fastJson

FastJSON是一个很好的java开源json工具类库，相比其他同类的json类库，它的速度的确是fast，最快！但是文档做得不好，在应用前不得不亲测一些功能。

 

实际上其他的json处理工具都和它差不多，api也有几分相似。

 

一、JSON规范

JSON是一个标准规范，用于数据交互，规范的中文文档如下：

http://www.json.org/json-zh.html

 

参看规范，来对比JSON类库处理结果。

 

二、fastjson的一些简要说明

 

1、了解fastjson

 

Fastjson介绍

Fastjson是一个Java语言编写的JSON处理器。
1、遵循 http://json.org标准，为其官方网站收录的参考实现之一。
2、功能qiang打，支持JDK的各种类型，包括基本的JavaBean、Collection、Map、Date、Enum、泛型。
3、无依赖，不需要例外额外的jar，能够直接跑在JDK上。
4、开源，使用Apache License 2.0协议开源。 http://code.alibabatech.com/wiki/display/FastJSON/Home

如果获得Fastjson？
SVN: http://code.alibabatech.com/svn/fastjson/trunk/
WIKI: http://code.alibabatech.com/wiki/display/FastJSON/Home
Issue Tracking: http://code.alibabatech.com/jira/browse/FASTJSON

 

2、主要的使用入口

 

Fastjson API入口类是com.alibaba.fastjson.JSON，常用的序列化操作都可以在JSON类上的静态方法直接完成。

public   static   final  Object parse(String text);   // 把JSON文本parse为JSONObject或者JSONArray 
public   static   final  JSONObject parseObject(String text)；   // 把JSON文本parse成JSONObject    
public   static   final  <T> T parseObject(String text, Class<T> clazz);   // 把JSON文本parse为JavaBean 
public   static   final  JSONArray parseArray(String text);   // 把JSON文本parse成JSONArray 
public   static   final  <T> List<T> parseArray(String text, Class<T> clazz);   //把JSON文本parse成JavaBean集合 
public   static   final  String toJSONString(Object object);   // 将JavaBean序列化为JSON文本 
public   static   final  String toJSONString(Object object,   boolean  prettyFormat);   // 将JavaBean序列化为带格式的JSON文本 
public   static   final  Object toJSON(Object javaObject); 将JavaBean转换为JSONObject或者JSONArray。

 

 

3、有关类库的一些说明

 

SerializeWriter：相当于StringBuffer

JSONArray：相当于List<Object>

JSONObject：相当于Map<String, Object>

 

JSON反序列化没有真正数组，本质类型都是List<Object>

 

4、fastjson还有很多很高级的特性，比如支持注解、支持全类型序列化，这些都是很好的特性，功能强大，不在本次测试范围。

 

三、测试代码

 

package  lavasoft.stu.json;  

import  com.alibaba.fastjson.JSON;  
import  com.alibaba.fastjson.serializer.SerializeConfig;  
import  com.alibaba.fastjson.serializer.SimpleDateFormatSerializer;  

import  java.util.*;  

/** 
* Created by IntelliJ IDEA. 
* 
* @author leizhimin 11-11-22 上午9:15 
*/  
public   class  Foo {  
         private  String vString =   "vStringhehhehe";  
         private   char  vchar = 'x';  

         private   byte  vbyte = 64;  
         private   short  vshort = 128;  
         private   int  vint = 65535;  
         private   long  vlong = 9999999L;  

         private   float  vfloat = 12.1f;  
         private   double  vdouble = 22.203d;  

         private   boolean  vboolean =   false;  

//        private Date vdate = new Date(); 
         private  Date dddd =   new  Date();  
         private  Date vDate =   new  Date();  
         private  Date v_Date =   new  Date();  
         private  Object vnull =   null;  

         private  String[] avString = { "aaa",   "bbb",   "ccc"};  
         private   int[] avint = {1, 2, 3, 4};  
         private   boolean[] avboolean = { true,   false,   true,   true};  

         private  List<String> listString =   new  ArrayList<String>();  
         private  Map<String, String> map =   new  HashMap<String, String>();  

         private  Bar bar =   new  Bar();  
         private  Bar[] avBar = { new  Bar(),   new  Bar()};  
         private  List<Bar> listBar =   new  ArrayList<Bar>();  

        {  
                listString.add( "listString1");  
                listString.add( "listString2");  
                listString.add( "listString3");  

                map.put( "x",   "s11111x");  
                map.put( "y",   "s22222y");  
                map.put( "z",   "s33333z");  

                listBar.add( new  Bar());  
                listBar.add( new  Bar());  
                listBar.add( new  Bar());  
        }  



         public  String getvString() {  
                 return  vString;  
        }  

         public   void  setvString(String vString) {  
                 this.vString = vString;  
        }  

         public   char  getVchar() {  
                 return  vchar;  
        }  

         public   void  setVchar( char  vchar) {  
                 this.vchar = vchar;  
        }  

         public   byte  getVbyte() {  
                 return  vbyte;  
        }  

         public   void  setVbyte( byte  vbyte) {  
                 this.vbyte = vbyte;  
        }  

         public   short  getVshort() {  
                 return  vshort;  
        }  

         public   void  setVshort( short  vshort) {  
                 this.vshort = vshort;  
        }  

         public   int  getVint() {  
                 return  vint;  
        }  

         public   void  setVint( int  vint) {  
                 this.vint = vint;  
        }  

         public   long  getVlong() {  
                 return  vlong;  
        }  

         public   void  setVlong( long  vlong) {  
                 this.vlong = vlong;  
        }  

         public   float  getVfloat() {  
                 return  vfloat;  
        }  

         public   void  setVfloat( float  vfloat) {  
                 this.vfloat = vfloat;  
        }  

         public   double  getVdouble() {  
                 return  vdouble;  
        }  

         public   void  setVdouble( double  vdouble) {  
                 this.vdouble = vdouble;  
        }  

         public   boolean  isVboolean() {  
                 return  vboolean;  
        }  

         public   void  setVboolean( boolean  vboolean) {  
                 this.vboolean = vboolean;  
        }  

         public  Date getDddd() {  
                 return  dddd;  
        }  

         public   void  setDddd(Date dddd) {  
                 this.dddd = dddd;  
        }  

         public  Date getV_Date() {  
                 return  v_Date;  
        }  

         public   void  setV_Date(Date v_Date) {  
                 this.v_Date = v_Date;  
        }  

         public  Date getvDate() {  
                 return  vDate;  
        }  

         public   void  setvDate(Date vDate) {  
                 this.vDate = vDate;  
        }  

         public  Object getVnull() {  
                 return  vnull;  
        }  

         public   void  setVnull(Object vnull) {  
                 this.vnull = vnull;  
        }  

         public  String[] getAvString() {  
                 return  avString;  
        }  

         public   void  setAvString(String[] avString) {  
                 this.avString = avString;  
        }  

         public   int[] getAvint() {  
                 return  avint;  
        }  

         public   void  setAvint( int[] avint) {  
                 this.avint = avint;  
        }  

         public   boolean[] getAvboolean() {  
                 return  avboolean;  
        }  

         public   void  setAvboolean( boolean[] avboolean) {  
                 this.avboolean = avboolean;  
        }  

         public  List<String> getListString() {  
                 return  listString;  
        }  

         public   void  setListString(List<String> listString) {  
                 this.listString = listString;  
        }  

         public  Map<String, String> getMap() {  
                 return  map;  
        }  

         public   void  setMap(Map<String, String> map) {  
                 this.map = map;  
        }  

         public  Bar getBar() {  
                 return  bar;  
        }  

         public   void  setBar(Bar bar) {  
                 this.bar = bar;  
        }  

         public  Bar[] getAvBar() {  
                 return  avBar;  
        }  

         public   void  setAvBar(Bar[] avBar) {  
                 this.avBar = avBar;  
        }  

         public  List<Bar> getListBar() {  
                 return  listBar;  
        }  

         public   void  setListBar(List<Bar> listBar) {  
                 this.listBar = listBar;  
        }  
}

 

package  lavasoft.stu.json;  

import  com.alibaba.fastjson.JSON;  
import  com.alibaba.fastjson.serializer.SerializeConfig;  
import  com.alibaba.fastjson.serializer.SimpleDateFormatSerializer;  

import  java.util.Date;  
import  java.util.Random;  

/** 
* Created by IntelliJ IDEA. 
* 
* @author leizhimin 11-11-22 上午9:15 
*/  
public   class  Bar {  
         public   static  SerializeConfig mapping =   new  SerializeConfig();  
         private  String barName;  
         private   int  barAge;  
         private  Date barDate =   new  Date();  
         static  {  
                mapping.put(Date. class,   new  SimpleDateFormatSerializer( "yyyy-MM-dd"));  
        }  
        {  
                Random r =   new  Random();  
                barName =   "sss_"+String.valueOf(r.nextFloat());  
                barAge = r.nextInt();  
        }  

         public   static   void  main(String[] args) {  
                Object obj = JSON.toJSON( new  Bar());  
                String x1 = JSON.toJSONString( new  Bar(),   true);  
                System.out.println(x1);  
                String x2 = JSON.toJSONString( new  Bar(), mapping);  
                System.out.println(x2);  
        }  

         public  String getBarName() {  
                 return  barName;  
        }  

         public   void  setBarName(String barName) {  
                 this.barName = barName;  
        }  

         public   int  getBarAge() {  
                 return  barAge;  
        }  

         public   void  setBarAge( int  barAge) {  
                 this.barAge = barAge;  
        }  

         public  Date getBarDate() {  
                 return  barDate;  
        }  

         public   void  setBarDate(Date barDate) {  
                 this.barDate = barDate;  
        }  

        @Override  
         public  String toString() {  
                 return   "Bar{"  +  
                                 "barName='"  + barName + '\'' +  
                                 ", barAge="  + barAge +  
                                 ", barDate="  + barDate +  
                                '}';  
        }  
}

 

 

package  lavasoft.stu.json;  

import  com.alibaba.fastjson.JSON;  
import  com.alibaba.fastjson.JSONArray;  
import  com.alibaba.fastjson.serializer.SerializeConfig;  
import  com.alibaba.fastjson.serializer.SimpleDateFormatSerializer;  

import  java.util.*;  

/** 
* Created by 2IntelliJ IDEA. 
* 
* @author leizhimin 11-11-22 上午9:45 
*/  
public   class  Test {  
         private   static  SerializeConfig mapping =   new  SerializeConfig();   static  {  
                mapping.put(Date. class,   new  SimpleDateFormatSerializer( "yyyy-MM-dd HH:mm:ss"));  
        }  

         public   static   void  main(String[] args) {  
                Foo f1 =   new  Foo();  
                Date date =   new  Date();  
                String text = JSON.toJSONString(date, mapping);  
                System.out.println(text);  
                System.out.println(JSON.toJSONString(f1,   true));  
                String x2 =JSON.toJSONString(f1, mapping);  
                System.out.println(x2);  
        }  

         public   static   void  json2List(){  
                 //List -> JSON array 
                List<Bar> barList =   new  ArrayList<Bar>();  
                barList.add( new  Bar());  
                barList.add( new  Bar());  
                barList.add( new  Bar());  
                String json= JSON.toJSONString(barList,   true);  
                System.out.println(json);  
                 //JSON array -> List 
                List<Bar> barList1 = JSON.parseArray(json,Bar. class);  
                 for  (Bar bar : barList1) {  
                        System.out.println(bar.toString());  
                }  
        }  

         public   static   void  json2Map(){  
                 //Map -> JSON 
                Map<String,Bar> map =   new  HashMap<String, Bar>();  
                map.put( "a", new  Bar());  
                map.put( "b", new  Bar());  
                map.put( "c", new  Bar());  
                String json = JSON.toJSONString(map, true);  
                System.out.println(json);  
                 //JSON -> Map 
                Map<String,Bar> map1 = (Map<String,Bar>)JSON.parse(json);  
                 for  (String key : map1.keySet()) {  
                        System.out.println(key+ ":"+map1.get(key));  
                }  
        }  

         public   static   void  array2JSON(){  
                String[] arr_String    = { "a", "b", "c"};  
                String json_arr_String = JSON.toJSONString(arr_String, true);  
                System.out.println(json_arr_String);  
                JSONArray jsonArray = JSON.parseArray(json_arr_String);  
                 for  (Object o : jsonArray) {  
                        System.out.println(o);  
                }  
                System.out.println(jsonArray);  
        }  
         public   static   void  array2JSON2(){  
                Bar[] arr_Bar    = { new  Bar(), new  Bar(), new  Bar()};  
                String json_arr_Bar = JSON.toJSONString(arr_Bar, true);  
                System.out.println(json_arr_Bar);  
                JSONArray jsonArray = JSON.parseArray(json_arr_Bar);  
                 for  (Object o : jsonArray) {  
                        System.out.println(o);  
                }  
                System.out.println(jsonArray);  
        }  

         public   static   void  map2JSON(){  
                Map map =   new  HashMap();  
                map.put( "a", "aaa");  
                map.put( "b", "bbb");  
                map.put( "c", "ccc");  
                String json=JSON.toJSONString(map);  
                System.out.println(json);  
                Map map1 = JSON.parseObject(json);  
                 for  (Object o : map.entrySet()) {  
                        Map.Entry<String,String> entry = (Map.Entry<String,String>)o;  
                        System.out.println(entry.getKey()+ "--->"+entry.getValue());  
                }  
        }  
}

 

 

说明：

SerializeConfig：是对序列化过程中一些序列化过程的特殊配置，这里用作日期格式的定义。

有关需要带类型的全类型序列化过程，需要调用JSON.toJSONStringZ()方法。

需要美化输出时候，需要打开序列化美化开关，在方法中true那个参数。

 

 

输出结果：

"2011-11-23 23:30:33"  
{  
  "avBar":[{  
    "barAge":174398800,  
    "barDate":1322062233062,  
    "barName":"sss_0.62378174"  
  },{  
    "barAge":38938962,  
    "barDate":1322062233062,  
    "barName":"sss_0.36014742"  
  }],  
  "avString":["aaa","bbb","ccc"],  
  "avboolean":[true,false,true,true],  
  "avint":[1,2,3,4],  
  "bar":{  
    "barAge":1601495948,  
    "barDate":1322062233062,  
    "barName":"sss_0.46644872"  
  },  
  "dddd":1322062233046,  
  "listBar":[  
    {  
      "barAge":-1090113522,  
      "barDate":1322062233062,  
      "barName":"sss_0.83562374"  
    },  
    {  
      "barAge":478603194,  
      "barDate":1322062233062,  
      "barName":"sss_0.59483266"  
    },  
    {  
      "barAge":1118357669,  
      "barDate":1322062233062,  
      "barName":"sss_0.9961642"  
    }  
  ],  
  "listString":[  
    "listString1",  
    "listString2",  
    "listString3"  
  ],  
  "map":{"x":"s11111x","y":"s22222y","z":"s33333z"},  
  "v_Date":1322062233046,  
  "vboolean":false,  
  "vbyte":64,  
  "vchar":"x",  
  "vdouble":22.203,  
  "vfloat":12.1,  
  "vint":65535,  
  "vlong":9999999,  
  "vshort":128  
}  
{"avBar":[{"barAge":174398800,"barDate":"2011-11-23 23:30:33","barName":"sss_0.62378174"},{"barAge":38938962,"barDate":"2011-11-23 23:30:33","barName":"sss_0.36014742"}],"avString":["aaa","bbb","ccc"],"avboolean":[true,false,true,true],"avint":[1,2,3,4],"bar":{"barAge":1601495948,"barDate":"2011-11-23 23:30:33","barName":"sss_0.46644872"},"dddd":"2011-11-23 23:30:33","listBar":[{"barAge":-1090113522,"barDate":"2011-11-23 23:30:33","barName":"sss_0.83562374"},{"barAge":478603194,"barDate":"2011-11-23 23:30:33","barName":"sss_0.59483266"},{"barAge":1118357669,"barDate":"2011-11-23 23:30:33","barName":"sss_0.9961642"}],"listString":["listString1","listString2","listString3"],"map":{"x":"s11111x","y":"s22222y","z":"s33333z"},"v_Date":"2011-11-23 23:30:33","vboolean":false,"vbyte":64,"vchar":"x","vdouble":22.203,"vfloat":12.1,"vint":65535,"vlong":9999999,"vshort":128}  

Process finished with exit code 0  

 

 

fastjson通过各方面测试都很好，功能性能都是No.1，喜欢，它的源代码质量很高，作者也煞费苦心，将性能做到了最好，全免超越其他的json类库。

从其中的源代码中，可以学到很多东西，在阅读源码后，不得不佩服作者高超的程序设计水平，和高质量的编码。