Fastjson使用技巧

json格式化

#post请求json格式

{"results": [{
			"vin": "1888",
			"pushId": "40",
			"pushState": 1,
			"arrivalTime": "2018-03-10 21:02:22"
		}, {
			"vin": "03064",
			"pushId": "40",
			"pushState": 1,
			"arrivalTime": "2018-03-10 21:02:22"
		}
	]
}

• 现在想取得results里的内容:

Map map=JSON.parseObject(body,Map.class);
		String results=map.get("results");

• 会直接报错.错误为:

java.lang.ClassCastException: com.alibaba.fastjson.JSONArray cannot be cast to java.lang.String

• 正确写法为:

Map map=JSON.parseObject(body,new TypeReference>(){});
		String results=map.get("results");

---

##fastjson date时间格式化:

JSON.toJSONStringWithDateFormat(pushContent, "yyyy-MM-dd HH:mm:ss")

自动把Date时间格式为yyyy-MM-dd HH:mm:ss格式 .

package com.abupdate.carpush.bean;

import com.abupdate.carpush.common.BaseParams;
import com.fasterxml.jackson.annotation.JsonFormat;
import java.util.Date;
import java.util.List;

/**
 * @author allen
 * @date 20/03/2018
 */
public class PushContent {

	private String token;

	private List vins;

	private String content;

	private String pushId;

	@JsonFormat(shape = JsonFormat.Shape.STRING,pattern = BaseParams.TIME_PATTERN_FORMAT,timezone = "GMT+8")
	private Date endTime;

	public List getVins() {
		return vins;
	}

	public void setVins(List vins) {
		this.vins = vins;
	}

	public String getContent() {
		return content;
	}

	public void setContent(String content) {
		this.content = content;
	}

	public String getPushId() {
		return pushId;
	}

	public void setPushId(String pushId) {
		this.pushId = pushId;
	}

	public Date getEndTime() {
		return endTime;
	}

	public void setEndTime(Date endTime) {
		this.endTime = endTime;
	}

	public String getToken() {
		return token;
	}

	public void setToken(String token) {
		this.token = token;
	}

}

转换

POJO类型转string

TrainNoBO trainNoBO=new TrainNoBO();
String json= JSONObject.toJSONString(trainNoBO);

string转POJO

 TrainNoBO trainNoBO1 = JSON.parseObject(s, TrainNoBO.class);

取某一个字段

 JSONObject jsonObject = JSON.parseObject(s);
 String fromCity = jsonObject.getString("fromCity");

string转list

  List array= JSON.parseArray(a,String.class);

  for(String tmp: array){
        System.out.println(tmp);
   }