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。
HttpClient通俗的讲就是模拟了浏览器的行为，如果我们需要在后端向某一地址提交数据获取结果，就可以使用HttpClient.
关于HttpClient（原生）具体的使用不属于我们这里的学习内容，我们这里这里为了简化HttpClient的使用，提供了工具类HttpClient（对原生HttpClient进行了封装）
依赖
<!--httpclient支持-->
<dependency>
<groupId>org.apache.httpcomponents</groupId>
<artifactId>httpclient</artifactId>
</dependency>
HttpClient工具类代码：
public class HttpClient {
private String url;
private Map<String, String> param;
private int statusCode;
private String content;
private String xmlParam;
private boolean isHttps;
public boolean isHttps() {
return isHttps;
}
public void setHttps(boolean isHttps) {
this.isHttps = isHttps;
}
public String getXmlParam() {
return xmlParam;
}
public void setXmlParam(String xmlParam) {
this.xmlParam = xmlParam;
}
public HttpClient(String url, Map<String, String> param) {
this.url = url;
this.param = param;
}
public HttpClient(String url) {
this.url = url;
}
public void setParameter(Map<String, String> map) {
param = map;
}
public void addParameter(String key, String value) {
if (param == null)
param = new HashMap<String, String>();
param.put(key, value);
}
public void post() throws ClientProtocolException, IOException {
HttpPost http = new HttpPost(url);
setEntity(http);
execute(http);
}
public void put() throws ClientProtocolException, IOException {
HttpPut http = new HttpPut(url);
setEntity(http);
execute(http);
}
public void get() throws ClientProtocolException, IOException {
if (param != null) {
StringBuilder url = new StringBuilder(this.url);
boolean isFirst = true;
for (String key : param.keySet()) {
if (isFirst) {
url.append("?");
}else {
url.append("&");
}
url.append(key).append("=").append(param.get(key));
}
this.url = url.toString();
}
HttpGet http = new HttpGet(url);
execute(http);
}
/**
* set http post,put param
*/
private void setEntity(HttpEntityEnclosingRequestBase http) {
if (param != null) {
List<NameValuePair> nvps = new LinkedList<NameValuePair>();
for (String key : param.keySet()) {
nvps.add(new BasicNameValuePair(key, param.get(key))); // 参数
}
http.setEntity(new UrlEncodedFormEntity(nvps, Consts.UTF_8)); // 设置参数
}
if (xmlParam != null) {
http.setEntity(new StringEntity(xmlParam, Consts.UTF_8));
}
}
private void execute(HttpUriRequest http) throws ClientProtocolException,
IOException {
CloseableHttpClient httpClient = null;
try {
if (isHttps) {
SSLContext sslContext = new SSLContextBuilder()
.loadTrustMaterial(null, new TrustStrategy() {
// 信任所有
@Override
public boolean isTrusted(X509Certificate[] chain,
String authType)
throws CertificateException {
return true;
}
}).build();
SSLConnectionSocketFactory sslsf = new SSLConnectionSocketFactory(
sslContext);
httpClient = HttpClients.custom().setSSLSocketFactory(sslsf)
.build();
} else {
httpClient = HttpClients.createDefault();
}
CloseableHttpResponse response = httpClient.execute(http);
try {
if (response != null) {
if (response.getStatusLine() != null) {
statusCode = response.getStatusLine().getStatusCode();
}
HttpEntity entity = response.getEntity();
// 响应内容
content = EntityUtils.toString(entity, Consts.UTF_8);
}
} finally {
response.close();
}
} catch (Exception e) {
e.printStackTrace();
} finally {
httpClient.close();
}
}
public int getStatusCode() {
return statusCode;
}
public String getContent() throws ParseException, IOException {
return content;
}
}
HttpClient工具类使用的步骤
HttpClient client=new HttpClient(请求的url地址);
client.setHttps(true);//是否是https协议
client.setXmlParam(xmlParam);//发送的xml数据
client.post();//执行post请求
String result = client.getContent(); //获取结果