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:
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
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
2、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>
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,"barName":"sss_0.36014742" }],"avString":["aaa","ccc"],"avboolean":[true,true],"avint":[1,4],"bar":{ "barAge":1601495948,"barName":"sss_0.46644872" },"dddd":1322062233046,"listBar":[ { "barAge":-1090113522,"barName":"sss_0.83562374" },{ "barAge":478603194,"barName":"sss_0.59483266" },{ "barAge":1118357669,"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,"barName":"sss_0.36014742"}],"bar":{"barAge":1601495948,"barName":"sss_0.46644872"},"dddd":"2011-11-23 23:30:33","listBar":[{"barAge":-1090113522,"barName":"sss_0.83562374"},{"barAge":478603194,"barName":"sss_0.59483266"},{"barAge":1118357669,"barName":"sss_0.9961642"}],"listString":["listString1","listString3"],"v_Date":"2011-11-23 23:30:33","vshort":128}
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。