OkHttp入门学习

参考教程：
https://www.baeldung.com/guide-to-okhttp
https://zhuanlan.zhihu.com/p/337000646

依赖引入

 <dependency>
            <groupId>com.squareup.okhttp3</groupId>
            <artifactId>okhttp</artifactId>
            <version>3.6.0</version>
        </dependency>

        <dependency>
            <groupId>com.alibaba</groupId>
            <artifactId>fastjson</artifactId>
            <version>1.2.83</version>
        </dependency>

        <dependency>
            <groupId>org.projectlombok</groupId>
            <artifactId>lombok</artifactId>
            <version>1.18.24</version>
        </dependency>

get同步请求与异步请求

package com.mrs.main;

import lombok.extern.slf4j.Slf4j;
import okhttp3.*;

import java.io.IOException;

/**
 * description: GetDemo
 * date: 2022/9/7 18:56
 * author: MR.孙
 */
@Slf4j
public class GetDemo {
    public static void main(String[] args) {
        //使用 OkHttp 同步 GET
        synchronization();
        //使用OkHttp 异步请求GET
        asynchronous();
    }

    /**
     * @description: 异步请求GET
     * @return: void
     * @author: MR.孙
     * @date: 2022/9/7 19:14
    */
    private static void asynchronous() {
        //1.创建OkHttpClient对象
        OkHttpClient client = new OkHttpClient();

        //2.设置请求
        Request request = new Request.Builder()
                .url("https://www.baidu.com")
                .build();

        //3.封装call
        Call call = client.newCall(request);
        //4.异步调用，并设置回调函数
        call.enqueue(new Callback() {
            public void onFailure(Call call, IOException e) {
                log.info("异步get请求发送失败");
            }

            public void onResponse(Call call, Response response) throws IOException {
                if(response!=null && response.isSuccessful()){
                    log.info("异步get请求发送成功");
                }
            }
        });

    }

    /**
     * @description:  同步get请求
     * @return: void
     * @author: MR.孙
     * @date: 2022/9/7 19:12
    */
    private static void synchronization() {
        //1.创建okHttp对象
        OkHttpClient client = new OkHttpClient();

        //2.设置请求
        Request request = new Request.Builder()
                .url("https://www.baidu.com")
                .build();

        //3.封装call
        Call call = client.newCall(request);

        try {
            Response execute = call.execute();
            System.out.println(execute.toString());
        } catch (IOException e) {
            e.printStackTrace();
        }
    }
}

post同步请求和异步请求

form形式和json参数形式

package com.mrs.main;

import com.alibaba.fastjson.JSON;
import com.mrs.entity.User;
import lombok.extern.slf4j.Slf4j;
import okhttp3.*;

import java.io.IOException;


/**
 * description: PostDemo
 * date: 2022/9/7 22:31
 * author: MR.孙
 */
@Slf4j
public class PostDemo {
    public static void main(String[] args) {
        //Post异步请求请求 form表单形式
        getsysn("https://www.wanandroid.com/user/login");

        //Post异步请求请求 form表单形式
        getAsyn("https://www.wanandroid.com/user/login");

        // json参数形式
        User user = new User();
        user.setUsername("slzgg666");
        user.setPassword("123456");
        String json = JSON.toJSONString(user);
        // System.out.println(json);
        //    {"password":"123456","username":"slzgg666"}
        getJsonParams("https://www.wanandroid.com/user/login",json);



    }

    private static void getJsonParams(String url,String json) {
        //创建OkHttpClient
        OkHttpClient client = new OkHttpClient();

        //构建参数
        RequestBody requestBody = RequestBody.create(MediaType.parse("application/json;charset=utf-8"), json);

        //构建request
        Request request = new Request.Builder()
                .url(url)
                .post(requestBody)
                .build();

        //将request封装成Call
        Call call = client.newCall(request);
        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                log.info("发送表单数据失败");
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if(response !=null && response.isSuccessful()){
                    log.info("响应体内容为:->{}", response.body().string());

                }
            }
        });
    }

    private static void getsysn(String url) {
        //创建OkHttpClient对象
        OkHttpClient client = new OkHttpClient();

        //创建FormBody对象构建参数
        FormBody formBody = new FormBody.Builder()
                .add("username", "slzgg666")
                .add("password", "123456")
                .build();
        //构建request
        Request request = new Request.Builder()
                .url(url)
                .post(formBody)
                .build();

        //封装Call
        Call call = client.newCall(request);
        try {
            Response response = call.execute();
            log.info("响应体内容为:->{}",response.body().string());
        } catch (Exception e) {
            e.printStackTrace();
        }

    }

    private static void getAsyn(String url) {
        //创建OkHttpClient对象
        OkHttpClient client = new OkHttpClient();
        //构建参数
        FormBody formBody = new FormBody.Builder()
                .add("username", "slzgg666")
                .add("password", "123456")
                .build();

        //构建 request
        Request request = new Request.Builder()
                .url(url)
                .post(formBody)
                .build();
        //封装Call
        Call call = client.newCall(request);

        call.enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                log.info("发送表单数据失败");
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if (response!=null && response.isSuccessful()){
                    log.info("响应体内容为:->{}", response.body().string());
                }
            }
        });
    }
}

文件上传

package com.mrs.main;

import lombok.extern.slf4j.Slf4j;
import okhttp3.*;

import java.io.*;

/**
 * description: DownloadDemo
 * date: 2022/9/7 23:32
 * author: MR.孙
 */
@Slf4j
public class DownloadDemo {
    public static void main(String[] args) {
        //文件下载
        download("https://img2.baidu.com/it/u=4216378944,3643750935&fm=253&fmt=auto&app=120&f=JPEG?w=1600&h=683"
                ,"D:\\file\\","img1.jpg");
    }
    private static void download(String url, String target, String fileName) {
        //1.获取okHttpClient对象
        OkHttpClient client = new OkHttpClient();
        //2.构建request
        Request request = new Request.Builder()
                .url(url)
                .build();
        //3.异步调用
        client.newCall(request).enqueue(new Callback() {
            @Override
            public void onFailure(Call call, IOException e) {
                e.printStackTrace();
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
                if(response.isSuccessful()){
                    //4.文件下载
                    downloadFile(response,target,fileName);
                }
            }
        });

    }

    private static void downloadFile(Response response, String target, String fileName) {
        InputStream inputStream = null;
        byte[] buf = new byte[1024*1024*1024];
        int len = 0;
        FileOutputStream outputStream = null;

         inputStream = response.body().byteStream();
         //文件大小
        long total = response.body().contentLength();
        System.out.println(total);
        File file = new File(target + fileName);
        try {
            outputStream = new FileOutputStream(file);
            while((len=inputStream.read(buf))!=-1){
                outputStream.write(buf,0,len);
            }
            outputStream.flush();
        } catch (Exception e) {
            e.printStackTrace();
        }finally {

                try {
                    if(inputStream!=null)  inputStream.close();
                    if(outputStream!=null) outputStream.close();
                } catch (IOException e) {
                    e.printStackTrace();
                }

        }

    }
}