OkHttp工具类封装，更优雅的调用接口

一、前言

相比较于HttpClient3和4优点是代码轻便，使用起来灵活，响应很快，OkHttp已经被来越被Java开发工程师所青睐，为了更好更直白的调用三方接口，封装OkHttp工具类便一劳永逸。

二、代码(开箱即用)

1、Maven项目在pom文件中引入jar包

<dependency>
    <groupId>com.squareup.okhttp3</groupId>
    <artifactId>okhttp</artifactId>
    <version>3.10.0</version>
</dependency>
<dependency>
    <groupId>com.alibaba</groupId>
    <artifactId>fastjson</artifactId>
    <version>1.2.60</version>
</dependency>

2、代码工具类编写（附带Main方法测试）

package com.dai.okhttp.util;

import com.alibaba.fastjson.JSON;
import okhttp3.*;

import javax.net.ssl.SSLContext;
import javax.net.ssl.SSLSocketFactory;
import javax.net.ssl.TrustManager;
import javax.net.ssl.X509TrustManager;
import java.io.IOException;
import java.net.URLEncoder;
import java.security.SecureRandom;
import java.security.cert.X509Certificate;
import java.util.LinkedHashMap;
import java.util.Map;
import java.util.concurrent.Semaphore;
import java.util.concurrent.TimeUnit;

/** * @ProjectName: LocalDemo * @Package: com.dai.okhttp.util * @ClassName: OkHttpUtils * @Author: Administrator * @Description: OkHttpUtils工具类 * @Date: 2022/2/3 13:26 * @Version: 1.0 */
public class OkHttpUtils {
   

    private static volatile OkHttpClient okHttpClient = null;
    private static volatile Semaphore semaphore = null;
    private Map<String, String> headerMap;
    private Map<String, String> paramMap;
    private String url;
    private Request.Builder request;

    /** * 初始化okHttpClient，并且允许https访问 */
    private OkHttpUtils() {
   
        if (okHttpClient == null) {
   
            synchronized (OkHttpUtils.class) {
   
                if (okHttpClient == null) {
   
                    TrustManager[] trustManagers = buildTrustManagers();
                    okHttpClient = new OkHttpClient.Builder()
                            .connectTimeout(15, TimeUnit.SECONDS)
                            .writeTimeout(20, TimeUnit.SECONDS)
                            .readTimeout(20, TimeUnit.SECONDS)
                            .sslSocketFactory(createSSLSocketFactory(trustManagers), (X509TrustManager) trustManagers[0])
                            .hostnameVerifier((hostName, session) -> true)
                            .retryOnConnectionFailure(true)
                            .build();
                    addHeader("User-Agent", "Mozilla/5.0 (Macintosh; Intel Mac OS X 10_12_6) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/63.0.3239.132 Safari/537.36");
                }
            }
        }
    }

    /** * 用于异步请求时，控制访问线程数，返回结果 * * @return */
    private static Semaphore getSemaphoreInstance() {
   
        //只能1个线程同时访问
        synchronized (OkHttpUtils.class) {
   
            if (semaphore == null) {
   
                semaphore = new Semaphore(0);
            }
        }
        return semaphore;
    }

    /** * 创建OkHttpUtils * * @return */
    public static OkHttpUtils builder() {
   
        return new OkHttpUtils();
    }

    /** * 添加url * * @param url * @return */
    public OkHttpUtils url(String url) {
   
        this.url = url;
        return this;
    }

    /** * 添加参数 * * @param key 参数名 * @param value 参数值 * @return */
    public OkHttpUtils addParam(String key, String value) {
   
        if (paramMap == null) {
   
            paramMap = new LinkedHashMap<>(16);
        }
        paramMap.put(key, value);
        return this;
    }

    /** * 添加请求头 * * @param key 参数名 * @param value 参数值 * @return */
    public OkHttpUtils addHeader(String key, String value) {
   
        if (headerMap == null) {
   
            headerMap = new LinkedHashMap<>(16);
        }
        headerMap.put(key, value);
        return this;
    }

    /** * 初始化get方法 * * @return */
    public OkHttpUtils get() {
   
        request = new Request.Builder().get();
        StringBuilder urlBuilder = new StringBuilder(url);
        if (paramMap != null) {
   
            urlBuilder.append("?");
            try {
   
                for (Map.Entry<String, String> entry : paramMap.entrySet()) {
   
                    urlBuilder.append(URLEncoder.encode(entry.getKey(), "utf-8")).
                            append("=").
                            append(URLEncoder.encode(entry.getValue(), "utf-8")).
                            append("&");
                }
            } catch (Exception e) {
   
                e.printStackTrace();
            }
            urlBuilder.deleteCharAt(urlBuilder.length() - 1);
        }
        request.url(urlBuilder.toString());
        return this;
    }

    /** * 初始化post方法 * * @param isJsonPost true等于json的方式提交数据，类似postman里post方法的raw * false等于普通的表单提交 * @return */
    public OkHttpUtils post(boolean isJsonPost) {
   
        RequestBody requestBody;
        if (isJsonPost) {
   
            String json = "";
            if (paramMap != null) {
   
                json = JSON.toJSONString(paramMap);
            }
            requestBody = RequestBody.create(MediaType.parse("application/json; charset=utf-8"), json);
        } else {
   
            FormBody.Builder formBody = new FormBody.Builder();
            if (paramMap != null) {
   
                paramMap.forEach(formBody::add);
            }
            requestBody = formBody.build();
        }
        request = new Request.Builder().post(requestBody).url(url);
        return this;
    }

    /** * 同步请求 * * @return */
    public String sync() {
   
        setHeader(request);
        try {
   
            Response response = okHttpClient.newCall(request.build()).execute();
            assert response.body() != null;
            return response.body().string();
        } catch (IOException e) {
   
            e.printStackTrace();
            return "请求失败：" + e.getMessage();
        }
    }

    /** * 异步请求，有返回值 */
    public String async() {
   
        StringBuilder buffer = new StringBuilder("");
        setHeader(request);
        okHttpClient.newCall(request.build()).enqueue(new Callback() {
   
            @Override
            public void onFailure(Call call, IOException e) {
   
                buffer.append("请求出错：").append(e.getMessage());
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
   
                assert response.body() != null;
                buffer.append(response.body().string());
                getSemaphoreInstance().release();
            }
        });
        try {
   
            getSemaphoreInstance().acquire();
        } catch (InterruptedException e) {
   
            e.printStackTrace();
        }
        return buffer.toString();
    }

    /** * 异步请求，带有接口回调 * * @param callBack */
    public void async(ICallBack callBack) {
   
        setHeader(request);
        okHttpClient.newCall(request.build()).enqueue(new Callback() {
   
            @Override
            public void onFailure(Call call, IOException e) {
   
                callBack.onFailure(call, e.getMessage());
            }

            @Override
            public void onResponse(Call call, Response response) throws IOException {
   
                assert response.body() != null;
                callBack.onSuccessful(call, response.body().string());
            }
        });
    }

    /** * 为request添加请求头 * * @param request */
    private void setHeader(Request.Builder request) {
   
        if (headerMap != null) {
   
            try {
   
                for (Map.Entry<String, String> entry : headerMap.entrySet()) {
   
                    request.addHeader(entry.getKey(), entry.getValue());
                }
            } catch (Exception e) {
   
                e.printStackTrace();
            }
        }
    }


    /** * 生成安全套接字工厂，用于https请求的证书跳过 * * @return */
    private static SSLSocketFactory createSSLSocketFactory(TrustManager[] trustAllCerts) {
   
        SSLSocketFactory ssfFactory = null;
        try {
   
            SSLContext sc = SSLContext.getInstance("SSL");
            sc.init(null, trustAllCerts, new SecureRandom());
            ssfFactory = sc.getSocketFactory();
        } catch (Exception e) {
   
            e.printStackTrace();
        }
        return ssfFactory;
    }

    private static TrustManager[] buildTrustManagers() {
   
        return new TrustManager[]{
   
                new X509TrustManager() {
   
                    @Override
                    public void checkClientTrusted(X509Certificate[] chain, String authType) {
   
                    }

                    @Override
                    public void checkServerTrusted(X509Certificate[] chain, String authType) {
   
                    }

                    @Override
                    public X509Certificate[] getAcceptedIssuers() {
   
                        return new X509Certificate[]{
   };
                    }
                }
        };
    }

    /** * 自定义一个接口回调 */
    public interface ICallBack {
   

        void onSuccessful(Call call, String data);

        void onFailure(Call call, String errorMsg);

    }

    public static void main(String[] args) {
   
        // get请求，方法顺序按照这种方式，切记选择post/get一定要放在倒数第二，同步或者异步倒数第一，才会正确执行
        OkHttpUtils.builder().url("请求地址，http/https都可以")
                // 有参数的话添加参数，可多个
                .addParam("参数名", "参数值")
                .addParam("参数名", "参数值")
                // 也可以添加多个
                .addHeader("Content-Type", "application/json; charset=utf-8")
                .get()
                // 可选择是同步请求还是异步请求
                //.async();
                .sync();

        // post请求，分为两种，一种是普通表单提交，一种是json提交
        OkHttpUtils.builder().url("请求地址，http/https都可以")
                // 有参数的话添加参数，可多个
                .addParam("参数名", "参数值")
                .addParam("参数名", "参数值")
                // 也可以添加多个
                .addHeader("Content-Type", "application/json; charset=utf-8")
                // 如果是true的话，会类似于postman中post提交方式的raw，用json的方式提交，不是表单
                // 如果是false的话传统的表单提交
                .post(true)
                .sync();

        // 选择异步有两个方法，一个是带回调接口，一个是直接返回结果
        OkHttpUtils.builder().url("")
                .post(false)
                .async();

        OkHttpUtils.builder().url("").post(false).async(new OkHttpUtils.ICallBack() {
   
            @Override
            public void onSuccessful(Call call, String data) {
   
                // 请求成功后的处理
            }

            @Override
            public void onFailure(Call call, String errorMsg) {
   
                // 请求失败后的处理
            }
        });
    }
}