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借鉴原文章

https://www.cnblogs.com/sirui888/p/4749991.html

直接用对象转json，会出现对象名在{}前面，然后我结合了自己的业务逻辑，选取了部分属性，拼接，和{

public String findByCid(@RequestParam("cid")Integer cid,@RequestParam("wx_userid")Integer wx_userid) throws Exception{

        StringBuilder json = new StringBuilder();
        json.append("[");
        List<Record> records = recordService.findByCid(wx_userid,cid);
        if(records != null && records.size() >0){
            for(Record record:records ){
                json.append("{");
                json.append(record.getId());
                json.append(",");
                json.append(record.getTitle());
                json.append(",");
                json.append(record.getContent());
                json.append(",");
                json.append(record.getCreateTimeStr());
                json.append("},");
            }
            json.setCharAt(json.length() - 1, ']');
        }else{
            json.append("]");
        }
        System.out.println(json);
        System.out.println(json);
        return json.toString();
    }

结果是这样



但是我又发现，小程序端的json数据，需要有键值对的，所以我又改进了一下，给字符串加上了引号

 for(Record record:records ){
                json.append("{id:");
                json.append(record.getId());
                json.append(",title:\"");
                json.append(record.getTitle());
                json.append("\",content:\"");
                json.append(record.getContent());
                json.append("\",createTime:\"");
                json.append(record.getCreateTimeStr());
                json.append("\"},");
}

结果打印出来的是这样：

[{id:17,title:"asdfasdf",content:"sfasdf",createTime:"2020-11-29 13:57:52"},
{id:18,title:"112",content:"123",createTime:"2020-11-29 13:59:36"},
{id:19,title:"sdaf",content:"sadf",createTime:"2020-11-29 14:15:44"}]

但是小程序不识别这json格式，必须要标准的json格式，然后有在key值加上冒号

 for(Record record:records ){
                json.append("{\"id\":");
                json.append(record.getId());
                json.append(",\"title\":\"");
                json.append(record.getTitle());
                json.append("\",\"content\":\"");
                json.append(record.getContent());
                json.append("\",\"createTime\":\"");
                json.append(record.getCreateTimeStr());
                json.append("\"},");
            }

微信小程序端，wxml页面也可以获取data数组



java后台打印是这组数据

[{"id":17,"title":"asdfasdf","content":"sfasdf","createTime":"2020-11-29 13:57:52"},
{"id":18,"title":"112","content":"123","createTime":"2020-11-29 13:59:36"},
{"id":19,"title":"sdaf","content":"sadf","createTime":"2020-11-29 14:15:44"}]

过几天我再尝试一下使用map集合看行不行。