今天学习了Retrofit2,完成了一个简单的RetrofitDemo
先总结一下踩到的坑或潜在的坑
1.配置网络权限
<uses-permission android:name="android.permission.INTERNET"/>
2.添加依赖
compile 'com.squareup.retrofit2:retrofit:2.0.2'
compile 'com.squareup.retrofit2:converter-gson:2.0.2'
3.Gson jar 包
服务器需要一个json jar包打包成json数据
4.注意服务器端返回的json数据格式是否正确
特别注意,要查看自己输出流,输出的数据是否正确,我今天就踩了一个大坑,创建servlet的时候
它自动的给我写了一个这玩意,我的天,我就一直纳闷它老是走onFailure,大家一定要特别注意。
response.getWriter().append("Served at: ").append(request.getContextPath());
下面的是对象的正确的json格式
{"A":"1","B":"1"}
java 服务器端代码
model 服务器和客户端都要有
package com.example.retrofit2study.model;
/**
* Created by 粽子 on 2018/7/9.
*/
public class User {
private String A;
private String B;
public String getA() {
return A;
}
public String getB() {
return B;
}
public void setA(String a) {
A = a;
}
public void setB(String b) {
B = b;
}
}
servlet
package servelt;
import java.io.IOException;
import java.io.PrintWriter;
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.google.gson.Gson;
import com.sun.xml.internal.bind.v2.schemagen.xmlschema.List;
/**
* Servlet implementation class LoginServelt
*/
@WebServlet("/LoginServelt")
public class LoginServelt extends HttpServlet {
private static final long serialVersionUID = 1L;
/**
* @see HttpServlet#HttpServlet()
*/
public LoginServelt() {
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
response.setCharacterEncoding("utf-8");
request.setCharacterEncoding("utf-8");
response.setContentType("application/json; charset=utf-8");
System.out.println("有访问");
PrintWriter out = response.getWriter();
User user=new User();
user.setA("1");
user.setB("1");
Gson gson = new Gson();
String aa=gson.toJson(user);
out.write(aa);
out.flush();
out.close();
System.out.println(aa);
}
/**
* @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);
}
}
客户端
接口
package com.example.retrofit2study.net;
import com.example.retrofit2study.model.User;
import java.util.List;
import retrofit2.Call;
import retrofit2.http.GET;
/**
* Created by 粽子 on 2018/7/9.
*/
public interface GetUserService {
@GET("LoginServelt")
Call<User> getUser();
}
package com.example.retrofit2study;
import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import android.widget.Toast;
import com.example.retrofit2study.model.User;
import com.example.retrofit2study.net.GetUserService;
import java.util.List;
import java.util.StringTokenizer;
import retrofit2.Call;
import retrofit2.Callback;
import retrofit2.Response;
import retrofit2.Retrofit;
import retrofit2.converter.gson.GsonConverterFactory;
public class MainActivity extends AppCompatActivity {
@Override
protected void onCreate(Bundle savedInstanceState) {
super.onCreate(savedInstanceState);
setContentView(R.layout.activity_main);
Button button= (Button) findViewById(R.id.button1);
button.setOnClickListener(new View.OnClickListener() {
@Override
public void onClick(View v) {
new Thread(new Runnable() {
@Override
public void run() {
Retrofit retrofit=new Retrofit.Builder()
.baseUrl("http://地址:8080/Retrofit2Study/")//这里填你自己的地址
.addConverterFactory(GsonConverterFactory.create())
.build();
GetUserService getUserService=retrofit.create(GetUserService.class);
Call<User> call=getUserService.getUser();
call.enqueue(new Callback<User>() {
@Override
public void onResponse(Call<User> call, Response<User> response) {
Toast.makeText(MainActivity.this,"结果"+response.body(),Toast.LENGTH_SHORT).show();
}
@Override
public void onFailure(Call<User> call, Throwable t) {
Toast.makeText(MainActivity.this,"结果失败",Toast.LENGTH_SHORT).show();
}
});
}
}).start();
}
});
}
}
layout就一个按钮 id为 button1