org.json与fastjson与gson的倾向于解析速度的性能测试

这篇文章是我2015-02-08写的 Android为啥使用org.json而不用gson,如何更好的测试和对比这两个东西,哪个大神能告诉我小萌头? 那篇文章的续篇.

首先,要PK的这三个都是json解析与生成的类库. 上次那篇文章可能写的太初级或有主观情绪在里面,导致没有人愿意帮我做出更好的指导. 我这次学了一点点专业级性能测试的皮毛,打算做客观的基准测试. 每一种基准测试都必须严格做出限定条件,得出足够窄的某一面的结论. 我这里限定了如下条件:

• 不比较这三个类库的易用性可维护性,尽管在我看来fastjson,gson比org.json好用好维护的多;
• 仅做解析json的速度测试,不做生成json的速度测试,不做期间消耗的内存,cpu相关的测试以及其他不相干的测试,有兴趣的可自行测试;
• 假定json字符串中所有的内容数据都能用的上且仅用一次. 因为org.json可能直接以”流”模式操作字符串,如果不需要用到所有内容数据,仅用两个字段,其速度可能优于另外两个,而如果内容数据需要保存到JavaBean中进行复用,看起来fastjson和gson要占便宜;
• 未考虑大文本json和json里含对象数组的情况;
• 限定在64位Ubuntu14.04和64位Windows7平台,Intel 酷睿4核,8G内存,Oracle Hotspot server VM mixed mode的JDK1.8.0的情况下;
• 这里的org.json指group: ‘org.json’,name: ‘json’,version: ‘20141113’,这里的fastjson指group: ‘com.alibaba’,name: ‘fastjson’,version: ‘1.2.5’,这里的gson指group: ‘com.google.code.gson’,name: ‘gson’,version: ‘2.3.1’;

要达到的几个测试目标有:

• 得出正确的几个类库解析速度数据和对比结论,这是总纲,事实上,还是不能得出十分精确的结论,但尽可能确保趋势是正确的,排除所有的干扰;
• 考虑到垃圾回收的干扰,尽可能减少测试区域中的对象创建以及指定较大的堆,目前使用-Xms1024m -Xmx1024m -Xss2m;
• 考虑到线程切换的干扰和锁的干扰,仅在单线程中运行,并未使用同步;
• 考虑到JIT编译干扰,记录解释执行的数据,加大测试次数(大于1000万),尽可能统计JIT编译后的平均数据. 当然可以指定-server -Xcomp直接测试编译后的速度;
• 考虑到jvm做逃逸跟踪分析时的性能影响,以及分析后动态优化措施的影响,包括锁消除,栈上分配对象,标量替换,去除无用代码和多余赋值,自动装箱拆箱消除等,使用大数量测试次数来平摊这种影响,不睬信javap反汇编代码执行流程,并且在使用-XX:+AggressiveOpts参数和不使用该参数各做若干次执行测试;

测试结果是fastjson > gson > org.json;

fastjson : (前面摘取: 189670,218408),(平均值摘取: 4170,4453);
gson: (前面摘取: 71434,62812),(平均值摘取: 6427,5033);
org.json: (前面摘取: 87035,89498),(平均值摘取: 9641,9652);

以下是测试代码:
(JsonTest.java)

import com.alibaba.fastjson.JSON;
import com.google.gson.Gson;
import org.json.JSONObject;

public class JsonTestAgain {
    private static final Gson gson = new Gson();
    private static final int iterTimes = 20000000;

    private static long avgTime = 0L;

    public static void main(String[] args) {
        String json = "{"id":109394012,"name":"zhangsan","school":"renmindaxue","age":24,"isFemale":false,"area":"beijing","city":"beijing","address":"changping","phone":"13100049348","email":"xxx@163.com","isMarried":true,"beginDate":"2009-01-01","beginCompany":"pingan","height":178,"weight":200,"style":1,"leaveDate":"2010-01-01","mrRight":{"id":1093079412,"name":"meinv","age":21,"isFemale":true,"phone":"13149348000","email":"zzz@163.com","beginDate":"2007-09-01","beginCompany":"nuoya","height":160,"weight":100,"style":2,"leaveDate":"2012-11-01"}}";

        JohnTestData data = new JohnTestData();
        data.mrRight = new JohnTestData();

        for (int i = 0; i < 1000; i++) {
            System.out.println(uSEOrgJson(json,data));
        }
        avgTime = uSEOrgJson(json,data);
        for (int i = 0; i < iterTimes; i++) {
            avgTime += uSEOrgJson(json,data);
            avgTime = avgTime / 2;
        }
        System.out.println("============================");
        System.out.println(avgTime);
    }

    private static long uSEOrgJson(String json,JohnTestData right) {
        long start = System.nanoTime();
        JSONObject left = new JSONObject(json);
        right.address = left.getString("address");
        right.age = left.getInt("age");
        right.area = left.getString("area");
        right.beginCompany = left.getString("beginCompany");
        right.beginDate = left.getString("beginDate");
        right.city = left.getString("city");
        right.email = left.getString("email");
        right.height = left.getInt("height");
        right.id = left.getLong("id");
        right.isFemale = left.getBoolean("isFemale");
        right.isMarried = left.getBoolean("isMarried");
        right.leaveDate = left.getString("leaveDate");
        right.name = left.getString("name");
        right.phone = left.getString("phone");
        right.weight = left.getInt("weight");
        right.school = left.getString("school");
        right.style = left.getInt("style");
        JSONObject object = left.getJSONObject("mrRight");
        right.mrRight.address = object.getString("address");
        right.mrRight.age = object.getInt("age");
        right.mrRight.area = object.getString("area");
        right.mrRight.beginCompany = object.getString("beginCompany");
        right.mrRight.beginDate = object.getString("beginDate");
        right.mrRight.city = object.getString("city");
        right.mrRight.email = object.getString("email");
        right.mrRight.height = object.getInt("height");
        right.mrRight.id = object.getLong("id");
        right.mrRight.isFemale = object.getBoolean("isFemale");
        right.mrRight.isMarried = object.getBoolean("isMarried");
        right.mrRight.leaveDate = object.getString("leaveDate");
        right.mrRight.name = object.getString("name");
        right.mrRight.phone = object.getString("phone");
        right.mrRight.weight = object.getInt("weight");
        right.mrRight.school = object.getString("school");
        right.mrRight.style = object.getInt("style");
        right.mrRight.mrRight = null;
        return System.nanoTime() - start;
    }

    private static long useFastjson(String json,JohnTestData right) {
        long start = System.nanoTime();
        JohnTestData left = JSON.parSEObject(json,JohnTestData.class);
        right.address = left.address;
        right.age = left.age;
        right.area = left.area;
        right.beginCompany = left.beginCompany;
        right.beginDate = left.beginDate;
        right.city = left.city;
        right.email = left.email;
        right.height = left.height;
        right.id = left.id;
        right.isFemale = left.isFemale;
        right.isMarried = left.isMarried;
        right.leaveDate = left.leaveDate;
        right.name = left.name;
        right.phone = left.phone;
        right.weight = left.weight;
        right.school = left.school;
        right.style = left.style;
        right.mrRight = left.mrRight;
        return System.nanoTime() - start;
    }

    private static long useGson(String json,JohnTestData right) {
        long start = System.nanoTime();
        JohnTestData left = gson.fromJson(json,JohnTestData.class);
        right.address = left.address;
        right.age = left.age;
        right.area = left.area;
        right.beginCompany = left.beginCompany;
        right.beginDate = left.beginDate;
        right.city = left.city;
        right.email = left.email;
        right.height = left.height;
        right.id = left.id;
        right.isFemale = left.isFemale;
        right.isMarried = left.isMarried;
        right.leaveDate = left.leaveDate;
        right.name = left.name;
        right.phone = left.phone;
        right.weight = left.weight;
        right.school = left.school;
        right.style = left.style;
        right.mrRight = left.mrRight;
        return System.nanoTime() - start;
    }
}

(JohnTestData.java)

public final class JohnTestData {
    public long id;
    public String name;
    public String school;
    public int age;
    public boolean isFemale;
    public String area;
    public String city;
    public String address;
    public String phone;
    public String email;
    public boolean isMarried;
    public String beginDate;
    public String beginCompany;
    public int height;
    public int weight;
    public int style;
    public String leaveDate;
    public JohnTestData mrRight;
}

注: 这里JohnTestData left里的mrRight不能再指向left,即如果出现循环引用,gson和fastjson可能发生异常.