一個帖子解決伺服器與客戶端傳遞物件的問題，JSON解析兩種方法
阿新 • • 發佈：2019-01-10
只要你對JSON有一點了解，以下內容就非常容易理解，閒話少說，直接上程式碼
**方法一**JSONObject 方法解析物件進行傳遞
先寫伺服器端的程式碼，先寫一個person物件
public class Person {
private int id;
private String name;
private String address;
public Person() {
// TODO Auto-generated constructor stub
}
public int getId() {
return 初始化一下person物件
public class JsonService {
//一個person物件
public Person getPerson(){
Person person=new Person(1001,"hang","suqian");
return person;
}
} 伺服器端json的工具類
public class JsonToos {
public static String CreateJsonString(String key,Object value){
//生成json的string
JSONObject jsonObject=new JSONObject();
jsonObject.put(key,value);
return jsonObject.toString();
}
} 服務端的servlet
public class JsonAction extends HttpServlet {
/**
*
*/
private static final long serialVersionUID = 1L;
private JsonService service;
/**
* @see HttpServlet#HttpServlet()
*/
public JsonAction() {
super();
// TODO Auto-generated constructor stub
}
protected void doGet(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
doPost(request, response);
}
protected void doPost(HttpServletRequest request, HttpServletResponse response) throws ServletException, IOException {
response.setContentType("text/html;charset=utf-8");
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
PrintWriter out=response.getWriter();
String jsonString=JsonToos.CreateJsonString("person",service.getPerson());
out.println(jsonString);
out.flush();
out.close();
}
@Override
public void init() throws ServletException {
service=new JsonService();
}
} 下面為android端的程式碼
注意
這個一定要加的，網路訪問許可權
定義person的物件同上
下面是http的工具類，主要是http訪問，獲取json的字串
public class HttpUtils {
public static String getJsonContent(String path){
try {
URL url=new URL(path);
HttpURLConnection connection=(HttpURLConnection) url.openConnection();
connection.setConnectTimeout(3000);
connection.setRequestMethod("GET");
connection.setDoInput(true);
int code=connection.getResponseCode();
if(code==200){
return changeInputString(connection.getInputStream());
}
} catch (Exception e) {
// TODO: handle exception
}
return "";
}
private static String changeInputString(InputStream inputStream) {
String jsonString="";
ByteArrayOutputStream outPutStream=new ByteArrayOutputStream();
byte[] data=new byte[1024];
int len=0;
try {
while((len=inputStream.read(data))!=-1){
outPutStream.write(data, 0, len);
}
jsonString=new String(outPutStream.toByteArray());
} catch (Exception e) {
// TODO Auto-generated catch block
e.printStackTrace();
}
return jsonString;
}
} 下面為解析json字串，把值賦給person物件
public class JsonTools {
public static Person getPerson(String key, String jsonString) {
Person person = new Person();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONObject personObject = jsonObject.getJSONObject(key);
person.setId(personObject.getInt("id"));
person.setName(personObject.getString("name"));
person.setAddress(personObject.getString("address"));
} catch (Exception e) {
// TODO: handle exception
}
return person;
}
public static List<Person> getPersons(String key, String jsonString) {
List<Person> list = new ArrayList<Person>();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONArray jsonArray = jsonObject.getJSONArray(key);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject2 = jsonArray.getJSONObject(i);
Person person = new Person();
person.setId(jsonObject2.getInt("id"));
person.setName(jsonObject2.getString("name"));
person.setAddress(jsonObject2.getString("address"));
list.add(person);
}
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
public static List<String> getlistString(String key, String jsonString) {
List<String> list = new ArrayList<String>();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONArray jsonArray = jsonObject.getJSONArray(key);
for (int i = 0; i < jsonArray.length(); i++) {
String msg = jsonArray.getString(i);
list.add(msg);
}
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
public static List<Map<String,Object>> getlistMap(String key, String jsonString){
List<Map<String,Object>> list=new ArrayList<Map<String,Object>>();
try {
JSONObject jsonObject = new JSONObject(jsonString);
JSONArray jsonArray = jsonObject.getJSONArray(key);
for (int i = 0; i < jsonArray.length(); i++) {
JSONObject jsonObject2 = jsonArray.getJSONObject(i);
Map<String,Object> map=new HashMap<String, Object>();
Iterator<String> iterator=jsonObject2.keys();
while(iterator.hasNext()){
String json_key=iterator.next();
Object json_value=jsonObject2.get(json_key);
if(json_value==null){
json_value="";
}
map.put(json_key, json_value);
}
list.add(map);
}
}catch(Exception e){
e.printStackTrace();
}
return list;
}
} android點選button觸發的事件
@Override
public void onClick(View v) {
switch (v.getId()) {
case R.id.person:
path="http://192.168.123.1/http/JsonAction";
String jsonstring=HttpUtils.getJsonContent(path);
Log.i(TAG,"1212"+jsonstring);
Person person=JsonTools.getPerson("person", jsonstring);
Log.i(TAG,person.toString());
break;
default:
break;
}
}
} 完成了json的解析！！！
**方法二**Gson方法解析物件進行傳遞
Gson解析是我最喜歡的，感覺特別方便
伺服器端
通過一個Person物件返回一個Person物件的JSON字串
//該方法傳入一個待解析的物件 返回該物件的JSON字串
public static String CreateJsonStringbyGson(Object value) {
Gson gson = new Gson();
String Str = gson.toJson(value);
return Str;
} 伺服器端封裝好的返回各種型別JSON字串的方法
public class JsonService {
//一個person物件
public Person getPerson(){
Person person=new Person(1001,"hang","suqian");
return person;
}
public List<Person> getlistPerson(){
List<Person> list=new ArrayList<Person>();
Person person1=new Person(1001,"zhang","suqian");
Person person2=new Person(2002,"hang","yangzhou");
list.add(person1);
list.add(person2);
return list;
}
public List<String> getlistString(){
List<String> list=new ArrayList<String>();
list.add("beijing");
list.add("suqian");
return list;
}
public List<Map<String,Object>> getlistMap(){
List<Map<String,Object>> list=new ArrayList<Map<String,Object>>();
Map<String,Object> map1=new HashMap<String, Object>();
map1.put("id", 1001);
map1.put("name","zhang");
map1.put("address", "beijing");
Map<String,Object> map2=new HashMap<String, Object>();
map2.put("id", 1002);
map2.put("name","hang");
map2.put("address", "shanghai");
list.add(map1);
list.add(map2);
return list;
}
} Android客戶端解析 該工具類封裝瞭解析各種JSON物件的方法
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import com.google.gson.Gson;
import com.google.gson.reflect.TypeToken;
import android.widget.EditText;
public class GsonTools {
public static <T> T getPerson(String jsonString, Class<T> cls) {
T t = null;
try {
Gson gson = new Gson();
t = gson.fromJson(jsonString, cls);
} catch (Exception e) {
e.printStackTrace();
}
return t;
}
public static <T> List<T> getPersons(String jsonString, Class<T> cls) {
List<T> list = new ArrayList<T>();
try {
Gson gson = new Gson();
list = gson.fromJson(jsonString, new TypeToken<List<T>>() {
}.getType());
} catch (Exception e) {
e.printStackTrace();
}
return list;
}
public static List<String> getList(String jsonString) {
List<String> list = new ArrayList<String>();
try {
Gson gson = new Gson();
list = gson.fromJson(jsonString, new TypeToken<List<String>>() {
}.getType());
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
public static List<Map<String,Object>> listKeyMap(String jsonString){
List<Map<String,Object>> list=new ArrayList<Map<String,Object>>();
try {
Gson gson = new Gson();
list = gson.fromJson(jsonString, new TypeToken<List<Map<String,Object>>>() {
}.getType());
} catch (Exception e) {
// TODO: handle exception
}
return list;
}
} 到此就完成了Gson對JSON的解析