從json文件讀取json string或者自定義json string，將其轉(zhuǎn)為object。下面采用的object為map，根據(jù)map讀取json的某個(gè)數(shù)據(jù)，可以讀取第一級的數(shù)據(jù)name，后來發(fā)現(xiàn)想轉(zhuǎn)成JsonArray讀取”red“時(shí)沒撤了，只好用了其他方法。
最后用org.json包解決了（readJsonArray函數(shù)），有空再看看有沒有更好的辦法。
JSON文件如下：
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{ "name":"name", "id":"id", "color":[ {"red":"red","blue":"blue"}, {"white":"white"} ]} |
代碼如下：
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package com;import org.codehaus.jackson.map.ObjectMapper;import org.json.JSONArray;import org.json.JSONObject;import org.slf4j.Logger;import org.slf4j.LoggerFactory;import java.io.*;import java.util.Map;/** * Hello world! * */public class JsonAnalysis{ private static final Logger LOG = LoggerFactory.getLogger(JsonAnalysis.class); public static void main(String[] args) throws FileNotFoundException { String jsonString = "{\"address\":\"address\",\"name\":\"name\",\"id\":\"1\",\"email\":\"email\"}"; FileReader fileReader = new FileReader("E:\\JsonAnalysis\\src\\test.json"); String fileString = readFile(fileReader); //Json字符串轉(zhuǎn)java對象,比如轉(zhuǎn)為Map對象讀取其中數(shù)據(jù) Map map = null; Map mapFile = null; try { map = readValue(jsonString, Map.class); mapFile = readValue(fileString, Map.class); } catch (Exception e) { e.printStackTrace(); LOG.error("ReadValue occur exception when switch json string to map"); } System.out.println(map != null ? map.get("id") : null); if (mapFile==null){ LOG.info("Json map form file is empty"); return; } System.out.println(mapFile.get("name")); try { readJsonArray(fileString); } catch (Exception e) { e.printStackTrace(); } } //Json string to object private static <T> T readValue(String jsonStr, Class<T> valueType) throws Exception{ ObjectMapper objectMapper = new ObjectMapper(); try {// Object object = objectMapper.readValue(jsonStr,Object.class); return objectMapper.readValue(jsonStr,valueType); } catch (IOException e) { e.printStackTrace(); } return null; } //Read file and to string private static String readFile(FileReader fileReader){ BufferedReader bufferedReader = new BufferedReader(fileReader); StringBuilder fileStr = new StringBuilder(); try { String eachLine; while ((eachLine=bufferedReader.readLine())!=null){ fileStr.append(eachLine); } return fileStr.toString(); } catch (IOException e1) { e1.printStackTrace(); LOG.error("Occur exception when read file,file={}",fileReader); return null; } } //根據(jù)json string 獲取json array,讀取數(shù)據(jù)（ 注意該部分引用的是org.json 包） private static void readJsonArray(String jsonStr) throws Exception { JSONObject jsonObject = new JSONObject(jsonStr); JSONArray jsonArray = jsonObject.getJSONArray("color"); JSONObject jsonObject1 = jsonArray.getJSONObject(0); System.out.println(jsonObject1.get("red")); }} |
以上這篇Jackson將json string轉(zhuǎn)為Object,org.json讀取json數(shù)組的實(shí)例就是小編分享給大家的全部內(nèi)容了，希望能給大家一個(gè)參考，也希望大家多多支持服務(wù)器之家。
原文鏈接：http://www.cnblogs.com/ilovena/archive/2017/12/11/8023305.html
