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"}
*/