Java 微信公众号导出所有粉丝(openId)

由于公众号换了公司主体，需要做迁移，玩家的openId数据需要做处理。

(我是按我要的json格式，将粉丝导成了1万条数据的一个json文件)

文件格式：

{
    "info":[
        {"openId":"ogVous494ltuNmO4zHb1seHeGLSk"}
    ]
}

package exportFansFromPublic;

import java.io.FileWriter;
import java.io.PrintWriter;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
import com.alibaba.fastjson.JSON;
import com.alibaba.fastjson.JSONArray;
import com.alibaba.fastjson.JSONObject;
import com.odao.weixin.api.support.AccessTokenKit;
import com.odao.weixin.api.support.HttpKit;

/**
 * 导出公众号粉丝
 * @author wangfj
 */
public class ExportFansFromPublic {
    @SuppressWarnings({ "unchecked", "static-access","rawtypes"})
    public static void main(String[] args) throws Exception {
        String token = AccessTokenKit.getTokenNew("appId", "app秘钥");
        String accesstoken = (String) ((Map) JSON.parseObject(token, Map.class)).get("access_token");
        Map<String,String> params = new HashMap<String,String>();
        params.put("access_token", accesstoken);
        String nextOpenId = "";
        for(int i=1;i<=50;i++){ //我这了定的50，是根据公众号粉丝数量来的，一个文件一万条，你们自己算
            if(!"".equals(nextOpenId)){
                params.put("next_openid", nextOpenId);
            }
            //根据appId,appSecret获取数据粉丝openId(1次1万条)
            //格式：{"data"：{"openid":["oneOpenId,twoOpenId"]},"next_openid":"theNextOpenId"}
            try{
                String data = HttpKit.get("https://api.weixin.qq.com/cgi-bin/user/get",params);
                JSONObject json = (JSONObject) JSONObject.parse(data);
                String openId = json.get("data").toString();

                JSONObject open = (JSONObject) JSONObject.parse(openId);
                String openIds = open.get("openid").toString();
                JSONArray arr= JSONObject.parseArray(openIds);

                List<String> list = arr.toJavaObject(arr,  List.class);

                nextOpenId = writerJson(list,i);
            }catch(Exception e){
                System.out.println("导出完毕");
                break;
            }
        }
    }

    public static String writerJson(List<String> list,int fileName){
        String nextOpenId = "";
        FileWriter fw = null;
        PrintWriter out = null;
        try {
            // 指定生成txt的文件路径
            fw = new FileWriter("C:/Users/admin/Desktop/fan/"+fileName+".json");
            out = new PrintWriter(fw);
            out.println("{");
            out.println("\t\"info\":[");
            for(int i=0;i<list.size();i++){
                if(i!=list.size()-1){
                    out.println("\t\t{\"openId\":\""+list.get(i)+"\"},");
                }else{
                    nextOpenId = list.get(i);
                    out.println("\t\t{\"openId\":\""+list.get(i)+"\"}");
                }
            }
            out.println("\t]");
            out.println("}");
        } catch (Exception e) {
            e.printStackTrace();
        } finally {
            try {
                out.close();
                fw.close();
                out.flush();  // 由于此处用到了缓冲流，如果数据量过大，不进行flush操作，某些数据将依旧  存在于内从中而不会写入文件，此问题一定要注意
            } catch (Exception e) {
                e.printStackTrace();
            }
        }
        return nextOpenId;
    }
}