廖雪峰Java14Java操作XML和JSON-2JSON-2处理JSON

解析JSON
JSR 353 API
常用的第三方库
Jackson
gson
fastjson

Jackson:
提供了读写JSON的API
JSON和JavaBean可以互相转换
可食用Annotation定制序列化和反序列化

Jackson初步使用

        <dependency>
            <groupId>com.fasterxml.jackson.core</groupId>
            <artifactId>jackson-databind</artifactId>
            <version>2.9.0</version>
        </dependency>
        <dependency>
            <groupId>com.fasterxml.jackson.datatype</groupId>
            <artifactId>jackson-datatype-jsr310</artifactId>
            <version>2.9.0</version>
        </dependency>

package com.feiyangedu.sample.pop3;

import com.fasterxml.jackson.core.JsonProcessingException;
import com.fasterxml.jackson.databind.JsonNode;
import com.fasterxml.jackson.databind.ObjectMapper;

import java.io.IOException;
import java.text.SimpleDateFormat;
import java.util.Date;
import java.util.TimeZone;

public class ParseJsonTest {
    public static void main(String[] args) {
        String data = "{\"type\":2,\"range\":1,\"start\":1368417600,\"end\":1368547140,"
                + "\"cityName\":\"天津\",\"companyIds\":[\"12000001\"],\"companyNames\":[\"天津\"],"
                + "\"12000001\":{\"data\":[47947,48328,48573,48520],"
                + "\"timestamps\":[1368417600,1368417900,1368418200,1368418500]}}";
        String data2 = parseJson(data);
        System.out.println(data2);
    }
    public static String parseJson(String data){
        StringBuffer buffer = new StringBuffer();
        try{
            ObjectMapper mapper = new ObjectMapper();
            JsonNode rootNode = mapper.readTree(data);
            int type = rootNode.path("type").asInt();
            int range = rootNode.path("range").asInt();
            long start = rootNode.path("start").asLong();
            long end = rootNode.path("end").asLong();
            String cityName = rootNode.path("cityName").asText();
            SimpleDateFormat sdf = new SimpleDateFormat("yyyyMMddHHmm");
            sdf.setTimeZone(TimeZone.getTimeZone("GMT+8"));
            String str = "类型(type):"+type+"\r\n"+"范围(range):"+range+"\r\n"+
                    "开始时间(start):"+sdf.format(new Date(start*1000))+"\r\n"+"结束时间(end):"+sdf.format(new Date(end*1000))+"\r\n"+
                    sdf.format(new Date(end*1000))+"\r\n"+"城市名称(cityName):"+cityName;
            buffer.append(str);
            JsonNode companyIds = rootNode.path("companyIds");
            JsonNode companyNames = rootNode.path("companyNames");
            for(int i=0;i<companyIds.size();i++){
                String companyId = companyIds.get(i).asText();
                String companyName = companyNames.get(i).asText();
                JsonNode infoNode = rootNode.path(companyId);
                JsonNode dataNode = infoNode.path("data");
                JsonNode timestampsNode = infoNode.path("timestamps");
                buffer.append("\r\n{\r\n 公司ID(companyId):"+companyId+"\r\n 公司名称(companyName):"+companyName+"\r\n"+"data:");
                for(int j=0;j<dataNode.size();j++){
                    long dataValue = dataNode.get(j).asLong();
                    buffer.append(dataValue+",");
                }
                buffer.append("\r\n timestamp:");
                for(int k=0;k<timestampsNode.size();k++){
                    long timeValue = timestampsNode.get(k).asLong();
                    buffer.append(sdf.format(new Date(timeValue*1000))+",");
                }
                buffer.append("\r\n}\r\n");
            }
        }catch (JsonProcessingException e){
            e.printStackTrace();;

        }catch (IOException e){
            e.printStackTrace();
        }
        return buffer.toString();
    }
}

总结：
Jackson提供了读写JSON和JavaBean的互相转换
可使用Annotation定制序列化和反序列化

来源：https://www.cnblogs.com/csj2018/p/11397742.html