Java中的OkHttp使用教程

Java中的OkHttp使用教程

目录什么是OKHttpOkHttp基本使用添加依赖OkHttp工具类使用案例发送get请求发送Post请求发送异步请求

什么是OKHttp

一般在java平台上，我们会使用Apache HttpClient作为Http客户端，用于发送 HTTP 请求，并对响应进行处理。比如可以使用http客户端与第三方服务(如SSO服务)进行集成，当然还可以爬取网上的数据等。OKHttp与HttpClient类似，也是一个Http客户端，提供了对 HTTP/2 和 SPDY 的支持，并提供了连接池，GZIP 压缩和 HTTP 响应缓存功能；

OkHttp是目前非常火的网络库，它有以下特性：

1.支持HTTP/2，允许所有同一个主机地址的请求共享同一个socket连接

2.连接池减少请求延时

3.透明的GZIP压缩减少响应数据的大小

4.缓存响应内容，避免一些完全重复的请求

OkHttp基本使用

OkHttpClient：客户端对象Request：访问请求，Post请求中需要包含RequestBodyRequestBody：请求数据，在Post请求中用到Response：即网络请求的响应结果MediaType：数据类型，用来表明数据是jsonXHYIGBE，image，pdf等一系列格式client.newCall(request).execute()：同步的请求方法client.newCall(request).enqueue(Callback callBack)：异步的请求方法，但Callback是执行在子线程中的，因此不能在此进行UI更新操作

官网：http://square.github.io/okhttp/

添加依赖

com.squareup.okhttp3

okhttp

3.10.0

com.alibaba

fastjson

1.2.60

OkHttp工具类

package com.loginsimpl.utils;

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 headerMap;

private Map 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 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 (限流的,同一时间只允许一个访问,其他等待)

*/

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 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);

}

}

使用案例

发送get请求

String sync = OkHttpUtils.builder().url("http://localhost:9100/user/all")

.addHeader("token", "xxxxxxx")

.addParam("name", "xxx").addParam("pass", "xxx")

.get()

.sync();

System.out.println(sync);

发送Post请求

String sync = OkHttpUtils.builder().url("http://localhost:9100/user/all")

.addHeader("token", "xxxxxxx")

.addParam("name", "xxx").addParam("pass", "xxx")

.post(true) // true 为json提交方式

.sync();

System.out.println(sync);

发送异步请求

需要实现ICallBack接口

//回调实现类

public class AsyncHttpServiceImpl implements OkHttpUtils.ICallBack {

@Override

public void onSuccessful(Call call, String data) {

//接口正常返回的内容

System.out.println("onSuccessful"+data);

}

@Override

public void onFailure(Call call, String errorMsg) {

//接口错误返回的内容

System.out.println("onFailure"+errorMsg);

}

}

发送异步请求

OkHttpUtils.builder().url("http://localhost:9100/user/all")

.addHeader("token", "xxxxxxx")

.addParam("name", "xxx").addParam("pass", "xxx")

.post(true)

.async(new AsyncHttpServiceImpl());

版权声明：本文内容由网络用户投稿，版权归原作者所有，本站不拥有其著作权，亦不承担相应法律责任。如果您发现本站中有涉嫌抄袭或描述失实的内容，请联系我们jiasou666@gmail.com 处理，核实后本网站将在24小时内删除侵权内容。