Android开发中 OKHttp的拦截器

拦截器是一种强大的机制,可以监视、重写和重试调用.
拦截器的作用
1.拦截器可以一次性对所有的请求和返回值进行修改。
2.拦截器可以一次性对请求的参数和返回的结果进行编码,比如统一设置为UTF-8.
3.拦截器可以对所有的请求做统一的日志记录,不需要在每个请求开始或者结束的位置都添加一个日志操作。
4.其他需要对请求和返回进行统一处理的需求....
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OkHttp中拦截器分类
OkHttp中的拦截器分2个:
APP层面的拦截器(Application Interception)
Application Interceptor是在请求执行刚开始,还没有执行OkHttp的核心代码前进行拦截,Application拦截器的作用:
1、不需要担心是否影响OKHttp的请求策略和请求速度。
2、即使是从缓存中取数据,也会执行Application拦截器。
3、允许重试,即Chain.proceed()可以执行多次。(当然请不要盲目执行多次,需要加入你的逻辑判断)
网络请求层面的拦截器(Network Interception)
Network Interception是在连接网络之前
1、可以修改OkHttp框架自动添加的一些属性(当然最好不要修改)。

2、可以观察最终完整的请求参数(也就是最终服务器接收到的请求数据和熟悉)

---------------MainActivity---------------------------

package com.example.earl.mylanjieqi;

import android.support.v7.app.AppCompatActivity;
import android.os.Bundle;
import android.util.Log;
import android.view.View;
import android.widget.Button;
import java.io.IOException;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.Response;

public class MainActivity extends AppCompatActivity {

    private Button btn1;
    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main);
        btn1 = findViewById(R.id.bt1);

        btn1.setOnClickListener(new View.OnClickListener() {

            @Override
            public void onClick(View view) {
                //使用拦截器
                OkHttpClient client = new OkHttpClient();
                client.newBuilder().addInterceptor(new MyIntercepter());
                Request re = new Request.Builder().url("http://www.baidu.com").build();
                Call call = client.newCall(re);
                call.enqueue(new Callback() {
                    @Override
                    public void onFailure(Call call, IOException e) {

                    }

                    @Override
                    public void onResponse(Call call, Response response) throws IOException {
                        String server = response.header("Server");
                        Log.d("TAG","--------"+server);
                    }
                });
            }
        });

    }
    class MyIntercepter implements Interceptor {
        @Override
        public Response intercept(Chain chain) throws IOException {
            //自己的逻辑
            //如果访问的是百度改成八维
            //获取请求头
            Request request = chain.request();
            String host = request.url().host();
            if (host.equals("www.baidu.com")){
                host="www.bawei.com";
            }
            //重新创建请求
            Request build = request.newBuilder().url(host).build();

            //让请求去执行
            Response response = chain.proceed(build);

            return response;
        }
    }
}
-------------Main2Activity---------------------
 
  
package com.example.earl.mylanjieqi;

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.EditText;
import java.io.IOException;
import java.util.HashMap;
import okhttp3.Call;
import okhttp3.Callback;
import okhttp3.FormBody;
import okhttp3.Interceptor;
import okhttp3.OkHttpClient;
import okhttp3.Request;
import okhttp3.RequestBody;
import okhttp3.Response;

public class Main2Activity extends AppCompatActivity {

    private EditText mobile;
    private EditText password;
    private Button login;

    @Override
    protected void onCreate(Bundle savedInstanceState) {
        super.onCreate(savedInstanceState);
        setContentView(R.layout.activity_main2);
        mobile = findViewById(R.id.mobile);
        password = findViewById(R.id.password);
        login = findViewById(R.id.login);

        login.setOnClickListener(new View.OnClickListener() {


            @Override
            public void onClick(View view) {
                String m = mobile.getText().toString();
                String p = password.getText().toString();
                Log.d("TAG","点击"+m+"-----"+p);
                //请求网络
                OkHttpClient okHttpClient = new OkHttpClient.Builder().addInterceptor(new MyInterceptor1()).build();
                Log.d("TAG","拦截器注册成");

                FormBody formBody = new FormBody.Builder()
                        .add("mobile", m)
                        .add("password", p)
                        .build();
                Request re = new Request.Builder().url("https://www.zhaoapi.cn/user/login").post(formBody).build();

                //请求队列
                Call call = okHttpClient.newCall(re);
                call.enqueue(new Callback() {
                    @Override
                    public void onFailure(Call call, IOException e) {

                    }

                    @Override
                    public void onResponse(Call call, Response response) throws IOException {
                        Log.d("TAG","okhttp"+"成功-----");
                    }
                });
            }
        });
    }
    class MyInterceptor1 implements Interceptor {
        @Override
        public Response intercept(Chain chain) throws IOException {

            //获取请求体
            Request request = chain.request();
            RequestBody body = request.body();
            Log.d("TAG","拦截器---"+body);

            //获取手机号密码
            HashMap map = new HashMap<>();
            if (body instanceof FormBody)
                //取出
                for (int i = 0; i <((FormBody)body).size() ; i++) {
                    String name=((FormBody)body).name(i);
                    String value=((FormBody)body).value(i);
                    //封装到Map
                    map.put(name,value);
                }
            //打印封装好的map
            Log.d("TAG", "封装完毕--" + map.toString());
            Response proceed = chain.proceed(request);

            return proceed;
        }
    }
}
--------------activity_main------------------------
 
  
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:id="@+id/bt1"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="按钮1"
        />

LinearLayout>
-------------activity_main2-----------------------
 
  
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=".Main2Activity">

    <EditText
        android:id="@+id/mobile"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <EditText
        android:id="@+id/password"
        android:layout_width="match_parent"
        android:layout_height="wrap_content"/>

    <Button
        android:id="@+id/login"
        android:layout_width="wrap_content"
        android:layout_height="wrap_content"
        android:text="登陆"/>

LinearLayout>



 
  

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