从文本文件中读取多个JSON对象 [英] Read Multiple JSON object from a Text File

问题描述

我的问题类似于此处。
几点：

My Question is similar to what has been asked here . few points :

1. 我无法更改格式。 （没有逗号被添加等）


2. 这基本上是一个包含1000个Json对象的巨大.txt文件。


3. 我的Json对象很大。

这就是我现在正在做的事情：

This is what I am doing right now :

    FileReader fileReader = new FileReader(fileName);
        BufferedReader reader = new BufferedReader(fileReader);
        String data = "";
        while((data = reader.readLine()) != null){
            ObjectMapper mapper = new ObjectMapper();
            Map<String,String> map = mapper.readValue(data, Map.class);
        }

目前我正在使用Jackson，理想情况下我想从中读取一个Json对象一次解压文件，然后转到下一个文件。我需要从这些Json对象中统计出唯一的id号，并执行更多操作。最好一一阅读。

Currently I am using Jackson and Ideally I would like to read one Json Object from the file at a time, Parse it and then move on to the next one. I need to count let say unique number of id's from these Json object and do more operations. It will be best to read them one by one.

杰克逊是未来最好的方式吗？
这是一个解析巨大Json的好例子，但它只处理每个文件一个对象。我的文件有巨大的Jsons（其中有1000个）。

Is jackson would be the best way going forward ? This is a good example of parsing huge Json, But it deals with only one object per file. My file has huge Jsons (1000s of them).

推荐答案

这是一个适合我的杰克逊例子。我在单个json文件中有数千个json对象（令牌）。此代码将遍历文件读取每个令牌并打印它的序列。

Here is a Jackson example that works for me. I have thousands json objects (tokens) in a single json file. This code will iterate through the file read each token and print it's serial.

必需的导入：

Required imports:

import com.fasterxml.jackson.core.JsonFactory;
import com.fasterxml.jackson.core.JsonParser;
import com.fasterxml.jackson.databind.ObjectMapper;

使用Jackson从 FileInputStream ：

Using Jackson to read multiple json objects from FileInputStream:

try (FileInputStream fis = new FileInputStream("D:/temp/tokens.json")) {
        JsonFactory jf = new JsonFactory();
        JsonParser jp = jf.createParser(fis);
        jp.setCodec(new ObjectMapper());
        jp.nextToken();
        while (jp.hasCurrentToken()) {
            Token token = jp.readValueAs(Token.class);
            jp.nextToken();
            System.out.println("Token serial "+token.getSerialNumber());
        }
    }

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