java http库_java常见的 http 请求库比较

java常见的http请求库有httpclient，RestTemplate，OKhttp，更高层次封装的 feign、retrofit

1、HttpClient

HttpClient：代码复杂，还得操心资源回收等。代码很复杂，冗余代码多，不建议直接使用。

2、RestTemplate

RestTemplate： 是 Spring 提供的用于访问Rest服务的客户端， RestTemplate 提供了多种便捷访问远程Http服务的方法,能够大大提高客户端的编写效率。

引入jar包：

org.springframework.boot

spring-boot-starter-web

添加初始化配置(也可以不配，有默认的)--注意RestTemplate只有初始化配置，没有什么连接池

package com.itunion.config;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import org.springframework.http.client.ClientHttpRequestFactory;

import org.springframework.http.client.SimpleClientHttpRequestFactory;

import org.springframework.web.client.RestTemplate;

@Configuration

public class ApiConfig {

@Bean

public RestTemplate restTemplate(ClientHttpRequestFactory factory) {

return new RestTemplate(factory);

}

@Bean

public ClientHttpRequestFactory simpleClientHttpRequestFactory() {

SimpleClientHttpRequestFactory factory = new SimpleClientHttpRequestFactory();//默认的是JDK提供http连接，需要的话可以//通过setRequestFactory方法替换为例如Apache HttpComponents、Netty或//OkHttp等其它HTTP library。

factory.setReadTimeout(5000);//单位为ms

factory.setConnectTimeout(5000);//单位为ms

return factory;

}

}

(1)get请求(不带参的即把参数取消即可)

// 1-getForObject()

User user1 = this.restTemplate.getForObject(uri, User.class);

// 2-getForEntity()

ResponseEntity responseEntity1 = this.restTemplate.getForEntity(uri, User.class);

HttpStatus statusCode = responseEntity1.getStatusCode();

HttpHeaders header = responseEntity1.getHeaders();

User user2 = responseEntity1.getBody();

// 3-exchange()

RequestEntity requestEntity = RequestEntity.get(new URI(uri)).build();

ResponseEntity responseEntity2 = this.restTemplate.exchange(requestEntity, User.class);

User user3 = responseEntity2.getBody();

方式一：

Notice notice = restTemplate.getForObject("http://fantj.top/notice/list/{1}/{2}"

, Notice.class,1,5);

方式二：

Map map = new HashMap();

map.put("start","1");

map.put("page","5");

Notice notice = restTemplate.getForObject("http://fantj.top/notice/list/"

, Notice.class,map);

(2)post请求：

// 1-postForObject()

User user1 = this.restTemplate.postForObject(uri, user, User.class);

// 2-postForEntity()

ResponseEntity responseEntity1 = this.restTemplate.postForEntity(uri, user, User.class);

// 3-exchange()

RequestEntity requestEntity = RequestEntity.post(new URI(uri)).body(user);

ResponseEntity responseEntity2 = this.restTemplate.exchange(requestEntity, User.class);

方式一：

String url = "http://demo/api/book/";

HttpHeaders headers = new HttpHeaders();

MediaType type = MediaType.parseMediaType("application/json; charset=UTF-8");

headers.setContentType(type);

String requestJson = "{...}";

HttpEntity entity = new HttpEntity(requestJson,headers);

String result = restTemplate.postForObject(url, entity, String.class);

System.out.println(result);

方式二：

@Test

public void rtPostObject(){

RestTemplate restTemplate = new RestTemplate();

String url = "http://47.xxx.xxx.96/register/checkEmail";

HttpHeaders headers = new HttpHeaders();

headers.setContentType(MediaType.APPLICATION_FORM_URLENCODED);

MultiValueMap map= new LinkedMultiValueMap<>();

map.add("email", "[email protected]");

HttpEntity> request = new HttpEntity<>(map, headers);

ResponseEntity response = restTemplate.postForEntity( url, request , String.class );

System.out.println(response.getBody());

}

其它：还支持上传和下载功能；

3、okhttp

okhttp：OkHttp是一个高效的HTTP客户端，允许所有同一个主机地址的请求共享同一个socket连接；连接池减少请求延时；透明的GZIP压缩减少响应数据的大小；缓存响应内容，避免一些完全重复的请求

当网络出现问题的时候OkHttp依然坚守自己的职责，它会自动恢复一般的连接问题，如果你的服务有多个IP地址，当第一个IP请求失败时，OkHttp会交替尝试你配置的其他IP，OkHttp使用现代TLS技术(SNI, ALPN)初始化新的连接，当握手失败时会回退到TLS 1.0。

(1)使用：它的请求/响应 API 使用构造器模式builders来设计，它支持阻塞式的同步请求和带回调的异步请求。

引入jar包：

com.squareup.okhttp3

okhttp

3.10.0

(2)配置文件：

import okhttp3.ConnectionPool;

import okhttp3.OkHttpClient;

import org.springframework.context.annotation.Bean;

import org.springframework.context.annotation.Configuration;

import javax.net.ssl.SSLContext;

import javax.net.ssl.SSLSocketFactory;

import javax.net.ssl.TrustManager;

import javax.net.ssl.X509TrustManager;

import java.security.KeyManagementException;

import java.security.NoSuchAlgorithmException;

import java.security.SecureRandom;

import java.security.cert.CertificateException;

import java.security.cert.X509Certificate;

import java.util.concurrent.TimeUnit;

@Configuration

public class OkHttpConfiguration {

@Bean

public OkHttpClient okHttpClient() {

return new OkHttpClient.Builder()

//.sslSocketFactory(sslSocketFactory(), x509TrustManager())

.retryOnConnectionFailure(false)

.connectionPool(pool())

.connectTimeout(30, TimeUnit.SECONDS)

.readTimeout(30, TimeUnit.SECONDS)

.writeTimeout(30,TimeUnit.SECONDS)

.build();

}

@Bean

public X509TrustManager x509TrustManager() {

return new X509TrustManager() {

@Override

public void checkClientTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {

}

@Override

public void checkServerTrusted(X509Certificate[] x509Certificates, String s) throws CertificateException {

}

@Override

public X509Certificate[] getAcceptedIssuers() {

return new X509Certificate[0];

}

};

}

@Bean

public SSLSocketFactory sslSocketFactory() {

try {

//信任任何链接

SSLContext sslContext = SSLContext.getInstance("TLS");

sslContext.init(null, new TrustManager[]{x509TrustManager()}, new SecureRandom());

return sslContext.getSocketFactory();

} catch (NoSuchAlgorithmException e) {

e.printStackTrace();

} catch (KeyManagementException e) {

e.printStackTrace();

}

return null;

}

/**

* Create a new connection pool with tuning parameters appropriate for a single-user application.

* The tuning parameters in this pool are subject to change in future OkHttp releases. Currently

*/

@Bean

public ConnectionPool pool() {

return new ConnectionPool(200, 5, TimeUnit.MINUTES);

}

}

(3)util工具：

import okhttp3.*;

import org.apache.commons.lang3.exception.ExceptionUtils;

import org.slf4j.Logger;

import org.slf4j.LoggerFactory;

import java.io.File;

import java.util.Iterator;

import java.util.Map;

public class OkHttpUtil{

private static final Logger logger = LoggerFactory.getLogger(OkHttpUtil.class);

private static OkHttpClient okHttpClient;

@Autowired

public OkHttpUtil(OkHttpClient okHttpClient) {

OkHttpUtil.okHttpClient= okHttpClient;

}

/**

* get

* @param url 请求的url

* @param queries 请求的参数，在浏览器？后面的数据，没有可以传null

* @return

*/

public static String get(String url, Map queries) {

String responseBody = "";

StringBuffer sb = new StringBuffer(url);

if (queries != null && queries.keySet().size() > 0) {

boolean firstFlag = true;

Iterator iterator = queries.entrySet().iterator();

while (iterator.hasNext()) {

Map.Entry entry = (Map.Entry) iterator.next();

if (firstFlag) {

sb.append("?" + entry.getKey() + "=" + entry.getValue());

firstFlag = false;

} else {

sb.append("&" + entry.getKey() + "=" + entry.getValue());

}

}

}

Request request = new Request.Builder()

.url(sb.toString())

.build();

Response response = null;

try {

response = okHttpClient.newCall(request).execute();

int status = response.code();

if (response.isSuccessful()) {

return response.body().string();

}

} catch (Exception e) {

logger.error("okhttp3 put error >> ex = {}", ExceptionUtils.getStackTrace(e));

} finally {

if (response != null) {

response.close();

}

}

return responseBody;

}

/**

* post

*

* @param url 请求的url

* @param params post form 提交的参数

* @return

*/

public static String post(String url, Map params) {

String responseBody = "";

FormBody.Builder builder = new FormBody.Builder();

//添加参数

if (params != null && params.keySet().size() > 0) {

for (String key : params.keySet()) {

builder.add(key, params.get(key));

}

}

Request request = new Request.Builder()

.url(url)

.post(builder.build())

.build();

Response response = null;

try {

response = okHttpClient.newCall(request).execute();

int status = response.code();

if (response.isSuccessful()) {

return response.body().string();

}

} catch (Exception e) {

logger.error("okhttp3 post error >> ex = {}", ExceptionUtils.getStackTrace(e));

} finally {

if (response != null) {

response.close();

}

}

return responseBody;

}

/**

* get

* @param url 请求的url

* @param queries 请求的参数，在浏览器？后面的数据，没有可以传null

* @return

*/

public static String getForHeader(String url, Map queries) {

String responseBody = "";

StringBuffer sb = new StringBuffer(url);

if (queries != null && queries.keySet().size() > 0) {

boolean firstFlag = true;

Iterator iterator = queries.entrySet().iterator();

while (iterator.hasNext()) {

Map.Entry entry = (Map.Entry) iterator.next();

if (firstFlag) {

sb.append("?" + entry.getKey() + "=" + entry.getValue());

firstFlag = false;

} else {

sb.append("&" + entry.getKey() + "=" + entry.getValue());

}

}

}

Request request = new Request.Builder()

.addHeader("key", "value")

.url(sb.toString())

.build();

Response response = null;

try {

response = okHttpClient.newCall(request).execute();

int status = response.code();

if (response.isSuccessful()) {

return response.body().string();

}

} catch (Exception e) {

logger.error("okhttp3 put error >> ex = {}", ExceptionUtils.getStackTrace(e));

} finally {

if (response != null) {

response.close();

}

}

return responseBody;

}

/**

* Post请求发送JSON数据....{"name":"zhangsan","pwd":"123456"}

* 参数一：请求Url

* 参数二：请求的JSON

* 参数三：请求回调

*/

public static String postJsonParams(String url, String jsonParams) {

String responseBody = "";

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

Request request = new Request.Builder()

.url(url)

.post(requestBody)

.build();

Response response = null;

try {

response = okHttpClient.newCall(request).execute();

int status = response.code();

if (response.isSuccessful()) {

return response.body().string();

}

} catch (Exception e) {

logger.error("okhttp3 post error >> ex = {}", ExceptionUtils.getStackTrace(e));

} finally {

if (response != null) {

response.close();

}

}

return responseBody;

}

/**

* Post请求发送xml数据....

* 参数一：请求Url

* 参数二：请求的xmlString

* 参数三：请求回调

*/

public static String postXmlParams(String url, String xml) {

String responseBody = "";

RequestBody requestBody = RequestBody.create(MediaType.parse("application/xml; charset=utf-8"), xml);

Request request = new Request.Builder()

.url(url)

.post(requestBody)

.build();

Response response = null;

try {

response = okHttpClient.newCall(request).execute();

int status = response.code();

if (response.isSuccessful()) {

return response.body().string();

}

} catch (Exception e) {

logger.error("okhttp3 post error >> ex = {}", ExceptionUtils.getStackTrace(e));

} finally {

if (response != null) {

response.close();

}

}

return responseBody;

}

}