Android中使用Retrofit的五种请求方式案例

目录

说明一、环境搭建1.导入依赖2.打开网络权限 二、布局三、GET请求1.无参GET请求2.有参GET请求 四、POST请求1.无参POST请求2.有参POST请求3.发送Json化POST请求 四、代码总结

说明

沿用上一次网络请求接口 接口入口

接口文档

说明请求方式请求参数请求地址GET 方式，无参数GET无/user/getUserGET方式，Int参数GETInt(id)/user/getParamUserPost方式，无参数POST无/user/postNoParamUserPost方式，有参数POSTInt(id)/user/postParamUserPost方式，Json化参数POSTObject(id，name，sex，studentId，sex，data)/user/postObjectParamUser

一、环境搭建

1.导入依赖

//Retrofit（网络请求框架） implementation 'com.squareup.retrofit2:retrofit:2.5.0' implementation 'com.squareup.retrofit2:converter-gson:2.5.0'

注意：这里不能导入OkHttp与Gson，Retrofit内部已经包含这两个框架，否则会导致版本冲突。

2.打开网络权限

<uses-permission android:name="android.permission.INTERNET"></uses-permission>

在 AndroidManifest中打开网络权限 ,注意：如果请求的地址为Http协议则需要在application中加入： android:usesCleartextTraffic=“true” 设置http为可用，默认只可以请求https请求。

二、布局

<?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" tools:context=".MainActivity"> <Button android:layout_width="match_parent" android:id="@+id/sendGetNotParam" android:text="发送GET无参请求" android:layout_height="wrap_content"/> <Button android:layout_width="match_parent" android:id="@+id/sendGetHaveParam" android:text="发送GET有参请求" android:layout_height="wrap_content"/> <Button android:layout_width="match_parent" android:id="@+id/sendPostNotParam" android:text="发送POST无参请求" android:layout_height="wrap_content"/> <Button android:layout_width="match_parent" android:text="发送POST有参请求" android:id="@+id/sendPostHaveParam" android:layout_height="wrap_content"/> <Button android:layout_width="match_parent" android:text="发送POSTJson化请求" android:id="@+id/sendPostJsonParam" android:layout_height="wrap_content"/> <TextView android:layout_width="match_parent" android:layout_height="wrap_content" android:textStyle="bold" android:textSize="24sp" android:id="@+id/main_text" android:layout_marginTop="20dp" android:text="Hello World!" /> </LinearLayout>

准备工作

Retrofit retrofit = new Retrofit.Builder() /*必须以 '/' 结束*/ .baseUrl("你的接口地址 以 / 结尾") /*将返回的数据转换为Gson*/ .addConverterFactory(GsonConverterFactory.create()) .build(); /* 需要写一个专门的接口类 */ apiService = retrofit.create(ApiService.class);

三、GET请求

1.无参GET请求

接口，注意：注解必须写入参数，没有参数时可以使用 . 或 /

//没有数据就填 '.' 或者 '/' @GET("getUser") Call<User> getUser();

代码实现

apiService.getUser().enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } });

2.有参GET请求

接口,GET请求的参数使用@Query注解

/*有参GET请求 */ @GET("getParamUser") Call<User>getParamUser(@Query("id") int id); apiService.getParamUser(2).enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } });

四、POST请求

1.无参POST请求

接口

/*无参POST请求 */ @POST("postNoParamUser") Call<User>postNoParamUser(); apiService.postNoParamUser().enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } });

2.有参POST请求

发送表单化参数，必须要带上注解@FormUrlEncoded 且，参数必须带上参数@Field注解

/*有参POST请求 */ @FormUrlEncoded @POST("postParamUser") Call<User> postParamUser(@Field("id") int id); apiService.postParamUser(13).enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } });

3.发送Json化POST请求

使用Json化参数 必须去掉注解@FormUrlEncoded 且，参数中必须使用@Body注解

/*JSON化参数POST请求 */ @POST("postObjectParamUser") Call<User>postObjectParamUser(@Body User user); User user = new User(); user.setName("顺顺萌新"); user.setStudentId("123456"); user.setData("我是提示数据"); user.setSex("萌新"); user.setId(1); apiService.postObjectParamUser(user).enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } });

四、代码总结

MainActivity代码

package com.example.secode; import android.os.Bundle; import android.util.Log; import android.view.View; import android.widget.Button; import android.widget.TextView; import androidx.appcompat.app.AppCompatActivity; import retrofit2.Call; import retrofit2.Callback; import retrofit2.Response; import retrofit2.Retrofit; import retrofit2.converter.gson.GsonConverterFactory; public class MainActivity extends AppCompatActivity implements View.OnClickListener { private Retrofit retrofit; private ApiService apiService; private Button sendGetNotParam; private Button sendGetHaveParam; private Button sendPostNotParam; private Button sendPostHaveParam; private Button sendPostJsonParam; private static final String TAG = "用户打印信息"; private TextView mainText; @Override protected void onCreate(Bundle savedInstanceState) { super.onCreate(savedInstanceState); setContentView(R.layout.activity_main); retrofit = new Retrofit.Builder() /*必须以 '/' 结束*/ .baseUrl("你的地址，必须以 / 结尾") /*将返回的数据转换为Gson*/ .addConverterFactory(GsonConverterFactory.create()) .build(); /* 需要写一个专门的接口类 */ apiService = retrofit.create(ApiService.class); initView(); } private void initView() { sendGetNotParam = (Button) findViewById(R.id.sendGetNotParam); sendGetHaveParam = (Button) findViewById(R.id.sendGetHaveParam); sendPostNotParam = (Button) findViewById(R.id.sendPostNotParam); sendPostHaveParam = (Button) findViewById(R.id.sendPostHaveParam); sendPostJsonParam = (Button) findViewById(R.id.sendPostJsonParam); sendGetNotParam.setOnClickListener(this); sendGetHaveParam.setOnClickListener(this); sendPostNotParam.setOnClickListener(this); sendPostHaveParam.setOnClickListener(this); sendPostJsonParam.setOnClickListener(this); mainText = (TextView) findViewById(R.id.main_text); mainText.setOnClickListener(this); } @Override public void onClick(View v) { switch (v.getId()) { case R.id.sendGetNotParam: apiService.getUser().enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } }); break; case R.id.sendGetHaveParam: apiService.getParamUser(2).enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } }); break; case R.id.sendPostNotParam: apiService.postNoParamUser().enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } }); break; case R.id.sendPostHaveParam: apiService.postParamUser(13).enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } }); break; case R.id.sendPostJsonParam: User user = new User(); user.setName("顺顺萌新"); user.setStudentId("123456"); user.setData("我是提示数据"); user.setSex("萌新"); user.setId(1); apiService.postObjectParamUser(user).enqueue(new Callback<User>() { @Override public void onResponse(Call<User> call, Response<User> response) { User user = response.body(); mainText.setText(user.toString()); } @Override public void onFailure(Call<User> call, Throwable t) { } }); break; } } }

ApiService请求接口

package com.example.secode; import retrofit2.Call; import retrofit2.http.Body; import retrofit2.http.Field; import retrofit2.http.FormUrlEncoded; import retrofit2.http.GET; import retrofit2.http.POST; import retrofit2.http.Query; public interface ApiService { /*无参GET请求 */ //没有数据就填 '.' 或者 '/' @GET("getUser") Call<User> getUser(); /*有参GET请求 */ @GET("getParamUser") Call<User>getParamUser(@Query("id") int id); /*无参POST请求 */ @POST("postNoParamUser") Call<User>postNoParamUser(); /*有参POST请求 */ @FormUrlEncoded @POST("postParamUser") Call<User> postParamUser(@Field("id") int id); /*JSON化参数POST请求 */ @POST("postObjectParamUser") Call<User>postObjectParamUser(@Body User user); }

User实体类

package com.example.secode; public class User { private int id; private String name; private String studentId; private String sex; private String data; public int getId() { return id; } public void setId(int id) { this.id = id; } public String getName() { return name; } public void setName(String name) { this.name = name; } public String getStudentId() { return studentId; } public void setStudentId(String studentId) { this.studentId = studentId; } public String getSex() { return sex; } public void setSex(String sex) { this.sex = sex; } public String getData() { return data; } public void setData(String data) { this.data = data; } @Override public String toString() { return "User{" + "id=" + id + ", name='" + name + '\'' + ", studentId='" + studentId + '\'' + ", sex='" + sex + '\'' + ", data='" + data + '\'' + '}'; } }