Java encapsulates the OkHttp3 utility class for Java backend developers

To be honest, I have used a lot of web request tools, including Java native HttpClient3 and 4, but I feel that after using OkHttp3, I don’t want to use those at all. How to say, the code is light, very flexible to use, very responsive, much easier to use than HttpClient. Of course, these are my personal opinions, do not like to spray.

The preparatory work

The Maven project introduces jar packages in POM files

< the dependency > < groupId > com. Squareup. Okhttp3 < / groupId > < artifactId > okhttp < / artifactId > < version > 3.10.0 < / version > </dependency> <groupId>com.alibaba</groupId> <artifactId>fastjson</artifactId> <version>1.2.60</version> </dependency>Copy the code

Json was introduced because it is used in some places in the utility class, and it is now popular for communication to use JSON transport, as well as this JAR package

Utility class code

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;

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);

    }
}
Copy the code

Using the tutorial

Public static void main(String[] args) {public static void main(String[] args) {public static void main(String[] args) { Okhttputils.builder ().url(" request address, HTTP/HTTPS can be used ") AddParam (" parameter name ", "parameter value "). AddParam (" parameter name "," parameter value ") // You can add multiple. AddHeader (" content-type ", "application/json; Charset = utF-8 ").get() // async(); .sync(); Okhttputils.builder ().url(" request address, HTTP/HTTPS can be used ") AddParam (" parameter name ", "parameter value "). AddParam (" parameter name "," parameter value ") // You can add multiple. AddHeader (" content-type ", "application/json; Charset = utF-8 ") // If true, this will be similar to the postman raw submission, json submission, not a form // If false, the traditional form submission.post(true).sync(); Okhttputils.builder ().url("").post(false).async(); OkHttpUtils.builder().url("").post(false).async(new OkHttpUtils.ICallBack() { @Override public void onSuccessful(Call Call, String data) {Override public void onFailure(call call, String errorMsg) {// Handle request failure}}); }Copy the code

conclusion

The package is clear, the usage is simple, the request can be done in a few clicks, and the builder mode is really comfortable

Author: Such as vortex source: blog.csdn.net/m0_37701381