使用json-lib进行Java和JSON之间的转换

资料

来源：互联网

1. json-lib是一个java类库，提供将Java对象，包括beans, maps, collections, java arrays and XML等转换成JSON，或者反向转换的功能。

2. json-lib 主页 ： http://json-lib.sourceforge.net/

3.执行环境

需要以下类库支持

jakarta commons-lang 2.5
jakarta commons-beanutils 1.8.0
jakarta commons-collections 3.2.1
jakarta commons-logging 1.1.1
ezmorph 1.0.6

4.功能示例

这里通过JUnit-Case例子给出代码示例

复制代码
package com.mai.json;

import static org.junit.Assert.assertEquals;

import java.util.ArrayList;
import java.util.Date;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import net.sf.ezmorph.Morpher;
import net.sf.ezmorph.MorpherRegistry;
import net.sf.ezmorph.bean.BeanMorpher;
import net.sf.json.JSONArray;
import net.sf.json.JSONObject;
import net.sf.json.util.JSONUtils;

import org.apache.commons.beanutils.PropertyUtils;
import org.junit.Test;

public class JsonLibTest {

/*
* 普通类型、List、Collection等都是用JSONArray解析
*
* Map、自定义类型是用JSONObject解析
* 可以将Map理解成一个对象，里面的key/value对可以理解成对象的属性/属性值
* 即{key1:value1,key2,value2......}
*
* 1.JSONObject是一个name:values集合，通过它的get(key)方法取得的是key后对应的value部分(字符串)
* 通过它的getJSONObject(key)可以取到一个JSONObject，--> 转换成map,
* 通过它的getJSONArray(key) 可以取到一个JSONArray ，
*
*
*/

//一般数组转换成JSON
@Test
public void testArrayToJSON(){
boolean[] boolArray = new boolean[]{true,false,true};
JSONArray jsonArray = JSONArray.fromObject( boolArray );
System.out.println( jsonArray );
// prints [true,false,true]
}

//Collection对象转换成JSON
@Test
public void testListToJSON(){
List list = new ArrayList();
list.add( "first" );
list.add( "second" );
JSONArray jsonArray = JSONArray.fromObject( list );
System.out.println( jsonArray );
// prints ["first","second"]
}

//字符串json转换成json， 根据情况是用JSONArray或JSONObject
@Test
public void testJsonStrToJSON(){
JSONArray jsonArray = JSONArray.fromObject( "['json','is','easy']" );
System.out.println( jsonArray );
// prints ["json","is","easy"]
}

//Map转换成json， 是用jsonObject
@Test
public void testMapToJSON(){
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 jsonObject = JSONObject.fromObject( map );
System.out.println( jsonObject );
}

//复合类型bean转成成json
@Test
public void testBeadToJSON(){
MyBean bean = new MyBean();
bean.setId("001");
bean.setName("银行卡");
bean.setDate(new Date());

List cardNum = new ArrayList();
cardNum.add("农行");
cardNum.add("工行");
cardNum.add("建行");
cardNum.add(new Person("test"));

bean.setCardNum(cardNum);

JSONObject jsonObject = JSONObject.fromObject(bean);
System.out.println(jsonObject);

}

//普通类型的json转换成对象
@Test
public void testJSONToObject() throws Exception{
String json = "{name=\"json\",bool:true,int:1,double:2.2,func:function(a){ return a; },array:[1,2]}";
JSONObject jsonObject = JSONObject.fromObject( json );
System.out.println(jsonObject);
Object bean = JSONObject.toBean( jsonObject );
assertEquals( jsonObject.get( "name" ), PropertyUtils.getProperty( bean, "name" ) );
assertEquals( jsonObject.get( "bool" ), PropertyUtils.getProperty( bean, "bool" ) );
assertEquals( jsonObject.get( "int" ), PropertyUtils.getProperty( bean, "int" ) );
assertEquals( jsonObject.get( "double" ), PropertyUtils.getProperty( bean, "double" ) );
assertEquals( jsonObject.get( "func" ), PropertyUtils.getProperty( bean, "func" ) );
System.out.println(PropertyUtils.getProperty(bean, "name"));
System.out.println(PropertyUtils.getProperty(bean, "bool"));
System.out.println(PropertyUtils.getProperty(bean, "int"));
System.out.println(PropertyUtils.getProperty(bean, "double"));
System.out.println(PropertyUtils.getProperty(bean, "func"));
System.out.println(PropertyUtils.getProperty(bean, "array"));

List arrayList = (List)JSONArray.toCollection(jsonObject.getJSONArray("array"));
for(Object object : arrayList){
System.out.println(object);
}

}

//将json解析成复合类型对象, 包含List
@Test
public void testJSONToBeanHavaList(){
String json = "{list:[{name:'test1'},{name:'test2'}],map:{test1:{name:'test1'},test2:{name:'test2'}}}";
// String json = "{list:[{name:'test1'},{name:'test2'}]}";
Map classMap = new HashMap();
classMap.put("list", Person.class);
MyBeanWithPerson diyBean = (MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json),MyBeanWithPerson.class , classMap);
System.out.println(diyBean);

List list = diyBean.getList();
for(Object o : list){
if(o instanceof Person){
Person p = (Person)o;
System.out.println(p.getName());
}
}
}

//将json解析成复合类型对象, 包含Map
@Test
public void testJSONToBeanHavaMap(){
//把Map看成一个对象
String json = "{list:[{name:'test1'},{name:'test2'}],map:{testOne:{name:'test1'},testTwo:{name:'test2'}}}";
Map classMap = new HashMap();
classMap.put("list", Person.class);
classMap.put("map", Map.class);
//使用暗示，直接将json解析为指定自定义对象，其中List完全解析,Map没有完全解析
MyBeanWithPerson diyBean = (MyBeanWithPerson)JSONObject.toBean(JSONObject.fromObject(json),MyBeanWithPerson.class , classMap);
System.out.println(diyBean);

System.out.println("do the list release");
List list = diyBean.getList();
for(Person o : list){
Person p = (Person)o;
System.out.println(p.getName());
}

System.out.println("do the map release");

//先往注册器中注册变换器，需要用到ezmorph包中的类
MorpherRegistry morpherRegistry = JSONUtils.getMorpherRegistry();
Morpher dynaMorpher = new BeanMorpher( Person.class, morpherRegistry);
morpherRegistry.registerMorpher( dynaMorpher );

Map map = diyBean.getMap();
/*这里的map没进行类型暗示，故按默认的，里面存的为net.sf.ezmorph.bean.MorphDynaBean类型的对象*/
System.out.println(map);
/*输出:
{testOne=net.sf.ezmorph.bean.MorphDynaBean@f73c1[
{name=test1}
], testTwo=net.sf.ezmorph.bean.MorphDynaBean@186c6b2[
{name=test2}
]}
*/
List output = new ArrayList();
for( Iterator i = map.values().iterator(); i.hasNext(); ){
//使用注册器对指定DynaBean进行对象变换
output.add( (Person)morpherRegistry.morph( Person.class, i.next() ) );
}

for(Person p : output){
System.out.println(p.getName());
/*输出:
test1
test2
*/
}

}

}

public class Person {

private String name = null;

public Person() {

}

public Person(String name) {
this.name = name;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

}

-----------

import java.util.List;
import java.util.Map;

public class MyBeanWithPerson {

private List list = null;
private Map map = null;

public List getList() {
return list;
}

public void setList(List list) {
this.list = list;
}

public Map getMap() {
return map;
}

public void setMap(Map map) {
this.map = map;
}

}

-------------------

import java.util.Date;
import java.util.List;

public class MyBean {

private String id = null;
private String name = null;
private Date date = null;
private List cardNum = null;
private String[] cardType = { "身份证", "银行卡", "公车卡" };

public String getId() {
return id;
}

public void setId(String id) {
this.id = id;
}

public String getName() {
return name;
}

public void setName(String name) {
this.name = name;
}

public Date getDate() {
return date;
}

public void setDate(Date date) {
this.date = date;
}

public List getCardNum() {
return cardNum;
}

public void setCardNum(List cardNum) {
this.cardNum = cardNum;
}

public String[] getCardType() {
return cardType;
}

public void setCardType(String[] cardType) {
this.cardType = cardType;
}

}

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