ObjectMapper工具类 json字符串和 对象之间转换。和对于 ObjectMapper的一些可选设置。

package com.itheima.utils;

import com.fasterxml.jackson.annotation.JsonInclude;
import com.fasterxml.jackson.core.type.TypeReference;
import com.fasterxml.jackson.databind.*;
import com.fasterxml.jackson.databind.ser.impl.SimpleFilterProvider;
import lombok.Builder;

import java.text.SimpleDateFormat;

public class JsonMapperUtil {
 
    private static ObjectMapper objectMapper = new ObjectMapper();
 
    static {
        //config
        objectMapper.disable(DeserializationFeature.FAIL_ON_UNKNOWN_PROPERTIES);//设置在反序列化时忽略在JSON字符串中存在，而在Java中不存在的属性
        objectMapper.configure(SerializationFeature.FAIL_ON_EMPTY_BEANS, false);//如果是空对象的时候,不抛异常
        objectMapper.setFilters(new SimpleFilterProvider().setFailOnUnknownId(false));
        objectMapper.setSerializationInclusion(JsonInclude.Include.NON_EMPTY);//属性为null的转换
        objectMapper.setDateFormat(new SimpleDateFormat("yyyy-MM-dd HH:mm:ss"));
    }
 
 
    /**
     * 对象转String
     * @param src
     * @param <T>
     * @return
     */
    public static <T> String obj2String(T src){
        if (null == src){
            return null;
        }
        try {
            return src instanceof String ? (String) src:objectMapper.writeValueAsString(src);
        } catch (Exception e) {
            return null;
        }
    }
 
    public static <T> T string2Obj(String src, TypeReference<T> typeReference){
        if(null == src || null == typeReference){
            return null;
        }
        try {
            return (T) (typeReference.getType().equals(String.class) ? src : objectMapper.readValue(src, typeReference));
        } catch (Exception e){
            return null;
        }
    }

    public static void main(String[] args) {
        SysAcl acl = SysAcl.builder().id(1).name("测试").remark("ceshi").build();
        String a = JsonMapperUtil.obj2String(acl);
        System.out.println(a);
        SysAcl sysAcl = JsonMapperUtil.string2Obj(a, new TypeReference<SysAcl>() {});
        System.out.println(sysAcl.toString());
    }

    @Builder
    public  class SysAcl{
        private  Integer id;
        private String name;
        private String remark;
    }

 }