httpclient详解
首先 什么是httpclient?
HttpClient 是Apache Jakarta Common 下的子项目,可以用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包,并且它支持 HTTP 协议最新的版本和建议。
简介
HTTP 协议可能是现在 Internet 上使用得最多、最重要的协议了,越来越多的 Java 应用程序需要直接通过 HTTP 协议来访问网络资源。虽然在 JDK 的 java net包中已经提供了访问 HTTP 协议的基本功能,但是对于大部分应用程序来说,JDK 库本身提供的功能还不够丰富和灵活。HttpClient 是 Apache Jakarta Common 下的子项目,用来提供高效的、最新的、功能丰富的支持 HTTP 协议的客户端编程工具包,并且它支持 HTTP 协议最新的版本和建议。HttpClient 已经应用在很多的项目中,比如 Apache Jakarta 上很著名的另外两个开源项目 Cactus 和 HTMLUnit 都使用了 HttpClient。------------来源百度百科
功能介绍
以下列出的是 HttpClient 提供的主要的功能,要知道更多详细的功能可以参见 HttpClient 的主页。
(1)实现了所有 HTTP 的方法(GET,POST,PUT,HEAD 等)
(2)支持自动转向
(3)支持 HTTPS 协议
(4)支持代理服务器等
------------ 来源于百度百科
使用 HttpClient 需要以下 6 个步骤:
1. 创建HttpClient对象。
2. 创建请求方法的实例,并指定请求URL。如果需要发送GET请求,创建HttpGet对象;如果需要发送POST请求,创建HttpPost对象。
扫描二维码关注公众号,回复: 8589650 查看本文章3. 如果需要发送请求参数,可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数;对于HttpPost对象而言,也可调用setEntity(HttpEntity entity)方法来设置请求参数。
4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求,该方法返回一个HttpResponse。
5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头;调用HttpResponse的getEntity()方法可获取HttpEntity对象,该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。
6. 释放连接。无论执行方法是否成功,都必须释放连接。
优点
- HttpClient: 可以进行远端测试,需要进行网络传输。
- 封装实现了所有HTTP的方法,如GET,POST,PUT,HEAD,
- 支持redirect,会话保持,
- 支持文件上传。
例子(Springboot+RestFul风格接口API)
1.导入maven依赖
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5</version>
</dependency>
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpcore</artifactId>
<version>4.4.4</version>
</dependency>
2.测试代码
// 1. 创建HttpClient对象。
CloseableHttpClient httpClient = HttpClients.createDefault();
// 2. 创建请求方法的实例,并指定请求URL。如果需要发送GET请求,创建HttpGet对象;如果需要发送POST请求,创建HttpPost对象。
URIBuilder uriBuilder = new URIBuilder("http://127.0.0.1:8080/students/null");
//GET请求,创建HttpGet对象;
HttpGet httpGet = new HttpGet(uriBuilder.build());
//3. 如果需要发送请求参数,可调用HttpGet、HttpPost共同的setParams(HetpParams params)方法来添加请求参数;
//对于HttpPost对象而言,也可调用setEntity(HttpEntity entity)方法来设置请求参数。没有可以省略
// 响应模型
CloseableHttpResponse response = null;
try {
// 4. 调用HttpClient对象的execute(HttpUriRequest request)发送请求,该方法返回一个HttpResponse。
response = httpClient.execute(httpGet);
// 5. 调用HttpResponse的getAllHeaders()、getHeaders(String name)等方法可获取服务器的响应头;
//调用HttpResponse的getEntity()方法可获取HttpEntity对象,该对象包装了服务器的响应内容。程序可通过该对象获取服务器的响应内容。
HttpEntity responseEntity = response.getEntity();
System.out.println("响应状态:" + response.getStatusLine());
if (responseEntity != null) {
System.out.println("响应内容长度:" + responseEntity.getContentLength());
System.out.println("响应内容:" + EntityUtils.toString(responseEntity));
}
} catch (ClientProtocolException e) {
e.printStackTrace();
} catch (ParseException e) {
e.printStackTrace();
} catch (IOException e) {
e.printStackTrace();
} finally {
try {
// 6. 释放连接。无论执行方法是否成功,都必须释放连接。
if (httpClient != null) {
httpClient.close();
}
if (response != null) {
response.close();
}
} catch (IOException e) {
e.printStackTrace();
}
}
运行截图
其他请求类似:
我封装了httpClient工具类,有需要可以拿去。
httpClient工具类
package com.inventec.studentManagement.utils;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.Iterator;
import java.util.List;
import java.util.Map;
import java.util.Map.Entry;
import java.util.Set;
import org.apache.http.Header;
import org.apache.http.HttpStatus;
import org.apache.http.NameValuePair;
import org.apache.http.client.config.RequestConfig;
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpDelete;
import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.client.methods.HttpPatch;
import org.apache.http.client.methods.HttpPost;
import org.apache.http.client.methods.HttpPut;
import org.apache.http.client.methods.HttpRequestBase;
import org.apache.http.client.utils.URIBuilder;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.params.CoreConnectionPNames;
import org.apache.http.util.EntityUtils;
import com.alibaba.fastjson.JSONObject;
import com.inventec.studentManagement.pojo.HttpClientResult;
/**
* Description: httpClient工具类
*
*/
public class HttpClientUtils {
// 编码格式。发送编码格式统一用UTF-8
private static final String ENCODING = "UTF-8";
// 设置连接超时时间,单位毫秒。
private static final int CONNECT_TIMEOUT = 6000;
// 请求获取数据的超时时间(即响应时间),单位毫秒。
private static final int SOCKET_TIMEOUT = 60000;
/**
* 发送get请求;不带请求头和请求参数
*
* @param url 请求地址
* @return
* @throws Exception
*/
public static HttpClientResult doGet(String url) throws Exception {
return doGet(url, null, null);
}
/**
* 发送get请求;带请求参数
*
* @param url 请求地址
* @param params 请求参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doGet(String url, Map<String, String> params) throws Exception {
return doGet(url, null, params);
}
/**
* 发送get请求;带请求头和请求参数
*
* @param url 请求地址
* @param headers 请求头集合
* @param params 请求参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doGet(String url, Map<String, String> headers, Map<String, String> params) throws Exception {
// 创建httpClient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
// 创建访问的地址
URIBuilder uriBuilder = new URIBuilder(url);
if (params != null) {
Set<Entry<String, String>> entrySet = params.entrySet();
for (Entry<String, String> entry : entrySet) {
uriBuilder.setParameter(entry.getKey(), entry.getValue());
}
}
// 创建http对象
HttpGet httpGet = new HttpGet(uriBuilder.build());
/**
* setConnectTimeout:设置连接超时时间,单位毫秒。
* setConnectionRequestTimeout:设置从connect Manager(连接池)获取Connection
* 超时时间,单位毫秒。这个属性是新加的属性,因为目前版本是可以共享连接池的。
* setSocketTimeout:请求获取数据的超时时间(即响应时间),单位毫秒。 如果访问一个接口,多少时间内无法返回数据,就直接放弃此次调用。
*/
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
httpGet.setConfig(requestConfig);
// 设置请求头
httpGet.addHeader("content-type", "application/json");
httpGet.addHeader("Accept", "application/json");
httpGet.addHeader("ApiVersion", "v2");
// 创建httpResponse对象
CloseableHttpResponse httpResponse = null;
try {
// 执行请求并获得响应结果
return getHttpClientResult(httpResponse, httpClient, httpGet);
} finally {
// 释放资源
release(httpResponse, httpClient);
}
}
/**
* 发送post请求;不带请求头和请求参数
*
* @param url 请求地址
* @return
* @throws Exception
*/
public static HttpClientResult doPost(String url) throws Exception {
return doPost(url, null, null);
}
/**
* 发送post请求;带请求参数
*
* @param url 请求地址
* @param params 参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doPost(String url, JSONObject params) throws Exception {
return doPost(url, null, params);
}
/**
* 发送post请求;带请求头和请求参数
*
* @param url 请求地址
* @param headers 请求头集合
* @param params 请求参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doPost(String url, Map<String, String> headers, JSONObject params) throws Exception {
// 创建httpClient对象
CloseableHttpClient httpClient = HttpClients.createDefault();
// 创建http对象
HttpPost httpPost = new HttpPost(url);
/**
* setConnectTimeout:设置连接超时时间,单位毫秒。
* setConnectionRequestTimeout:设置从connect Manager(连接池)获取Connection
* 超时时间,单位毫秒。这个属性是新加的属性,因为目前版本是可以共享连接池的。
* setSocketTimeout:请求获取数据的超时时间(即响应时间),单位毫秒。 如果访问一个接口,多少时间内无法返回数据,就直接放弃此次调用。
*/
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
httpPost.setConfig(requestConfig);
// 设置请求头
/*httpPost.setHeader("Cookie", "");
httpPost.setHeader("Connection", "keep-alive");
httpPost.setHeader("Accept", "application/json");
httpPost.setHeader("Accept-Language", "zh-CN,zh;q=0.9");
httpPost.setHeader("Accept-Encoding", "gzip, deflate, br");
httpPost.setHeader("User-Agent", "Mozilla/5.0 (Windows NT 10.0; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/65.0.3325.181 Safari/537.36");*/
httpPost.setHeader("Accept", "application/json");
httpPost.addHeader("Content-type","application/json; charset=utf-8");
httpPost.addHeader("ApiVersion", "v2");
packageHeader(headers, httpPost);
// 封装请求参数
packageParam(params, httpPost);
// 创建httpResponse对象
CloseableHttpResponse httpResponse = null;
try {
// 执行请求并获得响应结果
return getHttpClientResult(httpResponse, httpClient, httpPost);
} finally {
// 释放资源
release(httpResponse, httpClient);
}
}
/**
* 发送put请求;不带请求参数
*
* @param url 请求地址
* @param params 参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doPut(String url) throws Exception {
return doPut(url,null);
}
/**
* 发送put请求;带请求参数
*
* @param url 请求地址
* @param params 参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doPut(String url,JSONObject params) throws Exception {
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPut httpPut = new HttpPut(url);
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
httpPut.setConfig(requestConfig);
httpPut.addHeader("ApiVersion", "v2");
packageParam(params, httpPut);
CloseableHttpResponse httpResponse = null;
try {
return getHttpClientResult(httpResponse, httpClient, httpPut);
} finally {
release(httpResponse, httpClient);
}
}
/**
* 发送patch请求;不带请求参数
*
* @param url 请求地址
* @param params 参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doPatch(String url) throws Exception {
return doPatch(url,null);
}
/**
* 发送patch请求;带请求参数
*
* @param url 请求地址
* @param params 参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doPatch(String url,JSONObject params) throws Exception {
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpPatch httpPatch = new HttpPatch(url);
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
httpPatch.setConfig(requestConfig);
httpPatch.setHeader("Accept", "application/json");
httpPatch.addHeader("Content-type","application/json; charset=utf-8");
httpPatch.addHeader("ApiVersion", "v2");
packageParam(params, httpPatch);
CloseableHttpResponse httpResponse = null;
try {
return getHttpClientResult(httpResponse, httpClient, httpPatch);
} finally {
release(httpResponse, httpClient);
}
}
/**
* 发送delete请求;不带请求参数
*
* @param url 请求地址
* @param params 参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doDelete(String url) throws Exception {
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpDelete httpDelete = new HttpDelete(url);
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
httpDelete.addHeader("ApiVersion", "v2");
httpDelete.setConfig(requestConfig);
CloseableHttpResponse httpResponse = null;
try {
return getHttpClientResult(httpResponse, httpClient, httpDelete);
} finally {
release(httpResponse, httpClient);
}
}
/**
* 发送delete请求;带请求参数
*
* @param url 请求地址
* @param params 参数集合
* @return
* @throws Exception
*/
public static HttpClientResult doDelete(String url,JSONObject params) throws Exception {
/*if (params == null) {
params = new JSONObject();
}
params.put("_method", "delete");
return doPost(url, params);
*/
CloseableHttpClient httpClient = HttpClients.createDefault();
HttpDeleteWithBody httpDelete = new HttpDeleteWithBody(url);
RequestConfig requestConfig = RequestConfig.custom().setConnectTimeout(CONNECT_TIMEOUT).setSocketTimeout(SOCKET_TIMEOUT).build();
httpDelete.addHeader("ApiVersion", "v2");
httpDelete.setHeader("Accept", "application/json");
httpDelete.addHeader("Content-type","application/json; charset=utf-8");
httpDelete.setConfig(requestConfig);
httpDelete.setEntity(new StringEntity(params.toJSONString()));
httpDelete.getParams().setParameter(CoreConnectionPNames.SO_TIMEOUT, 20000);
packageParam(params, httpDelete);
CloseableHttpResponse httpResponse = null;
try {
return getHttpClientResult(httpResponse, httpClient, httpDelete);
} finally {
release(httpResponse, httpClient);
}
}
/**
* Description: 封装请求头
* @param params
* @param httpMethod
*/
public static void packageHeader(Map<String, String> params, HttpRequestBase httpMethod) {
// 封装请求头
if (params != null) {
Set<Entry<String, String>> entrySet = params.entrySet();
for (Entry<String, String> entry : entrySet) {
// 设置到请求头到HttpRequestBase对象中
httpMethod.setHeader(entry.getKey(), entry.getValue());
}
}
}
/**
* Description: 封装请求参数
*
* @param params
* @param httpMethod
* @throws UnsupportedEncodingException
*/
public static void packageParam(JSONObject params, HttpEntityEnclosingRequestBase httpMethod)
throws UnsupportedEncodingException {
// 封装请求参数
/*if (params != null) {
List<NameValuePair> nvps = new ArrayList<NameValuePair>();
Set<Entry<String, String>> entrySet = params.entrySet();
for (Entry<String, String> entry : entrySet) {
nvps.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
}
// 设置到请求的http对象中
httpMethod.setEntity(new UrlEncodedFormEntity(nvps, ENCODING));
}*/
StringEntity entity = new StringEntity(params.toString(),"UTF-8");
httpMethod.setEntity(entity);
}
/**
* Description: 获得响应结果
*
* @param httpResponse
* @param httpClient
* @param httpMethod
* @return
* @throws Exception
*/
public static HttpClientResult getHttpClientResult(CloseableHttpResponse httpResponse,
CloseableHttpClient httpClient, HttpRequestBase httpMethod) throws Exception {
// 执行请求
httpResponse = httpClient.execute(httpMethod);
// 获取返回结果
if (httpResponse != null && httpResponse.getStatusLine() != null) {
String content = "";
String header = "";
if (httpResponse.getEntity() != null) {
content = EntityUtils.toString(httpResponse.getEntity(), ENCODING);
Header[] allHeaders = httpResponse.getAllHeaders();
for (Header header2 : allHeaders) {
if ("ApiVersion".equals(header2.getName())) {
header=header2.getName()+":"+header2.getValue();
}
}
}
return new HttpClientResult(httpResponse.getStatusLine().getStatusCode(), content,header);
}
return new HttpClientResult(HttpStatus.SC_INTERNAL_SERVER_ERROR);
}
/**
* Description: 释放资源
*
* @param httpResponse
* @param httpClient
* @throws IOException
*/
public static void release(CloseableHttpResponse httpResponse, CloseableHttpClient httpClient) throws IOException {
// 释放资源
if (httpResponse != null) {
httpResponse.close();
}
if (httpClient != null) {
httpClient.close();
}
}
}
封装httpClient响应结果
package com.inventec.studentManagement.pojo;
import java.io.Serializable;
/**
* Description: 封装httpClient响应结果
*
*/
public class HttpClientResult implements Serializable {
private static final long serialVersionUID = 2168152194164783950L;
/**
* 响应状态码
*/
private int code;
/**
* 响应请求头
*/
/**
* 响应数据
*/
private String content;
public HttpClientResult() {
}
public HttpClientResult(int code) {
this.code = code;
}
public HttpClientResult(String content) {
this.content = content;
}
public HttpClientResult(int code, String content) {
this.code = code;
this.content = content;
}
public int getCode() {
return code;
}
public void setCode(int code) {
this.code = code;
}
public String getContent() {
return content;
}
public void setContent(String content) {
this.content = content;
}
private String header;
public String getHeader() {
return header;
}
public void setHeader(String header) {
this.header = header;
}
@Override
public String toString() {
return "HttpClientResult [code=" + code + ", content=" + content + ", header=" + header + "]";
}
public HttpClientResult(int code, String content, String header) {
super();
this.code = code;
this.content = content;
this.header = header;
}
/*@Override
public String toString() {
return "HttpClientResult [code=" + code + ", content=" + content + "]";
}
*/
}
HttpPost、HttpPut继承了HttpEntityEnclosingRequestBase类,所以有setEntity方法。详情请自行查看源码。
而HttpDelete没有对应的setEntity()方法,那么怎么传递呢?
定义一个类如继承HttpEntityEnclosingRequestBase类
package com.inventec.studentManagement.utils;
import org.apache.http.client.methods.HttpEntityEnclosingRequestBase;
import java.net.URI;
import org.apache.http.annotation.NotThreadSafe;
@NotThreadSafe
class HttpDeleteWithBody extends HttpEntityEnclosingRequestBase {
public static final String METHOD_NAME = "DELETE";
public String getMethod() { return METHOD_NAME; }
public HttpDeleteWithBody(final String uri) {
super();
setURI(URI.create(uri));
}
public HttpDeleteWithBody(final URI uri) {
super();
setURI(uri);
}
public HttpDeleteWithBody() { super(); }
}
以上是工具类的代码,有需要自行复制。
举一个post请求带json参数的例子
JSONObject jsonObj = new JSONObject();
jsonObj.put("student_sno", "aaaaaaaaaaaaaaa");
jsonObj.put("student_sname", "aaaaa");
jsonObj.put("student_sex", "1");
jsonObj.put("student_age", "12");
jsonObj.put("student_time", "2019-12-09 12:45:11");
HttpClientResult result = HttpClientUtils.doPost("http://localhost:8080/students/", jsonObj);
System.out.println("result===" + result);
assertTrue(contentString.equals(result.toString()));
其他类似,我相信大家都能看懂!
httpclient 一般用于远端(服务器端)测试
如果直接想在本地测试,请点击:https://blog.csdn.net/huzecom/article/details/103694319