json除了可以用于前臺傳遞，還可用于后臺之間傳遞。它可以傳遞List,Map,Bean等類型的數(shù)據(jù)。
例如： User u1=new User();
u1.setUsername("zy");
u1.setPassword("123");
User u2=new User();
u2.setUsername("msl");
u2.setPassword("456");
List list = new ArrayList(); //把兩個對象放進(jìn)list中
list.add(u1);
list.add(u2);
JSONArray jsonArray = JSONArray.fromObject( list ); //把list放進(jìn)json數(shù)組
Map map = new HashMap();
map.put("message", "111");
map.put("users", jsonArray); //把json數(shù)組做為一個值放進(jìn)Map中
JSONObject jsonObject = JSONObject.fromObject(map); //把map放進(jìn)json對象中
PrintWriter out = response.getWriter();
out.print(jsonObject); // 傳遞json
傳遞的json格式為： {"message":"111","users":[{"password":"123","username":"zy"},{"password":"456","username":"msl"}]}
在接收端的java文件中取：
returnJson是從輸入流中得到的json格式的字符串。輸出為：
{"message":"111","users":[{"password":"123","username":"zy"}, {"password":"456","username":"msl"}]}
if(returnJson != null && returnJson != ""){
String strJson = returnJson.replace("?(", "").replace(")", "").replace(";", "");
if(strJson.startsWith("{")){
JSONObject jsonObject = JSONObject.fromObject(strJson);
JSONArray jsonArray = JSONArray.fromObject(jsonObject.get("users"));
for (int i = 0, len = jsonArray.size(); i < len; i++) {
JSONObject jsonUser = jsonArray.getJSONObject(i);
User vo = (User)JSONObject.toBean(jsonUser, User.class);
System.out.println(vo.getUsername()+":"+vo.getPassword());
}
}
}