目录

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 + '\'' +
                '}';
    }
}