Json-lib快速上手

Json-lib快速上手

 

JSON是一种很简洁很重要的数据格式，通常用来交换传输数据，广泛使用于JavaScript技术中，并逐渐在各种流行编程语言中火了起来。

 

在Java中也有一个JSON的库，用来重要作用就是Java对象与JSON、XML数据的相互转换，有着重要的应用。

 

开源的JSON库主页： http://json-lib.sourceforge.net/

本开源项目的文档非常好，一下是我看快速起步文档所写，原快速上手文档有一些错误和问题，这里都处理过了。

 

环境：

JDK5

json-lib-2.3-jdk15

 

测试所依赖的包：

json-lib-2.3-jdk15.jar
commons-collections.jar
commons-lang.jar
commons-logging.jar
commons-beanutils.jar
ezmorph-1.0.6.jar
xom-1.1.jar

 

测试代码：

import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.xml.XMLSerializer;

import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;

/**
* JSON for Java测试代码
*
* @author leizhimin 2009-12-28 13:15:25
*/
public class TestJSON {
         public static void main(String[] args) {
                test1();
                test2();
                test3();
                test4();
                test5();
        }


         /**
         * 数组或集合-->JSON串
         */
         public static void test1() {
                System.out.println( "------------数组或集合-->JSON串----------");
                 boolean[] boolArray = new boolean[]{ true, false, true};
                JSONArray jsonArray1 = JSONArray.fromObject(boolArray);
                System.out.println(jsonArray1);
//[true,false,true]
                List list = new ArrayList();
                list.add( "first");
                list.add( "second");
                JSONArray jsonArray2 = JSONArray.fromObject(list);
                System.out.println(jsonArray2);
//["first","second"]
                JSONArray jsonArray3 = JSONArray.fromObject( "['json','is','easy']");
                System.out.println(jsonArray3);
// ["json","is","easy"]        
        }

         /**
         * Object|Map-->JSON串
         */
         public static void test2() {
                System.out.println( "------------Object|Map-->JSON串----------");
                Map map = new HashMap();
                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 jsonObject1 = JSONObject.fromObject(map);
                System.out.println(jsonObject1);
//{"func":function(i){ return this.arr[i]; },"arr":["a","b"],"int":1,"bool":true,"name":"json"}

                JSONObject jsonObject2 = JSONObject.fromObject( new MyBean());
                System.out.println(jsonObject2);
//{"func1":function(i){ return this.options[i]; },"func2":function(i){ return this.options[i]; },"name":"json","options":["a","f"],"pojoId":1}
        }

         /**
         * JSON串-->Object
         */
         public static void test3() {
                System.out.println( "------------JSON串-->Object----------");
                String json1 = "{name=\"json\",bool:true,int:1,double:2.2,func:function(a){ return a; },array:[1,2]}";
                JSONObject jsonObject1 = JSONObject.fromObject(json1);
                Object bean1 = JSONObject.toBean(jsonObject1);
                System.out.println(bean1);
//net.sf.ezmorph.bean.MorphDynaBean@10dd1f7[
//    {double=2.2, func=function(a){ return a; }, int=1, name=json, bool=true, array=[1, 2]}
//]
                String json2 = "{bool:true,integer:1,string:\"json\"}";
                JSONObject jsonObject2 = JSONObject.fromObject(json2);
                BeanA bean2 = (BeanA) JSONObject.toBean(jsonObject2, BeanA. class);
                System.out.println(bean2);
// BeanA{bool=true, integer=1, string='json'}
        }

         /**
         * JSON串-->XML
         */
         public static void test4() {
                System.out.println( "------------JSON串-->XML----------");
                JSONObject json = new JSONObject( true);
                String xml = new XMLSerializer().write(json);
                System.out.println(xml);

                JSONObject json1 = JSONObject.fromObject( "{\"name\":\"json\",\"bool\":true,\"int\":1}");
                String xml1 = new XMLSerializer().write(json1);
                System.out.println(xml1);

                JSONArray json2 = JSONArray.fromObject( "[1,2,3]");
                String xml2 = new XMLSerializer().write(json2);
                System.out.println(xml2);
        }

         /**
         * XML-->JSON串
         */
         public static void test5() {
                System.out.println( "------------XML-->JSON串----------");
                String xml = "" +
                                 "class=\"array\">\n" +
                                 "    \n" +
                                 "            return matrix[i][j];\n" +
                                 "    \n" +
                                 "";
                JSONArray json = (JSONArray) new XMLSerializer().read(xml);
                System.out.println(json);
        }
}

 

import net.sf.json.JSONFunction;

/**
* 测试Bean
*
* @author leizhimin 2009-12-28 13:55:09
*/
public class MyBean {
         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];");

         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;
        }
}

 

/**
* 测试Bean
*
* @author leizhimin 2009-12-28 14:18:18
*/
public class BeanA {
         //                 String json2 = "{bool:true,integer:1,string:\"json\"}";
         private boolean bool;
         private Integer integer;
         private String string;

         public boolean isBool() {
                 return bool;
        }

         public void setBool( boolean bool) {
                 this.bool = bool;
        }

         public Integer getInteger() {
                 return integer;
        }

         public void setInteger(Integer integer) {
                 this.integer = integer;
        }

         public String getString() {
                 return string;
        }

         public void setString(String string) {
                 this.string = string;
        }

        @Override
         public String toString() {
                 return "BeanA{" +
                                 "bool=" + bool +
                                 ", integer=" + integer +
                                 ", string='" + string + '\'' +
                                '}';
        }
}

 

运行结果：

------------数组或集合-->JSON串----------
[ true, false, true]
[ "first", "second"]
[ "json", "is", "easy"]
------------Object|Map-->JSON串----------
{ "func":function(i){ return this.arr[i]; }, "arr":[ "a", "b"], "int":1, "bool": true, "name": "json"}
{ "func1":function(i){ return this.options[i]; }, "func2":function(i){ return this.options[i]; }, "name": "json", "options":[ "a", "f"], "pojoId":1}
------------JSON串-->Object----------
net.sf.ezmorph.bean.MorphDynaBean@bd0108[
    { double=2.2, func=function(a){ return a; }, int=1, name=json, bool= true, array=[1, 2]}
]
BeanA{bool= true, integer=1, string='json'}
------------JSON串-->XML----------
"1.0" encoding= "UTF-8"?>
null= "true"/>

"1.0" encoding= "UTF-8"?>
"boolean"> true< int type= "number">1int>"string">json

"1.0" encoding= "UTF-8"?>
"number">1"number">2"number">3

------------XML-->JSON串----------
2009-12-28 15:20:39 net.sf.json.xml.XMLSerializer getType
信息: Using default type string
[function(i,j){ return matrix[i][j]; }]

Process finished with exit code 0

 

特别注意：

 

1、所有的Bean都应该定义为public，否则会出现

net.sf.json.JSONException: java.lang.NoSuchMethodException: Property '***' has no getter method

的错误。

 

2、必须引入xom-1.1.jar包，否则抛出

java.lang.NoClassDefFoundError: nu/xom/Serializer

的异常。

 

另外，还有个开源的JSON库，推荐下：

http://code.google.com/p/google-gson/