首先,從 code.google.com/p/google-gson/downloads/list下載GsonAPI:
google-gson-1.7.1-release.zip
把gson-1.7.jar copy到libs(項目根目錄新建一個libs文件夾)中。
可以使用以下兩種方法解析JSON數據:
通過獲取JsonReader對象解析JSON數據:
String jsonData = "[{\"username\":\"arthinking\",\"userId\":001},{\"username\":\"Jason\",\"userId\":002}]"; try{ JsonReader reader = new JsonReader(new StringReader(jsonData)); reader.beginArray(); while(reader.hasNext()){ reader.beginObject(); while(reader.hasNext()){ String tagName = reader.nextName(); if(tagName.equals("username")){ System.out.println(reader.nextString()); } else if(tagName.equals("userId")){ System.out.println(reader.nextString()); } } reader.endObject(); } reader.endArray(); } catch(Exception e){ e.printStackTrace(); }
通過把JSON數據映射成一個對象,使用Gson對象的fromJson()方法獲取一個對象數組進行操作:
創建JSON數據對應的一個POJO對象User.java:
public class User { private String username ; private int userId ; public String getUsername() { return username; } public void setUsername(String username) { this.username = username; } public int getUserId() { return userId; } public void setUserId(int userId) { this.userId = userId; } }
使用Gson對象獲取User對象數據進行相應的操作:
Type listType = new TypeToken<LinkedList<User>>(){}.getType(); Gson gson = new Gson(); LinkedList<User> users = gson.fromJson(jsonData, listType); for (Iterator iterator = users.iterator(); iterator.hasNext();) { User user = (User) iterator.next(); System.out.println(user.getUsername()); System.out.println(user.getUserId()); }
如果要處理的JSON字符串只包含一個JSON對象,則可以直接使用fromJson獲取一個User對象:
String jsonData = "{\"username\":\"arthinking\",\"userId\":001}"; Gson gson = new Gson(); User user = gson.fromJson(jsonData, User.class); System.out.println(user.getUsername()); System.out.println(user.getUserId());