换成list* @param json* @param eClass* @param <E>* @return*/@Nullablepublic static <E> List<E> parseList(String json, Class<E> eClass) {try {return mapper.readValue(json, mapper.getTypeFactory().constructCollectionType(List.class, eClass));} catch (IOException e) {logger.error("json解析出错：" + json, e);return null;}}/*** 将json解析成map* @param json* @param kClass* @param vClass* @param <K>* @param <V>* @return*/@Nullablepublic static <K, V> Map<K, V> parseMap(String json, Class<K> kClass, Class<V> vClass) {try {return mapper.readValue(json, mapper.getTypeFactory().constructMapType(Map.class, kClass, vClass));} catch (IOException e) {logger.error("json解析出错：" + json, e);return null;}}/*** 解析复杂类型的json串，适用以上所有的格式* @param json* @param type* @param <T>* @return*/@Nullablepublic static <T> T nativeRead(String json, TypeReference<T> type) {try {return mapper.readValue(json, type);} catch (IOException e) {logger.error("json解析出错：" + json, e);return null;}}
}

public class JsonUtils {......//省去上面的封装方法//内部类@Data   //次注解可以省去类中的set\get方法@NoArgsConstructor//注解无参构造@AllArgsConstructor//有参构造static class User{String name;int age;}
//定义的主方法public static void main(String[] args) {User user = new User("lisi",23);//json序列化：将对象转换为json串String json = serialize(user);System.out.println("json="+json);//json反序列化：将json串转换成对象User parse = parse(json, User.class);System.out.println("user=" + parse);//将json转换成对象listString json = "[12,23,63,64]";List<Integer> integers = parseList(json, Integer.class);System.out.println("list="+integers);String userJson = "[{\"name\":\"lisi\",\"age\":21},{\"name\":\"ahua\",\"age\":32},{\"name\":\"llk\",\"age\":23}]";//自定义JOSNUtil工具类List<User> users = parseList(userJson, User.class);System.out.println("users=" + users);//使用JSON类List<User> userList = JSON.parseArray(userJson, User.class);System.out.println("userList =" + userList);//使用JSON的子类，JSONArrayList<User> list = JSONArray.parseArray(userJson, User.class);System.out.println("List = "+ list);//将json转换成map//language=JSONString json = "{\"name\":\"Jack\",\"age\":\"23\"}";Map<String, String> map = parseMap(json, String.class, String.class);System.out.println("map:"+map);//json串为map复杂类型//language=JSONString json = "[{\"name\":\"ROSE\",\"age\":\"32\"},{\"name\":\"jack\",\"sex\":\"m\"}]";List<Map<String, String>> maps = nativeRead(json, new TypeReference<List<Map<String, String>>>() {});//匿名内部类//循环Listfor (Map<String ,String> map : maps){System.out.println("map="+map);}
}