FASTJSON 2.0 新版本

一、简介

       FASTJSON 2.0是FASTJSON项目的重要升级，目标是为下一个十年提供一个高性能的JSON库，同一套API支持JSON/JSONB两种协议，JSONPath是一等公民，支持全量解析和部分解析，支持Java服务端、客户端Android、大数据场景。

FASJTONS2 代码https://github.com/alibaba/fastjson2/releases/tag/2.0.1

JSONB格式文档https://github.com/alibaba/fastjson2/wiki/jsonb_format_cn

FASTJSON 2性能有了很大提升，具体性能数据看这里https://github.com/alibaba/fastjson2/wiki/fastjson_benchmark二、环境

        
        
            com.alibaba.fastjson2
            fastjson2
            2.0.1
        

三、代码

package com.dily.study.demo.test;

import com.alibaba.fastjson2.*;
import lombok.AllArgsConstructor;
import lombok.Data;

import java.nio.charset.StandardCharsets;
import java.util.Arrays;


public class FastJson2 {

    public static void main(String[] args) {
        
        String strObject = "{"id":123,"name":"dily"}";
        JSONObject jsonObject = JSON.parseObject(strObject);
        // 获取属性值  不同类型的值使用不同的get方法
        System.out.println(jsonObject.getIntValue("id"));
        // 123
        System.out.println(jsonObject.getString("name"));
        // dily

        
        String strArray = "[{"id":123,"name":"dily"},{"id":124,"name":"dily2"}]";
        JSONArray jsonArray = JSON.parseArray(strArray);
        // 获取数组中的对象  不同的类型使用不同的get方法
        System.out.println(jsonArray.getJSONObject(0));
        // {"id":123,"name":"dily"}
        System.out.println(jsonArray.getString(0));
        // {"id":123,"name":"dily"}

        
        @Data
        @AllArgsConstructor
        class Product {
            private int id;
            private String name;
        }

        Product product = new Product(123, "dily");
        String str1 = JSON.toJSONString(product);
        System.out.println(str1);
        // {"id":1,"name":"test"}
        String str2 = JSON.toJSONString(product, JSONWriter.Feature.BeanToArray);
        System.out.println(str2);
        // [1,"test"]

        
        byte[] utf8JSONBytes = JSON.toJSONBytes(product);
        System.out.println(Arrays.toString(utf8JSONBytes));
        // [123, 34, 105, 100, 34, 58, 49, 44, 34, 110, 97, 109, 101, 34, 58, 34, 116, 101, 115, 116, 34, 125]

        
        byte[] jsonbBytes = JSONB.toBytes(product);
        System.out.println(Arrays.toString(jsonbBytes));
        // [-90, 75, 105, 100, 1, 77, 110, 97, 109, 101, 77, 116, 101, 115, 116, -91]
        byte[] arrayJsonbBytes = JSONB.toBytes(product, JSONWriter.Feature.BeanToArray);
        System.out.println(Arrays.toString(arrayJsonbBytes));
        // [-106, 1, 77, 116, 101, 115, 116]

        
        Product product1 = JSON.parseObject(strObject, Product.class);
        System.out.println(product1);
        // Product(id=123, name=dily)

        
        byte[] utf8bytes = "{"id":123,"name":"dily"}".getBytes(StandardCharsets.UTF_8);
        Product product2 = JSON.parseObject(utf8bytes, Product.class);
        System.out.println(product2);
        // Product(id=123, name=dily)

        
        Product product3 = JSONB.parseObject(jsonbBytes, Product.class);
        System.out.println(product3);
        // Product(id=1, name=test)

        
        // 读取数据
        // strObject -> {"id":123,"name":"dily"}
        System.out.println(strObject);
        JSONReader reader = JSONReader.of(strObject); // 只能用一次，第二次使用必须重新赋值
        JSONPath idPath = JSONPath.of("$.id");
        JSONPath namePath = JSONPath.of("$.name");
        Object name = namePath.extract(reader);
        System.out.println(name);
        // dily
        reader = JSONReader.of(strObject);
        Object id = idPath.extract(reader);
        System.out.println(id);
        // 123

        // 读取 byte[] utf8Bytes
        JSONPath path = JSONPath.of("$.id"); // 缓存起来重复使用能提升性能
        JSONReader parser = JSONReader.of(utf8bytes);
        Object result1 = path.extract(parser);
        System.out.println(result1);
        // 123

        // 读取 byte[] jsonbBytes
        JSONReader jsonReader = JSONReader.ofJSONB(jsonbBytes); // 注意，这是利用ofJSONB方法
        Object result2 = path.extract(jsonReader);
        System.out.println(result2);
        // 123
    }

}