1.開發環境
客戶端:Android Studio 3.0.1
服務端:Eclipse
2.客戶端
(1)AS新建一個項目,然後要使用Retrofit2.0 添加依賴和權限
//retrofit2 依賴庫
implementation 'com.squareup.retrofit2:retrofit:2.4.0'
//Gson 數據解析器依賴庫
implementation 'com.squareup.retrofit2:converter-gson:2.4.0'
//網絡權限
<uses-permission android:name="android.permission.INTERNET"/>
(2)寫一個請求的接口
package com.example.nn.retrofitexample2;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.http.GET;
import retrofit2.http.Query;
/**
* Created by nn on 2019/7/17.
*/
//完整的請求URL爲:http://192.168.94.1:8080/retrofit/retrofitservice?retrofit=xx
public interface RetrofitRequest {
@GET("retrofit/retrofitservice")
//java對象
Call<User> getData(@Query("retrofit") String retrofit);
}
(3)編寫一個實體類
package com.example.nn.retrofitexample2;
/**
* Created by nn on 2019/7/17.
*/
public class User {
private String name;
private String sex;
public User(String name,String sex) {
this.name = name;
this.sex = sex;
}
public String getName() {
return name;
}
public String getSex() {
return sex;
}
}
(4)編寫MainActivity中的代碼
package com.example.nn.retrofitexample2;
import android.os.*;
import android.support.v7.app.AppCompatActivity;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.TextView;
import java.io.IOException;
import java.util.List;
import okhttp3.ResponseBody;
import retrofit2.Call;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class MainActivity extends AppCompatActivity {
private TextView mshow;
private Button mrequest;
public static final String API_SERVICE = "http://192.168.94.1:8080/";
private Handler handler = new Handler(){
@Override
public void handleMessage(Message msg) {
super.handleMessage(msg);
Bundle data = msg.getData();
String result = data.getString("result");
mshow.setText(result);
}
};
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
//初始化控件
init();
mrequest.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Thread(runnable).start(); //不能在UI線程中進行網絡請求
}
});
}
private void init(){
mshow = (TextView)findViewById(R.id.show);
mrequest = (Button)findViewById(R.id.request);
}
//發送網絡請求
private String request() throws IOException {
//創建Retrofit對象
Retrofit retrofit = new Retrofit.Builder()
.baseUrl(API_SERVICE)
.addConverterFactory(GsonConverterFactory.create())
.build();
//創建網絡接口實例
RetrofitRequest retrofitRequest = retrofit.create(RetrofitRequest.class);
//對發送請求進行封裝
Call<User> call = retrofitRequest.getData("REQUEST");
//發送請求,獲取請求的數據
User user = call.execute().body();
StringBuilder result = new StringBuilder();
result.append("姓名:"+user.getName()+" 性別:"+user.getSex());
return result.toString();
}
//網絡請求線程
Runnable runnable = new Runnable() {
@Override
public void run() {
try {
String result = request();
Message msg = new Message();
Bundle data = new Bundle();
data.putString("result", result);
msg.setData(data);
handler.sendMessage(msg);
} catch (IOException e) {
Log.e("request_erro", e.toString());
}
}
};
}
(5)activity_main.xml 的代碼
<?xml version="1.0" encoding="utf-8"?>
<LinearLayout xmlns:android="http://schemas.android.com/apk/res/android"
xmlns:app="http://schemas.android.com/apk/res-auto"
xmlns:tools="http://schemas.android.com/tools"
android:layout_width="match_parent"
android:layout_height="match_parent"
android:orientation="vertical"
android:gravity="center"
tools:context="com.example.nn.retrofitexample2.MainActivity">
<TextView
android:id="@+id/show"
android:layout_width="wrap_content"
android:layout_height="wrap_content" />
<Button
android:id="@+id/request"
android:layout_width="wrap_content"
android:layout_height="wrap_content"
android:text="請求"/>
</LinearLayout>
3.服務端
(1)
打開eclipse建立一個動態的web項目,在src下面建立 一個 retrofit的包,在這個包裏面建立一個servlet,名字爲:retrofitservice
代碼如下:
package com.example.service;
import java.io.IOException;
import javax.servlet.ServletException;
import javax.servlet.annotation.WebServlet;
import javax.servlet.http.HttpServlet;
import javax.servlet.http.HttpServletRequest;
import javax.servlet.http.HttpServletResponse;
import com.example.entity.User;
import net.sf.json.JSONObject;
/**
* Servlet implementation class retrofitservice
*/
@WebServlet("/retrofitservice")
public class retrofitservice extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public retrofitservice() {
super();
// TODO Auto-generated constructor stub
}
/**
* @see HttpServlet#doGet(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doGet(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
request.setCharacterEncoding("utf-8");
response.setCharacterEncoding("utf-8");
response.setContentType("text/html;charset=utf-8");
User user = new User("wenjian","man");
//獲得請求的數據
String message = request.getParameter("retrofit");
if (message.equals("REQUEST")) {
//JAVA對象轉爲JSON對象,然後轉爲JSON字符串
JSONObject object = JSONObject.fromObject(user);
message = object.toString();
}
System.out.println(message);
//返回數據
response.getWriter().append(message);
}
/**
* @see HttpServlet#doPost(HttpServletRequest request, HttpServletResponse
* response)
*/
protected void doPost(HttpServletRequest request, HttpServletResponse response)
throws ServletException, IOException {
// TODO Auto-generated method stub
doGet(request, response);
}
}
(2)
實體類的代碼
package com.example.entity;
public class User {
private String name;
private String sex;
public User() {
}
public User(String name, String sex) {
this.name = name;
this.sex = sex;
}
public String getName() {
return name;
}
public String getSex() {
return sex;
}
public void setName(String name) {
this.name = name;
}
public void setSex(String sex) {
this.sex = sex;
}
}
4.JAVA對象和JSON的轉換
JSON字符串與java對象的轉換
(1) 把java對象列表轉換爲json對象數組,並轉爲字符串
JSONArray array = JSONArray.fromObject(list);
String jsonstr = array.toString();
(2) 把java對象轉換成json對象,並轉化爲字符串
JSONObject object = JSONObject.fromObject(user);
Log4jInit.ysulogger.debug(object.toString());
(3) 把JSON字符串轉換爲JAVA對象數組
JSONArray json = JSONArray.fromObject(userStr);//userStr是json字符串
List<User> users= (List<User>)JSONArray.toCollection(json,User.class);
(4) 把JSON字符串轉換爲JAVA 對象
JSONObject jsonobject = JSONObject.fromObject(jsonStr);
User user= (User)JSONObject.toBean(object,User.class);
5.JSON所需的包
鏈接:https://pan.baidu.com/s/1Q8LNwn151VDkGPPGgWWgPw
提取碼:mv8w
複製這段內容後打開百度網盤手機App,操作更方便哦
6.項目結構
7.運行結果