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This article mainly explains "examples of the use of HttpClient". Interested friends may wish to have a look. The method introduced in this paper is simple, fast and practical. Now let the editor take you to learn the "examples of the use of HttpClient"!

Use of HttpClient:

1) simple use of httpClient:

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. Create the Httpclient object CloseableHttpClient httpclient = HttpClients.createDefault (); / / 2.1 create the http GET request and set the parameter 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 create a http POST request and set the parameters HttpPost httpPost = new HttpPost (url); List parameters = new ArrayList (); parameters.add (new BasicNameValuePair ("name", "jack"); parameters.add (new BasicNameValuePair ("age", "1")) UrlEncodedFormEntity formEntity = new UrlEncodedFormEntity (parameters); httpPost.setEntity (formEntity); / / 3. Build request configuration information RequestConfig config = RequestConfig.custom (). SetConnectTimeout (1000) / / maximum time to create a connection. SetConnectionRequestTimeout (500) / / maximum time to get a connection from the connection pool. SetSocketTimeout (10 * 1000) / / maximum time for data transfer .setStaleConnectionCheckEnabled (true) / / Test whether the connection is available before submitting the request. Build () HttpGet.setConfig (config); httpPost.setConfig (config); CloseableHttpResponse response = null; try {/ / 4. Execute request response = httpclient.execute (httpGet); / / response = httpclient.execute (httpPost) If (response.getStatusLine (). GetStatusCode () = 200) {/ / determine whether the returned status is 200String content = EntityUtils.toString (response.getEntity (), "UTF-8"); System.out.println (content) }} finally {if (response! = null) {response.close ();} httpclient.close ();}

2) use httpClient connection pooling:

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; / / set the maximum number of connections connectionManager.setDefaultMaxPerRoute (20); / / set the number of concurrency per host address / / execute a get request 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 ();} / / httpClient cannot be closed here! If httpClient is turned off, the connection pool will also be destroyed / / httpClient.close ();}

3) Integration of HttpClient and Spring:

[1] pom.xml file:

Org.apache.httpcomponents httpclient 4.3.5

[2] spirng configuration file applicationContext-httpclient.xml:

Property profile httpclient.properties: http.maxTotal=200 http.defaultMaxPerRoute=50 http.connectTimeout=1000 http.connectionRequestTimeout=500 http.socketTimeout=10000 http.staleConnectionCheckEnabled=true

[3] encapsulated into 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);} / execute GET request public String doGet (String url) throws ClientProtocolException, IOException {HttpGet httpGet = new HttpGet (url); httpGet.setConfig (requestConfig); CloseableHttpResponse response = null Try {/ / execute request response = getHttpClient () .execute (httpGet) / / determine whether the returned status is 200if (response.getStatusLine (). GetStatusCode () = = 200) {return EntityUtils.toString (response.getEntity (), "UTF-8") }} finally {if (response! = null) {response.close ();}} return null } / / GET request with parameters public String doGet (String url, Map params) throws ClientProtocolException, IOException, URISyntaxException {URIBuilder builder = new URIBuilder (url); for (Map.Entry entry: params.entrySet ()) {builder.setParameter (entry.getKey (), entry.getValue ()) } return doGet (builder.build (). ToString ());} / execute post request public HttpResult doPost (String url, Map params) throws IOException {/ / create http POST request HttpPost httpPost = new HttpPost (url); httpPost.setConfig (requestConfig) If (null! = params) {List parameters = new ArrayList (0); for (Map.Entry entry: params.entrySet ()) {parameters.add (new BasicNameValuePair (entry.getKey (), entry.getValue () } / / construct an entity of form form 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 () } / / execute post request, send json data public HttpResult doPostJson (String url, String json) throws IOException {/ / create http POST request HttpPost httpPost = new HttpPost (url); httpPost.setConfig (requestConfig) If (null! = json) {/ / construct the entity of a string 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 ();}} / / the result returned is 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] close invalid connections on a regular basis:

Import org.apache.http.conn.HttpClientConnectionManager;public class IdleConnectionEvictor extends Thread {private final HttpClientConnectionManager connectionManager; private volatile boolean shutdown; / / when creating the IdleConnectionEvictor object, start the thread 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) / / close failed connections (check every 5 seconds) connectionManager.closeExpiredConnections () } catch (InterruptedException ex) {/ / end}} public void shutdown () {shutdown = true; synchronized (this) {notifyAll () At this point, I believe you have a deeper understanding of "examples of the use of HttpClient". You might as well do it in practice. Here is the website, more related content can enter the relevant channels to inquire, follow us, continue to learn!

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