Java中的httpclient4.5应该怎么使用

一、所需要的jar包

httpclient-4.5.jar

httpcore-4.4.1.jar

httpmime-4.5.jar

二、实例

Java代码

package cn.tzz.apache.httpclient

import java.io.File

import java.io.IOException

import java.net.URL

import java.util.ArrayList

import java.util.List

import java.util.Map

import org.apache.http.HttpEntity

import org.apache.http.NameValuePair

import org.apache.http.client.config.RequestConfig

import org.apache.http.client.entity.UrlEncodedFormEntity

import org.apache.http.client.methods.CloseableHttpResponse

import org.apache.http.client.methods.HttpGet

import org.apache.http.client.methods.HttpPost

import org.apache.http.conn.ssl.DefaultHostnameVerifier

import org.apache.http.conn.util.PublicSuffixMatcher

import org.apache.http.conn.util.PublicSuffixMatcherLoader

import org.apache.http.entity.ContentType

import org.apache.http.entity.StringEntity

import org.apache.http.entity.mime.MultipartEntityBuilder

import org.apache.http.entity.mime.content.FileBody

import org.apache.http.entity.mime.content.StringBody

import org.apache.http.impl.client.CloseableHttpClient

import org.apache.http.impl.client.HttpClients

import org.apache.http.message.BasicNameValuePair

import org.apache.http.util.EntityUtils

public class HttpClientUtil {

private RequestConfig requestConfig = RequestConfig.custom()

.setSocketTimeout(15000)

.setConnectTimeout(15000)

.setConnectionRequestTimeout(15000)

.build()

private static HttpClientUtil instance = null

private HttpClientUtil(){}

public static HttpClientUtil getInstance(){

if (instance == null) {

instance = new HttpClientUtil()

}

return instance

}

/**

* 发送 post请求

* @param httpUrl 地址

*/

public String sendHttpPost(String httpUrl) {

HttpPost httpPost = new HttpPost(httpUrl)// 创建httpPost

return sendHttpPost(httpPost)

}

/**

* 发送 post请求

* @param httpUrl 地址

* @param params 参数(格式:key1=value1&key2=value2)

*/

public String sendHttpPost(String httpUrl, String params) {

HttpPost httpPost = new HttpPost(httpUrl)// 创建httpPost

try {

//设置参数

StringEntity stringEntity = new StringEntity(params, "UTF-8")

stringEntity.setContentType("application/x-www-form-urlencoded")

httpPost.setEntity(stringEntity)

} catch (Exception e) {

e.printStackTrace()

}

return sendHttpPost(httpPost)

}

/**

* 发送 post请求

* @param httpUrl 地址

* @param maps 参数

*/

public String sendHttpPost(String httpUrl, Map<String, String>maps) {

HttpPost httpPost = new HttpPost(httpUrl)// 创建httpPost

// 创建参数队列

List<NameValuePair>nameValuePairs = new ArrayList<NameValuePair>()

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

nameValuePairs.add(new BasicNameValuePair(key, maps.get(key)))

}

try {

httpPost.setEntity(new UrlEncodedFormEntity(nameValuePairs, "UTF-8"))

} catch (Exception e) {

e.printStackTrace()

}

return sendHttpPost(httpPost)

}

/**

* 发送 post请求（带文件）

* @param httpUrl 地址

* @param maps 参数

* @param fileLists 附件

*/

public String sendHttpPost(String httpUrl, Map<String, String>maps, List<File>fileLists) {

HttpPost httpPost = new HttpPost(httpUrl)// 创建httpPost

MultipartEntityBuilder meBuilder = MultipartEntityBuilder.create()

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

meBuilder.addPart(key, new StringBody(maps.get(key), ContentType.TEXT_PLAIN))

}

for(File file : fileLists) {

FileBody fileBody = new FileBody(file)

meBuilder.addPart("files", fileBody)

}

HttpEntity reqEntity = meBuilder.build()

httpPost.setEntity(reqEntity)

return sendHttpPost(httpPost)

}

/**

* 发送Post请求

* @param httpPost

* @return

*/

private String sendHttpPost(HttpPost httpPost) {

CloseableHttpClient httpClient = null

CloseableHttpResponse response = null

HttpEntity entity = null

String responseContent = null

try {

// 创建默认的httpClient实例.

httpClient = HttpClients.createDefault()

httpPost.setConfig(requestConfig)

// 执行请求

response = httpClient.execute(httpPost)

entity = response.getEntity()

responseContent = EntityUtils.toString(entity, "UTF-8")

} catch (Exception e) {

e.printStackTrace()

} finally {

try {

// 关闭连接,释放资源

if (response != null) {

response.close()

}

if (httpClient != null) {

httpClient.close()

}

} catch (IOException e) {

e.printStackTrace()

}

}

return responseContent

}

/**

* 发送 get请求

* @param httpUrl

*/

public String sendHttpGet(String httpUrl) {

HttpGet httpGet = new HttpGet(httpUrl)// 创建get请求

return sendHttpGet(httpGet)

}

/**

* 发送 get请求Https

* @param httpUrl

*/

public String sendHttpsGet(String httpUrl) {

HttpGet httpGet = new HttpGet(httpUrl)// 创建get请求

return sendHttpsGet(httpGet)

}

/**

* 发送Get请求

* @param httpPost

* @return

*/

private String sendHttpGet(HttpGet httpGet) {

CloseableHttpClient httpClient = null

CloseableHttpResponse response = null

HttpEntity entity = null

String responseContent = null

try {

// 创建默认的httpClient实例.

httpClient = HttpClients.createDefault()

httpGet.setConfig(requestConfig)

// 执行请求

response = httpClient.execute(httpGet)

entity = response.getEntity()

responseContent = EntityUtils.toString(entity, "UTF-8")

} catch (Exception e) {

e.printStackTrace()

} finally {

try {

// 关闭连接,释放资源

if (response != null) {

response.close()

}

if (httpClient != null) {

httpClient.close()

}

} catch (IOException e) {

e.printStackTrace()

}

}

return responseContent

}

/**

* 发送Get请求Https

* @param httpPost

* @return

*/

private String sendHttpsGet(HttpGet httpGet) {

CloseableHttpClient httpClient = null

CloseableHttpResponse response = null

HttpEntity entity = null

String responseContent = null

try {

// 创建默认的httpClient实例.

PublicSuffixMatcher publicSuffixMatcher = PublicSuffixMatcherLoader.load(new URL(httpGet.getURI().toString()))

DefaultHostnameVerifier hostnameVerifier = new DefaultHostnameVerifier(publicSuffixMatcher)

httpClient = HttpClients.custom().setSSLHostnameVerifier(hostnameVerifier).build()

httpGet.setConfig(requestConfig)

// 执行请求

response = httpClient.execute(httpGet)

entity = response.getEntity()

responseContent = EntityUtils.toString(entity, "UTF-8")

} catch (Exception e) {

e.printStackTrace()

} finally {

try {

// 关闭连接,释放资源

if (response != null) {

response.close()

}

if (httpClient != null) {

httpClient.close()

}

} catch (IOException e) {

e.printStackTrace()

}

}

return responseContent

}

}

代码如下：

package org.apache.http.examples.client

import java.net.URI

import java.util.List

import org.apache.http.HttpEntity

import org.apache.http.client.methods.CloseableHttpResponse

import org.apache.http.client.methods.HttpGet

import org.apache.http.client.methods.HttpUriRequest

import org.apache.http.client.methods.RequestBuilder

import org.apache.http.cookie.Cookie

import org.apache.http.impl.client.BasicCookieStore

import org.apache.http.impl.client.CloseableHttpClient

import org.apache.http.impl.client.HttpClients

import org.apache.http.util.EntityUtils

/**

* A example that demonstrates how HttpClient APIs can be used to perform

* form-based logon.

*/

public class ClientFormLogin { public static void main(String[] args) throws Exception {       BasicCookieStore cookieStore = new BasicCookieStore()

CloseableHttpClient httpclient = HttpClients.custom()

.setDefaultCookieStore(cookieStore)

.build()

try {

HttpGet httpget = new HttpGet("https://someportal/")

CloseableHttpResponse response1 = httpclient.execute(httpget)

try {HttpEntity entity = response1.getEntity()

System.out.println("Login form get: " + response1.getStatusLine())

EntityUtils.consume(entity)

System.out.println("Initial set of cookies:")

List<Cookie>cookies = cookieStore.getCookies()

if (cookies.isEmpty()) {System.out.println("None")} else {for (int i = 0i <cookies.size()i++) { System.out.println("- " + cookies.get(i).toString()) }}           } finally {response1.close()}

HttpUriRequest login = RequestBuilder.post()

.setUri(new URI("https://someportal/"))

.addParameter("IDToken1", "username")

addParameter("IDToken2", "password")

.build()CloseableHttpResponse response2 = httpclient.execute(login)

try {HttpEntity entity = response2.getEntity()

System.out.println("Login form get: " + response2.getStatusLine()) EntityUtils.consume(entity)

System.out.println("Post logon cookies:")

List<Cookie>cookies = cookieStore.getCookies() for (int i = 0i <cookies.size()

i++) {}finally { response2.close()

finally}

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定义一个简单的restful接口 @RestController public class TestController { @RequestMapping(value = "testPost", method = RequestMethod.POST) public ResponseBean testPost(@RequestBody RequestBean requestBean) { ResponseBean responseBean = new ResponseBean()responseBean.setRetCode("0000")responseBean.setRetMsg("succ")return responseBean} } 使用RestTemplate访问该服务 //请求地址 String url = ""//入参 RequestBean requestBean = new RequestBean()requestBean.setTest1("1")requestBean.setTest2("2")requestBean.setTest3("3")RestTemplate restTemplate = new RestTemplate()ResponseBean responseBean = restTemplate.postForObject(url, requestBean, ResponseBean.class)从这个例子可以看出，使用restTemplate访问restful接口非常的简单粗暴无脑。(url, requestMap, ResponseBean.class)这三个参数分别代表 请求地址、请求参数、HTTP响应转换被转换成的对象类型。 RestTemplate方法的名称遵循命名约定，第一部分指出正在调用什么HTTP方法，第二部分指示返回的内容。本例中调用了restTemplate.postForObject方法，post指调用了HTTP的post方法，Object指将HTTP响应转换为您选择的对象类型。还有其他很多类似的方法，有兴趣的同学可以参考官方api。 三.手动指定转换器(HttpMessageConverter) 我们知道，调用reseful接口传递的数据内容是json格式的字符串，返回的响应也是json格式的字符串。然而restTemplate.postForObject方法的请求参数RequestBean和返回参数ResponseBean却都是java类。是RestTemplate通过HttpMessageConverter自动帮我们做了转换的 *** 作。 默认情况下RestTemplate自动帮我们注册了一组HttpMessageConverter用来处理一些不同的contentType的请求。 如StringHttpMessageConverter来处理text/plainMappingJackson2HttpMessageConverter来处理application/jsonMappingJackson2XmlHttpMessageConverter来处理application/xml。 你可以在org.springframework.http.converter包下找到所有spring帮我们实现好的转换器。 如果现有的转换器不能满足你的需求，你还可以实现org.springframework.http.converter.HttpMessageConverter接口自己写一个。详情参考官方api。 选好了HttpMessageConverter后怎么把它注册到我们的RestTemplate中呢。 RestTemplate restTemplate = new RestTemplate()//获取RestTemplate默认配置好的所有转换器 List<HttpMessageConverter<?>>messageConverters = restTemplate.getMessageConverters()//默认的MappingJackson2HttpMessageConverter在第7个 先把它移除掉 messageConverters.remove(6)//添加上GSON的转换器 messageConverters.add(6, new GsonHttpMessageConverter())这个简单的例子展示了如何使用GsonHttpMessageConverter替换掉默认用来处理application/json的MappingJackson2HttpMessageConverter。 四.设置底层连接方式 要创建一个RestTemplate的实例，您可以像上述例子中简单地调用默认的无参数构造函数。这将使用java.NET包中的标准Java类作为底层实现来创建HTTP请求。 但很多时候我们需要像传统的HttpClient那样设置HTTP请求的一些属性。RestTemplate使用了一种很偷懒的方式实现了这个需求，那就是直接使用一个HttpClient作为底层实现...... //生成一个设置了连接超时时间、请求超时时间、异常最大重试次数的httpClient RequestConfig config = RequestConfig.custom().setConnectionRequestTimeout(10000).setConnectTimeout(10000).setSocketTimeout(30000).build()HttpClientBuilder builder = HttpClientBuilder.create().setDefaultRequestConfig(config).setRetryHandler(new DefaultHttpRequestRetryHandler(5, false))HttpClient httpClient = builder.build()//使用httpClient创建一个ClientHttpRequestFactory的实现 ClientHttpRequestFactory requestFactory = new HttpComponentsClientHttpRequestFactory(httpClient)//ClientHttpRequestFactory作为参数构造一个使用作为底层的RestTemplate RestTemplate restTemplate = new RestTemplate(requestFactory)五.设置拦截器(ClientHttpRequestInterceptor) 有时候我们需要对请求做一些通用的拦截设置，这就可以使用拦截器进行处理。拦截器需要我们实现org.springframework.http.client.ClientHttpRequestInterceptor接口自己写。 举个简单的例子，写一个在header中根据请求内容和地址添加令牌的拦截器。 public class TokenInterceptor implements ClientHttpRequestInterceptor { @Override public ClientHttpResponse intercept(HttpRequest request, byte[] body, ClientHttpRequestExecution execution) throws IOException { //请求地址 String checkTokenUrl = request.getURI().getPath()//token有效时间 int ttTime = (int) (System.currentTimeMillis() / 1000 + 1800)//请求方法名 POST、GET等 String methodName = request.getMethod().name()//请求内容 String requestBody = new String(body)//生成令牌 此处调用一个自己写的方法，有兴趣的朋友可以自行google如何使用ak/sk生成token，此方法跟本教程无关，就不贴出来了 String token = TokenHelper.generateToken(checkTokenUrl, ttTime, methodName, requestBody)//将令牌放入请求header中 request.getHeaders().add("X-Auth-Token",token)return execution.execute(request, body)} } 创建RestTemplate实例的时候可以这样向其中添加拦截器 RestTemplate restTemplate = new RestTemplate()//向restTemplate中添加自定义的拦截器 restTemplate.getInterceptors().add(new TokenInterceptor())

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