Java封装OkHttp3工具类，适用于Java后端开发者
说实在话，用过挺多网络请求工具，有过java原生的，HttpClient3和4，但是个人感觉用了OkHttp3之后，之前的那些完全不想再用了。怎么说呢，代码轻便，使用起来很很很灵活，响应快，比起HttpClient好用许多。当然，这些是我个人观点，不喜勿喷。
准备工作
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>
引入json是因为工具类中有些地方用到了，现在通信都流行使用json传输，也少不了要这个jar包
工具类代码
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);
}
}
使用教程
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
}
});
}结语
封装的明明白白，使用的简简单单，简单的几下就能做请求，用建造者模式是真的舒服。
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