Java中用于发送HTTP请求的工具类
HttpClientUtil是Java中用于发送HTTP请求的工具类，它是基于Apache HttpClient实现的。下面是一个示例代码：
import org.apache.http.HttpEntity;
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.client.utils.URIBuilder;
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;
import org.apache.http.NameValuePair;
import java.net.URI;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.List;
import java.util.Map;
public class HttpClientUtil2 {
/**
* 发送GET请求
*
* @param url 请求URL
* @return 响应内容
*/
public static String sendGet(String url) {
String result = "";
CloseableHttpClient httpClient = HttpClients.createDefault();
try {
HttpGet httpGet = new HttpGet(url);
CloseableHttpResponse response = httpClient.execute(httpGet);
HttpEntity entity = response.getEntity();
if (entity != null) {
result = EntityUtils.toString(entity, "UTF-8");
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
httpClient.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
/**
* 发送POST请求
*
* @param url 请求URL
* @param params 请求参数
* @return 响应内容
*/
public static String sendPost(String url, Map<String, String> params) {
String result = "";
CloseableHttpClient httpClient = HttpClients.createDefault();
try {
HttpPost httpPost = new HttpPost(url);
if (params != null && params.size() > 0) {
List<NameValuePair> nameValuePairList = new ArrayList<>();
for (Map.Entry<String, String> entry : params.entrySet()) {
nameValuePairList.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
}
UrlEncodedFormEntity entity = new UrlEncodedFormEntity(nameValuePairList, "UTF-8");
httpPost.setEntity(entity);
}
CloseableHttpResponse response = httpClient.execute(httpPost);
HttpEntity entity = response.getEntity();
if (entity != null) {
result = EntityUtils.toString(entity, "UTF-8");
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
httpClient.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
/**
* 发送带参数的GET请求
*
* @param url 请求URL
* @param params 请求参数
* @return 响应内容
*/
public static String sendGetWithParams(String url, Map<String, String> params) {
String result = "";
CloseableHttpClient httpClient = HttpClients.createDefault();
try {
URIBuilder uriBuilder = new URIBuilder(url);
if (params != null && params.size() > 0) {
for (Map.Entry<String, String> entry : params.entrySet()) {
uriBuilder.setParameter(entry.getKey(), entry.getValue());
}
}
URI uri = uriBuilder.build();
HttpGet httpGet = new HttpGet(uri);
CloseableHttpResponse response = httpClient.execute(httpGet);
HttpEntity entity = response.getEntity();
if (entity != null) {
result = EntityUtils.toString(entity, "UTF-8");
}
} catch (Exception e) {
e.printStackTrace();
} finally {
try {
httpClient.close();
} catch (Exception e) {
e.printStackTrace();
}
}
return result;
}
//这是一个main方法，是程序的入口:
public static void main(String[] args) {
// get 请求
// String getUrl = "https://gw.alipayobjects.com/os/antvdemo/assets/data/algorithm-category.json";
// String result = sendGet(getUrl);
// System.out.println("result = " + result);
//Post 请求 baocuo
// String postUrl = "http://localhost:8088/device/factmag/getInfo";
// Map m = new HashMap();
// m.put("Authorization","Bearer eyJhbGciOiJIUzUxMiJ9.eyJ1c2VyX2lkIjoxLCJ1c2VyX2tleSI6IjNkNmI3ZTFjLTU0ZjgtNGE2NS1iMTY1LTE2NjczYzM1MWIxZiIsInVzZXJuYW1lIjoiYWRtaW4ifQ.AyLfDdY9PjpWInEnaiDUBdJVpStEsP1oheWrxCdRcflzJSWPL2VMFFL2SngTO5S0jrI3uwQBWAsccCOG4hRygg");
// m.put("facregCode","999999");
// String s = sendPost(postUrl, m);
//System.out.println("s = " + s);
/*String sendGetWithParamsUrl = "http://localhost:9888/boxes2/getprojectinfo";
Map m = new HashMap();
m.put("mac","98CC4D111DDE");
String s = sendGetWithParams(sendGetWithParamsUrl, m);
System.out.println("s = " + s);*/
}
}
上述示例代码中，sendGet方法用于发送GET请求，sendPost方法用于发送POST请求，sendGetWithParams方法用于发送带参数的GET请求。这些方法都使用了相同的HTTP客户端实例，在请求结束后关闭该实例以释放资源。
在使用HttpClientUtil时，需要将Apache HttpClient的相关依赖项添加到项目的构建路径下，例如：
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
<version>4.5.13</version>
</dependency>