Map与JSON之间转换

//Map转换成JSON

Map<String,String> map = new HashMap<String,String>();
map.put("a","aaa");
map.put("b","bbb");
map.put("c","ccc");
String json=JSON.toJSONString(map);
System.out.println(json);//输出{"a":"aaa","b":"bbb","c":"ccc"}

//JSON转换成Map

Map map1 = JSON.parseObject(json);
System.out.println(map1.get("a"));
for (Object mapData : map.entrySet()) {
Map.Entry<String,String> entry = (Map.Entry<String,String>)mapData;
System.out.println(entry.getKey()+"--->"+entry.getValue());
}
/*输出
b--->bbb
c--->ccc
a--->aaa
*/

map中含有对象Map -> JSON

//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);
/*
输出{
"a":{
"barAge":383687382,
"barDate":1494945882018,
"barName":"name_1689176802"
},
"b":{
"barAge":-100528778,
"barDate":1494945882018,
"barName":"name_-878176366"
},
"c":{
"barAge":-344075192,
"barDate":1494945882018,
"barName":"name_-1710740534"
}
}
*/

//JSON -> Map

Map<String,Bar> map1 = (Map<String,Bar>)JSON.parse(json);
for (String key : map1.keySet()) {
System.out.println(key+":"+map1.get(key));
}
/*输出
b:{"barAge":-100528778,"barDate":1494945882018,"barName":"name_-878176366"}
c:{"barAge":-344075192,"barDate":1494945882018,"barName":"name_-1710740534"}
a:{"barAge":383687382,"barDate":1494945882018,"barName":"name_1689176802"}
*/

来自：http://www.cnblogs.com/DreamDrive/p/5778959.html