java发起http请求
使用HttpClient发送请求的一般步骤如下:
(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。
(3) 如果需要发送请求参数,可调用HttpGet对象的setParams(HetpParams params)方法来添加请求参数;对于HttpPost对象而言,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。
有两种依赖包,commons和apache依赖包,选择其中一种即可。以下是混用的,仅做参考即可。
引入工具依赖包如下:
<!-- commons-httpclient http请求工具依赖包 -->
<dependency>
<groupId>commons-httpclient</groupId>
<artifactId>commons-httpclient</artifactId>
<version>3.1</version>
</dependency>
<!-- apache http请求工具依赖包 -->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.3.6</version>
</dependency>
方法如下所示:
import lombok.extern.slf4j.Slf4j;
import org.apache.commons.httpclient.HttpClient;
import org.apache.commons.httpclient.methods.PostMethod;
import org.apache.commons.httpclient.params.HttpMethodParams;
import org.apache.commons.lang.ArrayUtils;
import org.apache.http.HttpEntity;
import org.apache.http.HttpResponse;
import org.apache.http.HttpStatus;
import org.apache.commons.httpclient.NameValuePair;
import org.apache.http.client.config.RequestConfig;
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.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.util.EntityUtils;
import java.io.IOException;
import java.util.*;
@Slf4j
public class HttpClientTest {
/**
* 发起post请求 没有任何body参数的情况
*
* @param url 请求的目标url地址
* @param data 请求数据
* @return 将响应结果转换成string返回
* @throws IOException 可能出现的异常
*/
private static String postMsg(String url, String data) throws IOException {
// 根据url地址发起post请求
HttpPost httppost = new HttpPost(url);
StringEntity stEntity;
// 获取到httpclient客户端
CloseableHttpClient httpclient = HttpClients.createDefault();
try {
// 设置请求的一些头部信息
httppost.addHeader("Content-Type", "application/json");
httppost.addHeader("procode", "test");
stEntity = new StringEntity(data, "UTF-8");
httppost.setEntity(stEntity);
// 设置请求的一些配置设置,主要设置请求超时,连接超时等参数
RequestConfig requestConfig = RequestConfig.custom()
.setConnectTimeout(5000).setConnectionRequestTimeout(1000).setSocketTimeout(5000)
.build();
httppost.setConfig(requestConfig);
// 执行请求
CloseableHttpResponse response = httpclient.execute(httppost);
// 请求结果
String resultString = "";
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
log.info("请求状态:{}", response.getStatusLine().getStatusCode());
// 获取请求响应结果
HttpEntity entity = response.getEntity();
if (entity != null) {
// 将响应内容转换为指定编码的字符串
resultString = EntityUtils.toString(entity, "UTF-8");
log.info("Response content:{}", resultString);
return resultString;
}
} else {
log.info("请求失败!");
return resultString;
}
} catch (Exception e) {
throw e;
} finally {
httpclient.close();
}
return null;
}
/**
* body有内容的post请求方法 controller可以用bean直接接收参数
*
* @param url 目标地址
* @param params 封装的参数
* @param codePage 字符编码
* @return 将响应结果转换成string返回
* @throws Exception 可能出现的异常
*/
private synchronized static String postData(String url, Map<String, String> params, String codePage) throws Exception {
HttpClient httpClient = new HttpClient();
// 请求相关超时时间设置
httpClient.getHttpConnectionManager().getParams().setConnectionTimeout(10 * 1000);
httpClient.getHttpConnectionManager().getParams().setSoTimeout(10 * 1000);
PostMethod method = new PostMethod(url);
if (params != null) {
// 内容编码设置
method.getParams().setParameter(HttpMethodParams.HTTP_CONTENT_CHARSET, codePage);
// 请求体信息设置
method.setRequestBody(assembleRequestParams(params));
// 请求头设置
method.setRequestHeader("procode", "test");
}
// 响应结果信息处理
String result = "";
try {
httpClient.executeMethod(method);
result = new String(method.getResponseBody(), codePage);
} catch (Exception e) {
throw e;
} finally {
// 释放连接
method.releaseConnection();
}
return result;
}
/**
* 组装http请求参数
*
* @param data 键值对
* @return 返回一个名称-值的键值对
*/
private synchronized static NameValuePair[] assembleRequestParams(Map<String, String> data) {
List<NameValuePair> nameValueList = new ArrayList<>();
Iterator<Map.Entry<String, String>> it = data.entrySet().iterator();
while (it.hasNext()) {
Map.Entry<String, String> entry = it.next();
nameValueList.add(new NameValuePair(entry.getKey(), entry.getValue()));
}
log.info("键值对参数:{}", ArrayUtils.toString(nameValueList.toArray(new NameValuePair[nameValueList.size()])));
return nameValueList.toArray(new NameValuePair[nameValueList.size()]);
}
/**
* get请求
*
* @param url 目标请求地址
* @return 将响应结果转换成string返回
*/
private static String get(String url) {
String result = "";
try {
// 根据地址获取请求
HttpGet request = new HttpGet(url);
request.setHeader("procode", "test");
// 获取当前客户端对
CloseableHttpClient httpclient = HttpClients.createDefault();
// 通过请求对象获取响应对象
HttpResponse response = httpclient.execute(request);
// 判断请求结果状态码
if (response.getStatusLine().getStatusCode() == HttpStatus.SC_OK) {
result = EntityUtils.toString(response.getEntity());
}
} catch (Exception e) {
e.printStackTrace();
}
return result;
}
public static void main(String[] args) throws Exception {
String url = "http://localhost:8080/sales-webapp/admin/report/smslist";
// 发起post请求
String resultPost = postMsg(url, "1");
log.info("post返回结果:{}", resultPost);
// 发起get请求
String resultGet = get(url);
log.info("get返回结果:{}", resultGet);
// 测试body有参数的post方法
Map<String, String> map = new HashMap<>(16);
map.put("age", "13");
map.put("name", "jason");
String resultPostHaveBody = postData(url, map, "UTF-8");
log.info("post带有body请求返回结果:{}", resultPostHaveBody);
}
}
参考博文:
(1) https://blog.csdn.net/q394895302/article/details/90256482 (讲的清晰明了,分开讲述两种依赖包发get和post请求)
(2) https://blog.csdn.net/u014429653/article/details/106985970 (代码清晰)