blocks|key|3054614|text|我们在我们的项目中使用了http://json-lib.sourceforge.net/，它工作得很好。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3054615|entityMap|0|LINK|mutability|MUTABLE|url|http://json-lib.sourceforge.net/^0|C|W|0|0^^$0|@$1|2|3|4|5|6|7|L|8|@]|9|@$A|M|B|N|1|O]]|C|$]]|$1|D|3|-4|5|6|7|P|8|@]|9|@]|C|$]]]|E|$F|$5|G|H|I|C|$J|K]]]]

We use <a href="http://json-lib.sourceforge.net/" rel="nofollow noreferrer">http://json-lib.sourceforge.net/</a> in our project, it works just fine.

blocks|key|3054628|text|JSON-Simple看起来相对容易使用(下面的例子)。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3054629|映射到JSON：|3054630|++Map+map+=+new+HashMap();
++map.put("name",+"foo");
++map.put("nickname",+"bar");
++String+jsonText+=+JSONValue.toJSONString(map);|code-block|syntax|javascript|3054631|JSON+to+List/Map：|3054632|++String+s+=+yourJsonString;
++List+list+=+(JSONArray)+JSONValue.parse(s);+++++++
++Map+map+=+(JSONObject)+list.get(0);|3054633|entityMap|0|LINK|mutability|MUTABLE|url|http://code.google.com/p/json-simple/^0|0|B|0|0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]]|C|$]]|$1|D|3|E|5|6|7|10|8|@]|9|@]|C|$]]|$1|F|3|G|5|H|7|11|8|@]|9|@]|C|$I|J]]|$1|K|3|L|5|6|7|12|8|@]|9|@]|C|$]]|$1|M|3|N|5|H|7|13|8|@]|9|@]|C|$I|J]]|$1|O|3|-4|5|6|7|14|8|@]|9|@]|C|$]]]|P|$Q|$5|R|S|T|C|$U|V]]]]

<a href="http://code.google.com/p/json-simple/" rel="noreferrer">JSON-Simple</a> looks relatively easy to use (examples below).

Map to JSON:

<pre><code> Map map = new HashMap();
 map.put("name", "foo");
 map.put("nickname", "bar");
 String jsonText = JSONValue.toJSONString(map);
</code></pre>

JSON to List/Map:

<pre><code> String s = yourJsonString;
 List list = (JSONArray) JSONValue.parse(s); 
 Map map = (JSONObject) list.get(0);
</code></pre>

blocks|key|3054639|text|为此，您可以使用Google+Gson。它对Generic+types有很好的支持。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|3054640|这是一个SSCCE|3054641|package+com.stackoverflow.q2496494;

import+java.util.LinkedHashMap;
import+java.util.Map;

import+com.google.gson.Gson;
import+com.google.gson.reflect.TypeToken;

public+class+Test+{

+++public+static+void+main(String...+args)+{
++++++++Map<String,+String>+map+=+new+LinkedHashMap<String,+String>();
++++++++map.put("key1",+"value1");
++++++++map.put("key2",+"value2");
++++++++map.put("key3",+"value3");
++++++++Gson+gson+=+new+Gson();

++++++++//+Serialize.
++++++++String+json+=+gson.toJson(map);
++++++++System.out.println(json);+//+{"key1":"value1","key2":"value2","key3":"value3"}

++++++++//+Deserialize.
++++++++Map<String,+String>+map2+=+gson.fromJson(json,+new+TypeToken<Map<String,+String>>()+{}.getType());
++++++++System.out.println(map2);+//+{key1=value1,+key2=value2,+key3=value3}
++++}

}|code-block|syntax|javascript|3054642|entityMap|0|LINK|mutability|MUTABLE|url|http://code.google.com/p/google-gson/|1|http://sites.google.com/site/gson/gson-user-guide#TOC-Serializing-and-Deserializing-Gener|2|http://sscce.org/^0|8|B|0|M|D|1|0|4|5|2|0|0^^$0|@$1|2|3|4|5|6|7|W|8|@]|9|@$A|X|B|Y|1|Z]|$A|10|B|11|1|12]]|C|$]]|$1|D|3|E|5|6|7|13|8|@]|9|@$A|14|B|15|1|16]]|C|$]]|$1|F|3|G|5|H|7|17|8|@]|9|@]|C|$I|J]]|$1|K|3|-4|5|6|7|18|8|@]|9|@]|C|$]]]|L|$M|$5|N|O|P|C|$Q|R]]|S|$5|N|O|P|C|$Q|T]]|U|$5|N|O|P|C|$Q|V]]]]

You can use <a href="http://code.google.com/p/google-gson/" rel="noreferrer">Google Gson</a> for that. It has excellent support for <a href="http://sites.google.com/site/gson/gson-user-guide#TOC-Serializing-and-Deserializing-Gener" rel="noreferrer">Generic types</a>.

Here's an <a href="http://sscce.org" rel="noreferrer">SSCCE</a>:

<pre><code>package com.stackoverflow.q2496494;

import java.util.LinkedHashMap;
import java.util.Map;

import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;

public class Test {

 public static void main(String... args) {
 Map&lt;String, String&gt; map = new LinkedHashMap&lt;String, String&gt;();
 map.put("key1", "value1");
 map.put("key2", "value2");
 map.put("key3", "value3");
 Gson gson = new Gson();

 // Serialize.
 String json = gson.toJson(map);
 System.out.println(json); // {"key1":"value1","key2":"value2","key3":"value3"}

 // Deserialize.
 Map&lt;String, String&gt; map2 = gson.fromJson(json, new TypeToken&lt;Map&lt;String, String&gt;&gt;() {}.getType());
 System.out.println(map2); // {key1=value1, key2=value2, key3=value3}
 }

}
</code></pre>

blocks|key|313640|text|您可以从Json.org查看该站点，以获取用Java语言编写的优秀JSON库的列表。|type|unstyled|depth|inlineStyleRanges|entityRanges|offset|length|data|313641|own自己的implementation+JSONObject就可以做到这一点。从他们的JavaDoC|style|CODE|313642|+/**
+++++*+Construct+a+JSONObject+from+a+Map.
+++++*+
+++++*+@param+map+A+map+object+that+can+be+used+to+initialize+the+contents+of
+++++*++the+JSONObject.
+++++*/
++++public+JSONObject(Map+map);|code-block|syntax|javascript|313643|你可以做到|313644|JSONObject+json+=+new+JSONObject(map);|313645|要将JSON字符串转换回object...|313646|String+jsonString+=+"{\"name\"+:+\"some+name\",+\"age\"+:+10}";
JSONObject+json+=+new+JSONObject(jsonString);|313647|您可以访问如下值：|313648|int+age+=+json.getInt("age");|313649|构造函数JavaDoC|313650|313651|从源JSON文本字符串构造JSONObject。这是最常用的JSONObject构造函数。|blockquote|313652|313653|参数:+source以{开头的字符串(左括号)，以}结尾的字符串(右括号)。|313654|entityMap|0|LINK|mutability|MUTABLE|url|http://www.json.org/|1|http://www.json.org/java/index.html^0|4|8|0|0|L|A|6|E|1|0|0|0|0|0|0|0|0|0|0|0|0|B|1|P|1|0^^$0|@$1|2|3|4|5|6|7|1H|8|@]|9|@$A|1I|B|1J|1|1K]]|C|$]]|$1|D|3|E|5|6|7|1L|8|@$A|1M|B|1N|F|G]]|9|@$A|1O|B|1P|1|1Q]]|C|$]]|$1|H|3|I|5|J|7|1R|8|@]|9|@]|C|$K|L]]|$1|M|3|N|5|6|7|1S|8|@]|9|@]|C|$]]|$1|O|3|P|5|J|7|1T|8|@]|9|@]|C|$K|L]]|$1|Q|3|R|5|6|7|1U|8|@]|9|@]|C|$]]|$1|S|3|T|5|J|7|1V|8|@]|9|@]|C|$K|L]]|$1|U|3|V|5|6|7|1W|8|@]|9|@]|C|$]]|$1|W|3|X|5|J|7|1X|8|@]|9|@]|C|$K|L]]|$1|Y|3|Z|5|6|7|1Y|8|@]|9|@]|C|$]]|$1|10|3|-4|5|6|7|1Z|8|@]|9|@]|C|$]]|$1|11|3|12|5|13|7|20|8|@]|9|@]|C|$]]|$1|14|3|-4|5|6|7|21|8|@]|9|@]|C|$]]|$1|15|3|16|5|6|7|22|8|@$A|23|B|24|F|G]|$A|25|B|26|F|G]]|9|@]|C|$]]|$1|17|3|-4|5|6|7|27|8|@]|9|@]|C|$]]]|18|$19|$5|1A|1B|1C|C|$1D|1E]]|1F|$5|1A|1B|1C|C|$1D|1G]]]]

You can view the site from <a href="http://www.json.org/" rel="nofollow noreferrer">Json.org</a> for the list of good JSON libraries in Java. 

JSon.org's own <a href="http://www.json.org/java/index.html" rel="nofollow noreferrer">implementation</a> <code>JSONObject</code> can do just that.
From their JavaDoC

<pre><code> /**
 * Construct a JSONObject from a Map.
 * 
 * @param map A map object that can be used to initialize the contents of
 * the JSONObject.
 */
 public JSONObject(Map map);
</code></pre>

you can do 

<pre><code>JSONObject json = new JSONObject(map);
</code></pre>

To convert JSON String back to object....

<pre><code>String jsonString = "{\"name\" : \"some name\", \"age\" : 10}";
JSONObject json = new JSONObject(jsonString);
</code></pre>

and you can access values like:

<pre><code>int age = json.getInt("age");
</code></pre>

Constructor JavaDoC

<blockquote>
 Construct a JSONObject from a source
 JSON text string. This is the most
 commonly used JSONObject constructor.
 
 Parameters: source A string beginning
 with <code>{</code> (left brace) and ending with <code>}</code>
 (right brace).
</blockquote>

blocks|key|3054662|text|我猜真正的问题是哪个JSON库(来自org.json的页面)不允许这样做。据我所知，每个单独的库都会以某种形式允许这样做。因此，到目前为止提到的每个库都可以工作。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|3054663|为了添加一些信息，Jackson可以很好地处理所有类型的数据，包括基本地图和列表：|offset|length|3054664|ObjectMapper+mapper+=+new+ObjectMapper();
String+json+=+mapper.writeValue(list);
List+listOfMaps+=+mapper.readValue(json,+List.class);|code-block|syntax|javascript|3054665|它会处理这种特殊的情况。虽然可以使用泛型类型信息，但在使用JDK容器类型的“自然”绑定时，它是可选的。|3054666|entityMap|0|LINK|mutability|MUTABLE|url|http://jackson.codehaus.org/^0|0|9|7|0|0|0|0^^$0|@$1|2|3|4|5|6|7|U|8|@]|9|@]|A|$]]|$1|B|3|C|5|6|7|V|8|@]|9|@$D|W|E|X|1|Y]]|A|$]]|$1|F|3|G|5|H|7|Z|8|@]|9|@]|A|$I|J]]|$1|K|3|L|5|6|7|10|8|@]|9|@]|A|$]]|$1|M|3|-4|5|6|7|11|8|@]|9|@]|A|$]]]|N|$O|$5|P|Q|R|A|$S|T]]]]

I guess the real question would be which JSON library (from org.json's page) would NOT allow doing this. As far as I know every single library there would allow this in some form.
So every library mentioned so far works.

And to add some information, <a href="http://jackson.codehaus.org" rel="nofollow">Jackson</a> works very well with all kinds of data including basic Maps and Lists:

<pre><code>ObjectMapper mapper = new ObjectMapper();
String json = mapper.writeValue(list);
List listOfMaps = mapper.readValue(json, List.class);
</code></pre>

which would handle this particular case. While generic type information can be used, it is optional when using "natural" binding to JDK container types.

blocks|key|313659|text|在使用google+gson时。|type|unstyled|depth|inlineStyleRanges|entityRanges|data|313660|var+getRowData+=
[{
++++"dayOfWeek":+"Sun",
++++"date":+"11-Mar-2012",
++++"los":+"1",
++++"specialEvent":+"",
++++"lrv":+"0"
},
{
++++"dayOfWeek":+"Mon",
++++"date":+"",
++++"los":+"2",
++++"specialEvent":+"",
++++"lrv":+"0.16"
}];

++++JsonElement+root+=+new+JsonParser().parse(request.getParameter("getRowData"));
+++++JsonArray++jsonArray+=+root.getAsJsonArray();
+++++JsonObject++jsonObject1+=+jsonArray.get(0).getAsJsonObject();
+++++String+dayOfWeek+=+jsonObject1.get("dayOfWeek").toString();|code-block|syntax|javascript|313661|//使用jackson时|313662|++++JsonFactory+f+=+new+JsonFactory();
++++++++++++++ObjectMapper+mapper+=+new+ObjectMapper();
++++++++++JsonParser+jp+=+f.createJsonParser(getRowData);
++++++++++//+advance+stream+to+START_ARRAY+first:
++++++++++jp.nextToken();
++++++++++//+and+then+each+time,+advance+to+opening+START_OBJECT
+++++++++while+(jp.nextToken()+==+JsonToken.START_OBJECT)+{
++++++++++++Map<String,Object>+userData+=+mapper.readValue(jp,+Map.class);
++++++++++++userData.get("dayOfWeek");
++++++++++++//+process
+++++++++++//+after+binding,+stream+points+to+closing+END_OBJECT
++++++++}|313663|entityMap^0|0|0|0|0^^$0|@$1|2|3|4|5|6|7|M|8|@]|9|@]|A|$]]|$1|B|3|C|5|D|7|N|8|@]|9|@]|A|$E|F]]|$1|G|3|H|5|6|7|O|8|@]|9|@]|A|$]]|$1|I|3|J|5|D|7|P|8|@]|9|@]|A|$E|F]]|$1|K|3|-4|5|6|7|Q|8|@]|9|@]|A|$]]]|L|$]]

When using google gson.

<pre><code>var getRowData =
[{
 "dayOfWeek": "Sun",
 "date": "11-Mar-2012",
 "los": "1",
 "specialEvent": "",
 "lrv": "0"
},
{
 "dayOfWeek": "Mon",
 "date": "",
 "los": "2",
 "specialEvent": "",
 "lrv": "0.16"
}];

 JsonElement root = new JsonParser().parse(request.getParameter("getRowData"));
 JsonArray jsonArray = root.getAsJsonArray();
 JsonObject jsonObject1 = jsonArray.get(0).getAsJsonObject();
 String dayOfWeek = jsonObject1.get("dayOfWeek").toString();
</code></pre>

// when using jackson 

<pre><code> JsonFactory f = new JsonFactory();
 ObjectMapper mapper = new ObjectMapper();
 JsonParser jp = f.createJsonParser(getRowData);
 // advance stream to START_ARRAY first:
 jp.nextToken();
 // and then each time, advance to opening START_OBJECT
 while (jp.nextToken() == JsonToken.START_OBJECT) {
 Map&lt;String,Object&gt; userData = mapper.readValue(jp, Map.class);
 userData.get("dayOfWeek");
 // process
 // after binding, stream points to closing END_OBJECT
 }
</code></pre>

Does anyone knows a java library that could easily encode java Maps into json objects and the other way around? 

UPDATE

For reasons couldn't explain ( and I hate sometimes ) I can't use generics on my environment. 

What' I'm trying to do is to have something like this:

<pre><code>Map a = new HashMap();
a.put( "name", "Oscar" );

Map b = new HashMap();
b.put( "name", "MyBoss"); 
a.put( "boss", b ) ;


List list = new ArrayList();
list.add( a );
list.add( b );


 String json = toJson( list );
 // and create the json:
 /*
 [
 {
 "name":"Oscar",
 "boss":{
 "name":"MyBoss"
 }
 },
 {
 "name":"MyBoss"
 }
 ]

 */ 
</code></pre>

And be able to have it again as a list of maps

<pre><code> List aList = ( List ) fromJson( jsonStirng );
</code></pre>

Library to encode/decode from json to java.util.Map?

容器

JSON

Java

有没有人知道一个java库可以很容易地将java Maps编码成json对象，反之亦然？更新由于无法解释(有时我讨厌)的原因，我不能在我的环境中使用泛型。我想要做的是拥有这样的东西：Map a = new HashMap();a.put( "name", "Oscar" );Map b = new HashMap();...

问库将json编码/解码为java.util.Map？
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问库将json编码/解码为java.util.Map？
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