JSON

JSON作为一种信息的载体伴随着AJAX的红火也越来越得到广大用户的青睐和认可！在没有使用JSON的时候，数据 从后台数据库到前台AJAX的返回显示，一般都要经过SQL查询--数据封装(封装成字符串或者XML文本)--前台解析 字符串或者XML文本，提取需要的东西出来。这其中包含了太多的转换关系，劳明伤财，也有很多人在探索一种 能够使大家都能认识的数据结构，这个时候大家都想到了JSON,可以说JSON也不是新的东西，出来好多年了， Javascript一直都内置了JSON的支持，很多时候我们都是使用JSON的语法来定义一个Javascript的对象！看一看 JSON的官方网站(http://json.org/)就知道它目前基本上已经覆盖了大多数语言，这意味着大多数情况下的跨语言 环境下的数据交换，使用JSON是一个不错的选择！ 1. Javascript(虽然已经内置支持，但是这里有一个开发包可以使用) (1) 使用JSON语法定义一个Javascript对象 var myJSONObject = {"bindings": [ {"ircEvent": "PRIVMSG", "method": "newURI", "regex": "^http://.*"}, {"ircEvent": "PRIVMSG", "method": "deleteURI", "regex": "^delete.*"}, {"ircEvent": "PRIVMSG", "method": "randomURI", "regex": "^random.*"} ] }; myJSONObject.bindings[0].method 将返回newURI (2) 把普通字符串转换成JavaScript对象(需要扩展包支持) var myObject = JSON.parse(myJSONtext, filter); myData = JSON.parse(text, function (key, value) { return key.indexOf('date') >= 0 ? new Date(value) : value; }); (3) JSON对象转换成字符串 var myJSONText = JSON.stringify(myObject); 2. Java对JSON的支持(没有原生的支持，需要使用第三方的扩展包来实现) Java的JSON开发包很多，也有很多实用且功能强大的 (1) json-lib (http://json-lib.sourceforge.net/usage.html) a.) JSON和Java的类型对应关系 JSON Java string java.lang.String, java.lang.Character, char number java.lang.Number, byte, short, int, long, float, double true|false java.lang.Boolean, boolean null null function net.sf.json.JSONFunction array net.sf.json.JSONArray (object, string, number, boolean, function) object net.sf.json.JSONObject b.) json-lib的依赖库 jakarta commons-lang 2.3 jakarta commons-beanutils 1.7.0 jakarta commons-collections 3.2 jakarta commons-logging 1.1 ezmorph 1.0.3 xom 1.1(如果要用到xml文件的解析的话) c.) 可运行实例 package com.gomt.json.jsonlib; import java.lang.reflect.InvocationTargetException; import java.util.ArrayList; import java.util.Collection; import java.util.HashMap; import java.util.List; import java.util.Map; import net.sf.json.JSONArray; import net.sf.json.JSONObject; import net.sf.json.xml.XMLSerializer; import org.apache.commons.beanutils.PropertyUtils; public class JsonLibMain { public JsonLibMain() { // TODO Auto-generated constructor stub } /** * @param args * @throws NoSuchMethodException * @throws InvocationTargetException * @throws IllegalAccessException */ public static void main(String[] args) throws IllegalAccessException, InvocationTargetException, NoSuchMethodException { boolean[] boolArray = new boolean[]{true,false,true}; JSONArray jsonArray = JSONArray.fromObject( boolArray ); System.out.println("***1*** = " + jsonArray ); Collection<string> list = new ArrayList<string>(); list.add( "first" ); list.add( "second" ); jsonArray = JSONArray.fromObject( list ); System.out.println("***2*** = " + jsonArray ); jsonArray = JSONArray.fromObject( "['json','is','easy']" ); System.out.println("***3*** = " + jsonArray ); Map<string object> map = new HashMap<string object>(); map.put( "name", "json" ); map.put( "bool", Boolean.TRUE ); map.put( "int", new Integer(1) ); map.put( "arr", new String[]{"a","b"} ); map.put( "func", "function(i){ return this.arr[i]; }" ); JSONObject jsonObject = JSONObject.fromObject( map ); System.out.println("***4*** = " + jsonObject ); jsonObject = JSONObject.fromObject( new MyBean() ); System.out.println("***5*** = " + jsonObject ); String json = "{name=\"json\",bool:true,int:1,double:2.2,func:function(a){ return a; },array:[1,2]}"; jsonObject = JSONObject.fromObject( json ); Object bean = JSONObject.toBean( jsonObject ); System.out.print("***6*** = " + jsonObject.get( "name" ) + " " + PropertyUtils.getProperty( bean, "name" ) ); System.out.print("\t " + jsonObject.get( "bool" ) + " = " + PropertyUtils.getProperty( bean, "bool" ) ); System.out.print("\t " + jsonObject.get( "int" ) + " = " + PropertyUtils.getProperty( bean, "int" ) ); System.out.print("\t " + jsonObject.get( "double" ) + " = " + PropertyUtils.getProperty( bean, "double" ) ); System.out.print("\t " + jsonObject.get( "func" ) + " = " + PropertyUtils.getProperty( bean, "func" ) ); List expected = JSONArray.toList( jsonObject.getJSONArray( "array" ) ); System.out.println("\t " + expected + " = " + (List) PropertyUtils.getProperty( bean, "array" ) ); json = "{bool:true,integer:1,string:\"json\"}"; jsonObject = JSONObject.fromObject( json ); MyBean myBean = (MyBean) JSONObject.toBean( jsonObject, MyBean.class ); System.out.print("***7*** = " + jsonObject.get( "bool" ) + " = " + Boolean.valueOf( myBean.isBool() ) ); System.out.print("\t " + jsonObject.get( "integer" ) + " = " +new Integer( myBean.getInteger() ) ); System.out.println("\t " + jsonObject.get( "string" )+ " = " + myBean.getString() ); //需要用到ezmorph json = "{'data':[{'name':'clarance','userId':100001},{'name':'peng','userId':100002}]}"; Map<string>&gt; classMap = new HashMap<string>&gt;(); classMap.put( "data", Person.class ); myBean = (MyBean)JSONObject.toBean(JSONObject.fromObject(json), MyBean.class, classMap); if(myBean != null &amp;&amp; myBean.getData() != null) { for(Person p : myBean.getData()) { System.out.println("***8*** = " + "用户id: " + p.getUserId() + " 用户名: " + p.getName()); } } /* Morpher dynaMorpher = new BeanMorpher( Person.class, JSONUtils.getMorpherRegistry() ); MorpherRegistry morpherRegistry = new MorpherRegistry(); morpherRegistry.registerMorpher( dynaMorpher ); List output = new ArrayList(); for( Iterator i = myBean.getData().iterator(); i.hasNext(); ){ output.add( morpherRegistry.morph( Person.class, i.next() ) ); } myBean.setData( output ); */ /** * XML和JSON之间的转换,需要用到xom */ jsonObject = new JSONObject( true ); XMLSerializer xmls = new XMLSerializer(); String xml = xmls.write( jsonObject ); System.out.println("***9*** = " + xml); jsonObject = JSONObject.fromObject("{\"name\":\"json\",\"bool\":true,\"int\":1}"); xmls = new XMLSerializer(); xml = xmls.write( jsonObject ); System.out.println("***10*** = " + xml); jsonArray = JSONArray.fromObject("[1,2,3]"); xmls = new XMLSerializer(); xml = xmls.write( jsonArray ); System.out.println("***11*** = " + xml); xml = "<a class='\"array\"'><e type='\"function\"' params='\"i,j\"'>return matrix[i][j];</e></a> "; xmls = new XMLSerializer(); jsonArray = (JSONArray) xmls.read( xml); System.out.println("***12*** = " + jsonArray ); } } package com.gomt.json.jsonlib; import java.util.List; import net.sf.json.JSONFunction; public class MyBean implements java.io.Serializable { private static final long serialVersionUID = -784610042144660631L; private String name = "json"; private int pojoId = 1; private char[] options = new char[]{'a','f'}; private String func1 = "function(i){ return this.options[i]; }"; private JSONFunction func2 = new JSONFunction(new String[]{"i"},"return this.options[i];"); private Integer integer; private Boolean bool; private String string; private List<person> data; public Boolean isBool() { return bool; } public void setBool(Boolean bool) { this.bool = bool; } public String getString() { return string; } public void setString(String string) { this.string = string; } public String getName() { return name; } public void setName(String name) { this.name = name; } public int getPojoId() { return pojoId; } public void setPojoId(int pojoId) { this.pojoId = pojoId; } public char[] getOptions() { return options; } public void setOptions(char[] options) { this.options = options; } public String getFunc1() { return func1; } public void setFunc1(String func1) { this.func1 = func1; } public JSONFunction getFunc2() { return func2; } public void setFunc2(JSONFunction func2) { this.func2 = func2; } public Integer getInteger() { return integer; } public void setInteger(Integer integer) { this.integer = integer; } public Boolean getBool() { return bool; } public List<person> getData() { return data; } public void setData(List<person> data) { this.data = data; } } package com.gomt.json.jsonlib; import java.io.Serializable; public class Person implements Serializable { private static final long serialVersionUID = 7699163849016962711L; private int userId; private String name; public int getUserId() { return userId; } public void setUserId(int userId) { this.userId = userId; } public String getName() { return name; } public void setName(String name) { this.name = name; } } d.) 运行结果 ***1*** = [true,false,true] ***2*** = ["first","second"] ***3*** = ["json","is","easy"] ***4*** = {"func":function(i){ return this.arr[i]; },"arr":["a","b"],"int":1,"name":"json","bool":true} ***5*** = {"string":"","integer":0,"func1":function(i){ return this.options[i]; },"data":[],"pojoId":1,"name":"json","bool":false,"options":["a","f"],"func2":function(i){ return this.options[i]; }} ***6*** = json json true = true 1 = 1 2.2 = 2.2 function(a){ return a; } = function(a){ return a; } [1, 2] = [1, 2] ***7*** = true = true 1 = 1 json = json ***8*** = 用户id: 100001 用户名: clarance ***8*** = 用户id: 100002 用户名: peng ***9*** = <?xml version="1.0" encoding="UTF-8"?><o null="true"></o> ***10*** = <?xml version="1.0" encoding="UTF-8"?><o><bool type="boolean">true</bool><int type="number">1</int><name type="string">json</name></o> ***11*** = <?xml version="1.0" encoding="UTF-8"?><a><e type="number">1</e><e type="number">2</e><e type="number">3</e></a> 2007-12-7 9:08:29 net.sf.json.xml.XMLSerializer getType 信息: Using default type string ***12*** = [function(i,j){ return matrix[i][j]; }] </person></person></person></string></string></string></string></string></string>