FastJSON 原理剖析 以及 和 Jackson的对比 who is the most fast!

FastJSON定义: FastJSON是一个阿里巴巴内部人员开发的,用于JSON对象和普通类对象互相转换的库。号称性能超越Jackson,今天我们就来看看,阿里巴巴大牛 vs Tatu Saloranta,到底 who is the most awesome!


FastJSON原理: 

-对象 to JSON :利用反射找到对象类的所有Get方法,然后把"get"去掉,小写化,作为JSON的每个key值,如 getA  对应的key值为 a,而与真实的类成员名无关。

-JSON to  pojo :先同样通过反射找到对象类所有的Set方法,然后使用无参数构造函数(所以一定要有无参数的构造函数)新建一个类对象,从JSON字符串中取出一个key 如 a,先大写化为A,那么从所有Set方法中找到 SetA(),然后进行赋值。 如果找不到 setA (seta也不行),那么该值被忽略,也不报错。


Jackson 的原理和FastJson一致,但是在 JSON to Java pojo的步骤中,做了更加科学的check,因而能识别seta这样的小写。但是如果getA 和geta都找不到,则会抛出异常(除非把a设置为忽略)。

其他的步骤原理和FastJSON类似。


测试验证代码:

package jar;

import com.alibaba.fastjson.JSON;

public class Test{
	
	
	private int aaa=0;
	private String bbb = "000";
	
	
	
	public Test() {
		// TODO Auto-generated constructor stub
		aaa = 1;
		bbb = "111";
		System.out.println(" default construct function is called!!!");
	}
	
	public Test(int a ,String b) {
		// TODO Auto-generated constructor stub
		aaa = a;
		bbb = b;
		System.out.println("construct 2 function is called!!!");
	}
	

	public int getA() {
		return aaa;
	}


	public void seta(int a)
	{
		this.aaa =a;
	}
	
	public String getB() {
		return bbb;
	}

	
	
	
	 //test
	 public static void main(String[] args) throws Exception  
	 {     	 
		 
		   Test test =new Test(2,"222");
		   String code =  JSON.toJSONString(test);
		   System.out.println(code);
		   Test reverse = JSON.parseObject(code,Test.class);

		   System.out.println(reverse.getA());
		   System.out.println(reverse.getB());
	 }

}


下面是对 FastJson 和 Jackson  (pojo to json-编码) 以及 (json to pojo-解码)以及综合(编码+解码) 在不同成员数量 下 ,不同循环次数的耗时(ns纳秒)对比。


//         code + decode -----------------------------------------------------
//         10000  - 23 members
//		   Jackson :235750737 ns
//		   FastJSON:347795550 ns
//         10000  - 2 members
//		   Jackson :164173126 ns
//		   FastJSON:159078284 ns
		   
		   
//	       100000 - 23 members
//		   Jackson :1004902734 ns
//		   FastJSON:1689072614 ns
//	       100000 - 2 members 
//		   Jackson :392344461 ns
//		   FastJSON:299521240 ns
		   
// 	       1000000 - 23 members
//		   Jackson :8547741285 ns
//		   FastJSON:15377369425 ns
// 	       1000000 - 2 members
//		   Jackson :2581267623 ns
//		   FastJSON:1591827729 ns
		   
//         code only -------------------------------------------------------
//         10000  - 23 members
//		   Jackson :115036100 ns
//		   FastJSON:158681243 ns
//         10000  - 2 members
//		   Jackson :87886170 ns
//		   FastJSON:103086025 ns
		   
		   
//	       100000 - 23 members
//		   Jackson :417539325 ns
//		   FastJSON:349358062 ns
//	       100000 - 2 members 
//		   Jackson :185865488 ns
//		   FastJSON:144893485 ns
		   
// 	       1000000 - 23 members
//		   Jackson :3384171740 ns
//		   FastJSON:2200190119 ns
// 	       1000000 - 2 members
//		   Jackson :1193815955 ns
//		   FastJSON:568776506 ns
		   
		   
//         decode only -------------------------------------------------------
//         10000  - 23 members
//		   Jackson :122597862 ns
//		   FastJSON:183567261 ns
//         10000  - 2 members
//		   Jackson :75418145 ns
//		   FastJSON:47832689 ns
		   
		   
//	       100000 - 23 members
//		   Jackson :497670344 ns
//		   FastJSON:1254994458 ns
//	       100000 - 2 members 
//		   Jackson :165368101 ns
//		   FastJSON:117555618 ns
		   
// 	       1000000 - 23 members
//		   Jackson :4189147981 ns
//		   FastJSON:12004873228 ns
// 	       1000000 - 2 members
//		   Jackson :999578584 ns
//		   FastJSON:863444723 ns



结论:

编码(pojo to json):  当循环数量较小时,FastJSON的性能 低于 JackSON;

    当循环数量越大时,FastJSON的性能开始超过Jackson;


解码( json to pojo):当成员数量越大时,FastJSON的相对性能越差,JackSON的相对性能则越好; 

   当成员数量越小时,FastJSON的性能越好。


综合(编码+解码): 当成员变量数量越大时,Jackson 获胜。无关于循环数量。 

当成员变量数量越小时,FastJSON获胜。


一般情况下,系统中的循环数量一般不会大的惊人,应该是偏小的。而成员变量变多,是一个企业级系统常见的情况。

SO, who is the most fast or best? 我就不点出了。

。。。

Whatever, 两个JSON框架都是很棒的。而且本人很喜欢FastJSON的易用性,干净。 

有时间,有兴趣的可以继续研究研究FastJSON在多成员变量解码时的劣势是什么原因导致的。

付上测试代码:

package jar;

import java.io.StringWriter;

import org.codehaus.jackson.JsonEncoding;
import org.codehaus.jackson.JsonGenerator;
import org.codehaus.jackson.map.ObjectMapper;

import com.alibaba.fastjson.JSON;

public class Test{
	
	
	
	private int aaa=0;
	private String bbb = "000";

	private String c1 = "000";
	private String c2 = "000";
	private String c3 = "000";
	private String c4 = "000";
	private String c5 = "000";
	private String c6 = "000";
	private String c7 = "000";
	private String c8 = "000";
	private String c9 = "000";
	private String c10 = "000";
	private String c11 = "000";
	private String c12 = "000";
	private String c13 = "000";
	private String c14 = "000";
	private String c15 = "000";
	private String c16 = "000";
	private String c17 = "000";
	private String c18 = "000";
	private String c19 = "000";
	private String c20 = "000";
	private String c21 = "000";
	
	
	public Test()
	{
		
	}
	
	
	
	public Test(int a ,String b) {
		// TODO Auto-generated constructor stub
		aaa = a;
		bbb = b;
		//System.out.println("construct 2 function is called!!!");
	}
	

	public int getA() {
		return aaa;
	}


	public void setA(int a)
	{
		this.aaa = a;
	}
	
	public String getB() {
		return bbb;
	}

	public void setB(String b) {
		this.bbb = b;
	}
	


	public String getC1() {
		return c1;
	}

	public void setC1(String c1) {
		this.c1 = c1;
	}

	public String getC2() {
		return c2;
	}

	public void setC2(String c2) {
		this.c2 = c2;
	}

	public String getC3() {
		return c3;
	}

	public void setC3(String c3) {
		this.c3 = c3;
	}

	public String getC4() {
		return c4;
	}

	public void setC4(String c4) {
		this.c4 = c4;
	}

	public String getC5() {
		return c5;
	}

	public void setC5(String c5) {
		this.c5 = c5;
	}

	public String getC6() {
		return c6;
	}

	public void setC6(String c6) {
		this.c6 = c6;
	}

	public String getC7() {
		return c7;
	}

	public void setC7(String c7) {
		this.c7 = c7;
	}

	public String getC8() {
		return c8;
	}

	public void setC8(String c8) {
		this.c8 = c8;
	}

	public String getC9() {
		return c9;
	}

	public void setC9(String c9) {
		this.c9 = c9;
	}

	public String getC10() {
		return c10;
	}

	public void setC10(String c10) {
		this.c10 = c10;
	}

	public String getC11() {
		return c11;
	}

	public void setC11(String c11) {
		this.c11 = c11;
	}

	public String getC12() {
		return c12;
	}

	public void setC12(String c12) {
		this.c12 = c12;
	}

	public String getC13() {
		return c13;
	}

	public void setC13(String c13) {
		this.c13 = c13;
	}

	public String getC14() {
		return c14;
	}

	public void setC14(String c14) {
		this.c14 = c14;
	}

	public String getC15() {
		return c15;
	}

	public void setC15(String c15) {
		this.c15 = c15;
	}

	public String getC16() {
		return c16;
	}

	public void setC16(String c16) {
		this.c16 = c16;
	}

	public String getC17() {
		return c17;
	}

	public void setC17(String c17) {
		this.c17 = c17;
	}

	public String getC18() {
		return c18;
	}

	public void setC18(String c18) {
		this.c18 = c18;
	}

	public String getC19() {
		return c19;
	}

	public void setC19(String c19) {
		this.c19 = c19;
	}

	public String getC20() {
		return c20;
	}

	public void setC20(String c20) {
		this.c20 = c20;
	}

	public String getC21() {
		return c21;
	}

	public void setC21(String c21) {
		this.c21 = c21;
	}
	
	
	//test
	 /**
	 * @param args
	 * @throws Exception
	 */
	public static void main(String[] args) throws Exception  
	 {     	 
		 
		  
		   Test test =new Test(2,"222");
		   
		   
		   //JackJSON 初始化
		   ObjectMapper objectMapper = new ObjectMapper();  
		 
		   long startTime=0;   //获取开始时间
		   long endTime=0; //获取结束时间
		   
		   int  loopCount  =100000;
		   
//         code + decode -----------------------------------------------------
//         10000  - 23 members
//		   Jackson :235750737 ns
//		   FastJSON:347795550 ns
//         10000  - 2 members
//		   Jackson :164173126 ns
//		   FastJSON:159078284 ns
		   
		   
//	       100000 - 23 members
//		   Jackson :1004902734 ns
//		   FastJSON:1689072614 ns
//	       100000 - 2 members 
//		   Jackson :392344461 ns
//		   FastJSON:299521240 ns
		   
// 	       1000000 - 23 members
//		   Jackson :8547741285 ns
//		   FastJSON:15377369425 ns
// 	       1000000 - 2 members
//		   Jackson :2581267623 ns
//		   FastJSON:1591827729 ns
		   
//         code only -------------------------------------------------------
//         10000  - 23 members
//		   Jackson :115036100 ns
//		   FastJSON:158681243 ns
//         10000  - 2 members
//		   Jackson :87886170 ns
//		   FastJSON:103086025 ns
		   
		   
//	       100000 - 23 members
//		   Jackson :417539325 ns
//		   FastJSON:349358062 ns
//	       100000 - 2 members 
//		   Jackson :185865488 ns
//		   FastJSON:144893485 ns
		   
// 	       1000000 - 23 members
//		   Jackson :3384171740 ns
//		   FastJSON:2200190119 ns
// 	       1000000 - 2 members
//		   Jackson :1193815955 ns
//		   FastJSON:568776506 ns
		   
		   
//         decode only -------------------------------------------------------
//         10000  - 23 members
//		   Jackson :122597862 ns
//		   FastJSON:183567261 ns
//         10000  - 2 members
//		   Jackson :75418145 ns
//		   FastJSON:47832689 ns
		   
		   
//	       100000 - 23 members
//		   Jackson :497670344 ns
//		   FastJSON:1254994458 ns
//	       100000 - 2 members 
//		   Jackson :165368101 ns
//		   FastJSON:117555618 ns
		   
// 	       1000000 - 23 members
//		   Jackson :4189147981 ns
//		   FastJSON:12004873228 ns
// 	       1000000 - 2 members
//		   Jackson :999578584 ns
//		   FastJSON:863444723 ns
		   
		   //Jackson
		  
		  
		   startTime =  System.nanoTime();
		 
		   for(int i=0;i


还有一篇TS回复挑战者的基准测试结果的文章,虽然和本文没有直接关系,但是反映了一些东西。可以了解了解。

http://www.infoq.com/cn/news/2014/05/jackson-founder-responds



你可能感兴趣的:(Java)