Android中使用Retrofit的五种请求方式案例

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/getUser
GET方式，Int参数	GET	Int(id)	/user/getParamUser
Post方式，无参数	POST	无	/user/postNoParamUser
Post方式，有参数	POST	Int(id)	/user/postParamUser
Post方式，Json化参数	POST	Object(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 + '\'' +
                '}';
    }
}