jackson工具类(JsonUtil )

 

springboot用的就是这个

import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.DeserializationFeature;
import com.fasterxml.jackson.databind.JavaType;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.io.InputStream;
import java.io.InputStreamReader;
import java.io.Reader;
import java.util.List;

public class JsonUtil {
    private static ObjectMapper objectMapper = new ObjectMapper();
    static {
        objectMapper.configure(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES, false);// 允许pojo中有在json串中不存在的字段
        objectMapper.configure(JsonParser.Feature.ALLOW_COMMENTS, true);// 允许有注释
    }
    
    public static <T>T parseObject(InputStream inputStream, Class<T> tClass) {
        Reader reader = new InputStreamReader(inputStream);
        try {
            return objectMapper.readValue(reader, tClass);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static <T>T parseObject(String json,Class<T> tClass){
        try {
            return objectMapper.readValue(json,tClass);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static String toJsonString(Object object){
        try {
            return objectMapper.writeValueAsString(object);
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

    public static <T>List<T> parseList(String json,Class<T> tClass) {
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(List.class, tClass);
        try {
            List<T> list = objectMapper.readValue(json, javaType);
            return list;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }
    /**
     * @param outClass 外层对象
     * @param inClass 泛型
     */
    public static <T>T parseObject(String json,Class<T> outClass,Class inClass) {
        JavaType javaType = objectMapper.getTypeFactory().constructParametricType(outClass, inClass);
        try {
            T o = objectMapper.readValue(json, javaType);
            return o;
        } catch (IOException e) {
            throw new RuntimeException(e);
        }
    }

}