本篇内容主要讲解“HttpClient的使用实例”，感兴趣的朋友不妨来看看。本文介绍的方法操作简单快捷，实用性强。下面就让小编来带大家学习“HttpClient的使用实例”吧!
HttpClient的使用：
1）httpClient的简单使用：
import java.net.URI;
import java.util.ArrayList;
import java.util.List;
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.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;
public class HttpClientDemo {
public static void main(String[] args) throws Exception {
// 1.创建Httpclient对象
CloseableHttpClient httpclient = HttpClients.createDefault();
// 2.1创建http GET请求，并设置参数
String url = "http://www.jxn.com/";
URI uri = new URIBuilder(url).setParameter("name", "jack").setParameter("age", "1").build();
HttpGet httpGet = new HttpGet(uri);
// 2.2创建http POST请求，并设置参数
HttpPost httpPost = new HttpPost(url);
List<NameValuePair> parameters = new ArrayList<NameValuePair>();
parameters.add(new BasicNameValuePair("name", "jack"));
parameters.add(new BasicNameValuePair("age", "1"));
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters);
httpPost.setEntity(formEntity);
// 3.构建请求配置信息
RequestConfig config = RequestConfig.custom().setConnectTimeout(1000) // 创建连接的最长时间
.setConnectionRequestTimeout(500) // 从连接池中获取到连接的最长时间
.setSocketTimeout(10 * 1000) // 数据传输的最长时间
.setStaleConnectionCheckEnabled(true) // 提交请求前测试连接是否可用
.build();
httpGet.setConfig(config);
httpPost.setConfig(config);
CloseableHttpResponse response = null;
try {
// 4.执行请求
response = httpclient.execute(httpGet);
// response = httpclient.execute(httpPost);
if (response.getStatusLine().getStatusCode() == 200) { // 判断返回状态是否为200
String content = EntityUtils.toString(response.getEntity(), "UTF-8");
System.out.println(content);
}
} finally {
if (response != null) {
response.close();
}
httpclient.close();
}
}
}2）使用httpClient连接池：
import org.apache.http.client.methods.CloseableHttpResponse;
import org.apache.http.client.methods.HttpGet;
import org.apache.http.conn.HttpClientConnectionManager;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.impl.client.HttpClients;
import org.apache.http.impl.conn.PoolingHttpClientConnectionManager;
import org.apache.http.util.EntityUtils;
public class HttpClientConnectionManagerDemo {
public static void main(String[] args) throws Exception {
PoolingHttpClientConnectionManager connectionManager = new PoolingHttpClientConnectionManager();
connectionManager.setMaxTotal(200); // 设置最大连接数
connectionManager.setDefaultMaxPerRoute(20); // 设置每个主机地址的并发数
// 执行一次get请求
doGet(connectionManager);
}
public static void doGet(HttpClientConnectionManager connectionManager) throws Exception {
CloseableHttpClient httpClient = HttpClients.custom().setConnectionManager(connectionManager).build();
String url = "http://www.jxn.com/";
HttpGet httpGet = new HttpGet(url);
CloseableHttpResponse response = null;
try {
response = httpClient.execute(httpGet);
if (response.getStatusLine().getStatusCode() == 200) {
String content = EntityUtils.toString(response.getEntity(), "UTF-8");
System.out.println(content);
}
} finally {
if (response != null) {
response.close();
}
// 此处不能关闭httpClient！如果把httpClient关闭掉，则连接池也会被销毁
// httpClient.close();
}
}
}3）HttpClient与Spring整合：
【1】pom.xml文件：
<dependency> <groupId>org.apache.httpcomponents</groupId> <artifactId>httpclient</artifactId> <version>4.3.5</version> </dependency>
【2】spirng配置文件applicationContext-httpclient.xml：
<!-- 定义httpClient连接管理器 -->
<bean id="httpClientConnectionManager"
class="org.apache.http.impl.conn.PoolingHttpClientConnectionManager">
<property name="maxTotal" value="${http.maxTotal}" />
<property name="defaultMaxPerRoute" value="${http.defaultMaxPerRoute}" />
</bean>
<!-- httpclient的构建器 -->
<bean id="httpClientBuilder" class="org.apache.http.impl.client.HttpClientBuilder">
<property name="connectionManager" ref="httpClientConnectionManager" />
</bean>
<!-- 定义Httpclient对象。注意：该对象是多例的！ -->
<bean class="org.apache.http.impl.client.CloseableHttpClient"
factory-bean="httpClientBuilder" factory-method="build" scope="prototype">
</bean>
<!-- 请求参数的构建器 -->
<bean id="requestConfigBuilder" class="org.apache.http.client.config.RequestConfig.Builder">
<!-- 创建连接的最长时间 -->
<property name="connectTimeout" value="${http.connectTimeout}" />
<!-- 从连接池中获取到连接的最长时间 -->
<property name="connectionRequestTimeout" value="${http.connectionRequestTimeout}" />
<!-- 数据传输的最长时间 -->
<property name="socketTimeout" value="${http.socketTimeout}" />
<!-- 提交请求前测试连接是否可用 -->
<property name="staleConnectionCheckEnabled" value="${http.staleConnectionCheckEnabled}" />
</bean>
<!-- 定义请求参数对象 -->
<bean class="org.apache.http.client.config.RequestConfig" factory-bean="requestConfigBuilder" factory-method="build" />
<!-- 定期关闭无效的连接 -->
<bean class="com.jxn.common.httpclient.IdleConnectionEvictor">
<constructor-arg index="0" ref="httpClientConnectionManager" />
</bean>
属性配置文件httpclient.properties：
http.maxTotal=200
http.defaultMaxPerRoute=50
http.connectTimeout=1000
http.connectionRequestTimeout=500
http.socketTimeout=10000
http.staleConnectionCheckEnabled=true【3】封装成Service：
import java.io.IOException;
import java.net.URISyntaxException;
import java.util.ArrayList;
import java.util.List;
import java.util.Map;
import org.apache.http.NameValuePair;
import org.apache.http.client.ClientProtocolException;
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.client.utils.URIBuilder;
import org.apache.http.entity.ContentType;
import org.apache.http.entity.StringEntity;
import org.apache.http.impl.client.CloseableHttpClient;
import org.apache.http.message.BasicNameValuePair;
import org.apache.http.util.EntityUtils;
import org.springframework.beans.BeansException;
import org.springframework.beans.factory.BeanFactory;
import org.springframework.beans.factory.BeanFactoryAware;
import org.springframework.beans.factory.annotation.Autowired;
import org.springframework.stereotype.Service;
import com.jxn.common.httpclient.HttpResult;
[@Service](https://my.oschina.net/service)
public class ApiService implements BeanFactoryAware {
private BeanFactory beanFactory;
@Autowired(required = false)
private RequestConfig requestConfig;
[@Override](https://my.oschina.net/u/1162528)
public void setBeanFactory(BeanFactory beanFactory) throws BeansException {
this.beanFactory = beanFactory;
}
private CloseableHttpClient getHttpClient() {
return this.beanFactory.getBean(CloseableHttpClient.class);
}
// 执行GET请求
public String doGet(String url) throws ClientProtocolException, IOException {
HttpGet httpGet = new HttpGet(url);
httpGet.setConfig(requestConfig);
CloseableHttpResponse response = null;
try {
// 执行请求
response = getHttpClient().execute(httpGet);
// 判断返回状态是否为200
if (response.getStatusLine().getStatusCode() == 200) {
return EntityUtils.toString(response.getEntity(), "UTF-8");
}
} finally {
if (response != null) {
response.close();
}
}
return null;
}
// 带有参数的GET请求
public String doGet(String url, Map<String, String> params) throws ClientProtocolException, IOException,
URISyntaxException {
URIBuilder builder = new URIBuilder(url);
for (Map.Entry<String, String> entry : params.entrySet()) {
builder.setParameter(entry.getKey(), entry.getValue());
}
return doGet(builder.build().toString());
}
// 执行post请求
public HttpResult doPost(String url, Map<String, String> params) throws IOException {
// 创建http POST请求
HttpPost httpPost = new HttpPost(url);
httpPost.setConfig(requestConfig);
if (null != params) {
List<NameValuePair> parameters = new ArrayList<NameValuePair>(0);
for (Map.Entry<String, String> entry : params.entrySet()) {
parameters.add(new BasicNameValuePair(entry.getKey(), entry.getValue()));
}
// 构造一个form表单式的实体
UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity(parameters, "UTF-8");
httpPost.setEntity(formEntity);
}
CloseableHttpResponse response = null;
try {
response = getHttpClient().execute(httpPost);
return new HttpResult(response.getStatusLine().getStatusCode(), EntityUtils.toString(
response.getEntity(), "UTF-8"));
} finally {
if (response != null) {
response.close();
}
}
}
// 执行post请求，发送json数据
public HttpResult doPostJson(String url, String json) throws IOException {
// 创建http POST请求
HttpPost httpPost = new HttpPost(url);
httpPost.setConfig(requestConfig);
if (null != json) {
// 构造一个字符串的实体
StringEntity stringEntity = new StringEntity(json, ContentType.APPLICATION_JSON);
httpPost.setEntity(stringEntity);
}
CloseableHttpResponse response = null;
try {
response = getHttpClient().execute(httpPost);
return new HttpResult(response.getStatusLine().getStatusCode(), EntityUtils.toString(
response.getEntity(), "UTF-8"));
} finally {
if (response != null) {
response.close();
}
}
}
}
// 返回的结果
public class HttpResult {
private Integer code;
private String data;
public HttpResult() {
}
public HttpResult(Integer code, String data) {
this.code = code;
this.data = data;
}
public Integer getCode() {
return code;
}
public void setCode(Integer code) {
this.code = code;
}
public String getData() {
return data;
}
public void setData(String data) {
this.data = data;
}
}【4】实现定期关闭无效的连接：
import org.apache.http.conn.HttpClientConnectionManager;
public class IdleConnectionEvictor extends Thread {
private final HttpClientConnectionManager connectionManager;
private volatile boolean shutdown;
// 创建IdleConnectionEvictor对象的时候，启动线程
public IdleConnectionEvictor(HttpClientConnectionManager connectionManager) {
this.connectionManager = connectionManager;
this.start();
}
[@Override](https://my.oschina.net/u/1162528)
public void run() {
try {
while (!shutdown) {
synchronized (this) {
wait(5000);
// 关闭失效的连接(每隔5秒检查一次)
connectionManager.closeExpiredConnections();
}
}
} catch (InterruptedException ex) {
// 结束
}
}
public void shutdown() {
shutdown = true;
synchronized (this) {
notifyAll();
}
}
}到此，相信大家对“HttpClient的使用实例”有了更深的了解，不妨来实际操作一番吧！这里是亿速云网站，更多相关内容可以进入相关频道进行查询，关注我们，继续学习！
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